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Chen P, Ding N, Pan D, Chen X, Li S, Luo Y, Chen Z, Xu Y, Zhu X, Wang K, Zou W. PET imaging for the early evaluation of ocular inflammation in diabetic rats by using [ 18F]-DPA-714. Exp Eye Res 2024; 245:109986. [PMID: 38945519 DOI: 10.1016/j.exer.2024.109986] [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: 09/11/2023] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/02/2024]
Abstract
Ocular complications of diabetes mellitus (DM) are the leading cause of vision loss. Ocular inflammation often occurs in the early stage of DM; however, there are no proven quantitative methods to evaluate the inflammatory status of eyes in DM. The 18 kDa translocator protein (TSPO) is an evolutionarily conserved cholesterol binding protein localized in the outer mitochondrial membrane. It is a biomarker of activated microglia/macrophages; however, its role in ocular inflammation is unclear. In this study, fluorine-18-DPA-714 ([18F]-DPA-714) was evaluated as a specific TSPO probe by cell uptake, cell binding assays and micro positron emission tomography (microPET) imaging in both in vitro and in vivo models. Primary microglia/macrophages (PMs) extracted from the cornea, retina, choroid or sclera of neonatal rats with or without high glucose (50 mM) treatment were used as the in vitro model. Sprague-Dawley (SD) rats that received an intraperitoneal administration of streptozotocin (STZ, 60 mg/kg once) were used as the in vivo model. Increased cell uptake and high binding affinity of [18F]-DPA-714 were observed in primary PMs under hyperglycemic stress. These findings were consistent with cellular morphological changes, cell activation, and TSPO up-regulation. [18F]-DPA-714 PET imaging and biodistribution in the eyes of DM rats revealed that inflammation initiates in microglia/macrophages in the early stages (3 weeks and 6 weeks), corresponding with up-regulated TSPO levels. Thus, [18F]-DPA-714 microPET imaging may be an effective approach for the early evaluation of ocular inflammation in DM.
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Affiliation(s)
- Peng Chen
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Jintan Affiliated Hospital of Jiangsu University, Changzhou, Jiangsu, China
| | - Nannan Ding
- Department of Ophthalmology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center (JUMC), Wuxi, Jiangsu, China; Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China
| | - Donghui Pan
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xuelian Chen
- Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, PuNan Branch of Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - ShiYi Li
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Jingjiang People's Hospital Affiliated to Yangzhou University, Taizhou, Jiangsu, China
| | - Yidan Luo
- Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China
| | - Ziqing Chen
- Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China
| | - Yuping Xu
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xue Zhu
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ke Wang
- National Health Commission (NHC) Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Wenjun Zou
- Department of Ophthalmology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center (JUMC), Wuxi, Jiangsu, China; Department of Ophthalmology, The Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, China; Department of Ophthalmology, Affiliated Wuxi Clinical College of Nantong Medical University, Wuxi, Jiangsu, China.
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Hector M, Langmann T, Wolf A. Translocator protein (18 kDa) (Tspo) in the retina and implications for ocular diseases. Prog Retin Eye Res 2024; 100:101249. [PMID: 38430990 DOI: 10.1016/j.preteyeres.2024.101249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
Translocator protein (18 kDa) (Tspo), formerly known as peripheral benzodiazepine receptor is a highly conserved transmembrane protein primarily located in the outer mitochondrial membrane. In the central nervous system (CNS), especially in glia cells, Tspo is upregulated upon inflammation. Consequently, Tspo was used as a tool for diagnostic in vivo imaging of neuroinflammation in the brain and as a potential therapeutic target. Several synthetic Tspo ligands have been explored as immunomodulatory and neuroprotective therapy approaches. Although the function of Tspo and how its ligands exert these beneficial effects is not fully clear, it became a research topic of interest, especially in ocular diseases in the past few years. This review summarizes state-of-the-art knowledge of Tspo expression and its proposed functions in different cells of the retina including microglia, retinal pigment epithelium and Müller cells. Tspo is involved in cytokine signaling, oxidative stress and reactive oxygen species production, calcium signaling, neurosteroid synthesis, energy metabolism, and cholesterol efflux. We also highlight recent developments in preclinical models targeting Tspo and summarize the relevance of Tspo biology for ocular and retinal diseases. We conclude that glial upregulation of Tspo in different ocular pathologies and the use of Tspo ligands as promising therapeutic approaches in preclinical studies underline the importance of Tspo as a potential disease-modifying protein.
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Affiliation(s)
- Mandy Hector
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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Yu M, Zhao S. Functional role of translocator protein and its ligands in ocular diseases (Review). Mol Med Rep 2024; 29:33. [PMID: 38186312 PMCID: PMC10804439 DOI: 10.3892/mmr.2024.13157] [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: 08/17/2023] [Accepted: 12/08/2023] [Indexed: 01/09/2024] Open
Abstract
The 18 kDa translocator protein (TSPO) is an essential outer mitochondrial membrane protein that is responsible for mitochondrial transport, maintenance of mitochondrial homeostasis and normal physiological cell function. The role of TSPO in the pathogenesis of ocular diseases is a growing area of interest. More notably, TSPO exerts positive effects in regulating various pathophysiological processes, such as the inflammatory response, oxidative stress, steroid synthesis and modulation of microglial function, in combination with a variety of specific ligands such as 1‑(2‑chlorophenyl‑N‑methylpropyl)‑3‑isoquinolinecarboxamide, 4'‑chlorodiazepam and XBD173. In the present review, the expression of TSPO in ocular tissues and the functional role of TSPO and its ligands in diverse ocular diseases was discussed.
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Affiliation(s)
- Mingyi Yu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 30384, P.R. China
| | - Shaozhen Zhao
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 30384, P.R. China
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Baburina YL, Zvyagina AI, Odinokova IV, Krestinina OV. [Effect of erastin and G3139 on rat liver mitochondria in chronic alcoholic intoxication]. BIOMEDITSINSKAIA KHIMIIA 2023; 69:62-71. [PMID: 36857428 DOI: 10.18097/pbmc20236901062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The effect of modulators of VDAC channels - G3139 and erastin on the mitochondrial permeability transition pore (mPTP) functioning and changes in the content of proteins involved in regulation of mPTP (VDAC, CNPase, and TSPO) has been investigated in liver mitochondria of rats with chronic alcohol intoxication. It was shown that the mitochondria of rats treated with ethanol were more sensitive to mPTP induction. Moreover, ethanol induced changes in the expression of mPTP regulator proteins. G3139 and erastin were also able to influence the studied mitochondrial parameters, and they increased their effect in the liver mitochondria of rats treated with ethanol, as compared to the mitochondria of control rats. We hypothesize that the results of this study may help to elucidate the mechanisms of chronic action of ethanol on mitochondria and contribute to the development of new therapeutic strategies for treating the consequences of ethanol-related diseases.
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Affiliation(s)
- Yu L Baburina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - A I Zvyagina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - I V Odinokova
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - O V Krestinina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
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