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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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Guo J, Chen S, Zhang Y, Liu J, Jiang L, Hu L, Yao K, Yu Y, Chen X. Cholesterol metabolism: physiological regulation and diseases. MedComm (Beijing) 2024; 5:e476. [PMID: 38405060 PMCID: PMC10893558 DOI: 10.1002/mco2.476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/27/2024] Open
Abstract
Cholesterol homeostasis is crucial for cellular and systemic function. The disorder of cholesterol metabolism not only accelerates the onset of cardiovascular disease (CVD) but is also the fundamental cause of other ailments. The regulation of cholesterol metabolism in the human is an extremely complex process. Due to the dynamic balance between cholesterol synthesis, intake, efflux and storage, cholesterol metabolism generally remains secure. Disruption of any of these links is likely to have adverse effects on the body. At present, increasing evidence suggests that abnormal cholesterol metabolism is closely related to various systemic diseases. However, the exact mechanism by which cholesterol metabolism contributes to disease pathogenesis remains unclear, and there are still unknown factors. In this review, we outline the metabolic process of cholesterol in the human body, especially reverse cholesterol transport (RCT). Then, we discuss separately the impact of abnormal cholesterol metabolism on common diseases and potential therapeutic targets for each disease, including CVD, tumors, neurological diseases, and immune system diseases. At the end of this review, we focus on the effect of cholesterol metabolism on eye diseases. In short, we hope to provide more new ideas for the pathogenesis and treatment of diseases from the perspective of cholesterol.
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Affiliation(s)
- Jiarui Guo
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Silong Chen
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Ying Zhang
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
- Institute of Translational MedicineZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Jinxia Liu
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Luyang Jiang
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Lidan Hu
- National Clinical Research Center for Child HealthThe Children's HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Ke Yao
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Yibo Yu
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
| | - Xiangjun Chen
- Eye Center of the Second Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
- Institute of Translational MedicineZhejiang University School of MedicineHangzhouZhejiang ProvinceChina
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Zhang J, Wei J, Liu T, Tang J, Zhang X, Feng F, Cai H, Zhao M. Food additive glycerol monocaprylate modulated systemic inflammation and gut microbiota without stimulating metabolic dysfunction in high-fat diet fed mice. Food Res Int 2023; 167:112734. [PMID: 37087285 DOI: 10.1016/j.foodres.2023.112734] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023]
Abstract
Recent findings imply that great consideration should be given to the potential health risks of food additives on gut microbiota. Glycerol monocaprylate (GMC) is a widely consumed food preservative and emulsifier. Our results indicated that GMC significantly ameliorated visceral fat accumulation and systemic inflammation in high-fat diet (HFD)-fed mice. Furthermore, GMC induced improvements on the composition and function of gut microbiota, resulting in increased beneficial gut bacteria (Bifidobacterium and Lactobacillus) and promoted production of short chain fatty acids. Notably, GMC-induced metabolic amelioration is closely related to the regulation in gut microbiota. Overall, our findings supported that unlike the emulsifiers previously reported to damage intestinal health, GMC performed the potential on attenuating HFD-induced metabolic disorders and gut microbiota dysbiosis, which also refined on the safety evaluation of GMC on gut microbiota. Our findings suggest that when evaluating the safety of food additives with regards to gut microbiota, it is important to take into account the specific characteristics of the additive in question, rather than simply relying on its classification.
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Affiliation(s)
- Junhui Zhang
- College of Biosystems Engineering and Food Science, Ningbo Research Institute, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Zhejiang 310058, China; ZhongYuan Institute, Zhejiang University, Zhengzhou 450001, China
| | - Ji'an Wei
- Mizuda Group Co., Ltd/Hangzhou Xinchao Enterprise Management Consulting Co., Ltd, Huzhou 313000, China
| | - Tao Liu
- College of Biosystems Engineering and Food Science, Ningbo Research Institute, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Zhejiang 310058, China; ZhongYuan Institute, Zhejiang University, Zhengzhou 450001, China
| | - Jun Tang
- School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Xi Zhang
- School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, China
| | - Fengqin Feng
- College of Biosystems Engineering and Food Science, Ningbo Research Institute, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Zhejiang 310058, China; ZhongYuan Institute, Zhejiang University, Zhengzhou 450001, China
| | - Haiying Cai
- School of Biological & Chemical Engineering, Zhejiang Key Lab for Chem & Bio Processing Technology of Farm Product, Zhejiang University of Science and Technology, Hangzhou 310023, China; Mizuda Group Co., Ltd/Hangzhou Xinchao Enterprise Management Consulting Co., Ltd, Huzhou 313000, China.
| | - Minjie Zhao
- College of Biosystems Engineering and Food Science, Ningbo Research Institute, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Zhejiang 310058, China; ZhongYuan Institute, Zhejiang University, Zhengzhou 450001, China.
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Gromova OA, Torshin IY. [Systematic analysis of the results of fundamental and clinical studies of ethifoxin]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:65-73. [PMID: 37315244 DOI: 10.17116/jnevro202312305165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The main pharmacological use of etifoxine is the treatment of psychosomatic manifestations of anxiety. The purpose of this work is a systematic analysis of fundamental and clinical studies of etifoxine. In addition to the anxiolytic effect, which partially persists even after discontinuation of therapy, etifoxine is characterized by analgesic, neurotrophic and neuroprotective properties. Such a pharmacological profile of etifoxine is due not only to the activation of GABA receptors, but also to the effect on the levels of neurosteroids in the blood and in the brain. Modulation by etifoxine of neurosteroids' metabolism contributes to the manifestation of anxiolytic, anti-inflammatory, neuroprotective and other properties of etifoxine.
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Affiliation(s)
- O A Gromova
- Federal Research Center «Computer Science and Control», Moscow, Russian
| | - I Yu Torshin
- Federal Research Center «Computer Science and Control», Moscow, Russian
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High-Fat Diet Alters the Retinal Pigment Epithelium and Choroidal Transcriptome in the Absence of Gut Microbiota. Cells 2022; 11:cells11132076. [PMID: 35805160 PMCID: PMC9266037 DOI: 10.3390/cells11132076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Relationships between retinal disease, diet, and the gut microbiome have started to emerge. In particular, high-fat diets (HFDs) are associated with the prevalence and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). These effects are thought to be partly mediated by the gut microbiome, which modulates interactions between diet and host homeostasis. Nevertheless, the effects of HFDs on the retina and adjacent retinal pigment epithelium (RPE) and choroid at the transcriptional level, independent of gut microbiota, are not well-understood. In this study, we performed the high-throughput RNA-sequencing of germ-free (GF) mice to explore the transcriptional changes induced by HFD in the RPE/choroid. After filtering and cleaning the data, 649 differentially expressed genes (DEGs) were identified, with 616 genes transcriptionally upregulated and 33 genes downregulated by HFD compared to a normal diet (ND). Enrichment analysis for gene ontology (GO) using the DEGs was performed to analyze over-represented biological processes in the RPE/choroid of GF-HFD mice relative to GF-ND mice. GO analysis revealed the upregulation of processes related to angiogenesis, immune response, and the inflammatory response. Additionally, molecular functions that were altered involved extracellular matrix (ECM) binding, ECM structural constituents, and heparin binding. This study demonstrates novel data showing that HFDs can alter RPE/choroid tissue transcription in the absence of the gut microbiome.
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Nadeem U, Boachie-Mensah M, Zhang J, Skondra D. Gut microbiome and retinal diseases: an updated review. Curr Opin Ophthalmol 2022; 33:195-201. [PMID: 35132003 DOI: 10.1097/icu.0000000000000836] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The gut microbiome, trillions of microorganisms residing in our digestive tract, is now believed to play a significant role in retinal diseases. Breakthroughs in computational biology and specialized animal models have allowed researchers not only to characterize microbes associated with retinal diseases, but also to provide early insights into the function of the microbiome in relation to biological processes in the retinal microenvironment. This review aims to provide an update on recent advances in the current knowledge on the relationship between the gut microbiome and retinal disorders. RECENT FINDINGS Recent work demonstrates distinct gut microbial compositions associated with retinal diseases such as agerelated macular degeneration and retinopathy of prematurity. Currently, it is believed that gut dysbiosis leads to increased gut permeability, elevated circulation of bacterial products, microbial metabolites and inflammatory mediators that result in immune dysregulation at distant anatomic sites including the retina. SUMMARY Emerging evidence for the gut-retina axis can elucidate previously unknown pathways involved in retinal diseases and also presents an exciting potential therapeutic avenue. Further preclinical and clinical studies are necessary to establish causation and delineate the precise relationship of the gut microbiome with retinal disorders.
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Affiliation(s)
| | | | | | - Dimitra Skondra
- Department of Ophthalmology and Visual Science
- Microbiome Medicine Program, Retina Microbiome Team, University of Chicago, Chicago, Illinois, USA
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Abstract
Oscillospira is a class of organism that often appears in high-throughput sequencing data but has not been purely cultured and is widely present in the animal and human intestines. There is a strong association between variation in Oscillospira abundance and obesity, leanness, and human health. In addition, a growing body of studies has shown that Oscillospira is also implicated in other diseases, such as gallstones and chronic constipation, and has shown some correlation with the positive or negative changes in its course. Sequencing data combined with metabolic profiling indicate that Oscillospira is likely to be a genus capable of producing short-chain fatty acids (SCFAs) such as butyrate, which is an important reference indicator for screening "next-generation probiotics ". Considering the positive effects of Oscillospira in some specific diseases, such as obesity-related metabolic diseases, it has already been characterized as one of the next-generation probiotic candidates and therefore has great potential for development and application in the future food, health care, and biopharmaceutical products.
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Affiliation(s)
- Jingpeng Yang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China,CONTACT Jingpeng Yang
| | - Yanan Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zhiqiang Wen
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Wenzheng Liu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Lingtong Meng
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China,He Huang School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, China
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Farhan F, Almarhoun M, Wong A, Findlay AS, Bartholomew C, Williams MTS, Hurd TW, Shu X. Deletion of TSPO Causes Dysregulation of Cholesterol Metabolism in Mouse Retina. Cells 2021; 10:3066. [PMID: 34831289 PMCID: PMC8621976 DOI: 10.3390/cells10113066] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/22/2022] Open
Abstract
Cholesterol dysregulation has been implicated in age-related macular degeneration (AMD), the most common cause of visual impairment in the elderly. The 18 KDa translocator protein (TSPO) is a mitochondrial outer membrane protein responsible for transporting cholesterol from the mitochondrial outer membrane to the inner membrane. TSPO is highly expressed in retinal pigment epithelial (RPE) cells, and TSPO ligands have shown therapeutic potential for the treatment of AMD. Here, we characterized retinal pathology of Tspo knockout (KO) mice using histological, immunohistochemical, biochemical and molecular biological approaches. We found that Tspo KO mice had normal retinal morphology (by light microscopy) but showed elevated levels of cholesterol, triglycerides and phospholipids with perturbed cholesterol efflux in the RPE cells of Tspo KO mice. Expression of cholesterol-associated genes (Nr1h3, Abca1, Abcg1, Cyp27a1 and Cyp46a1) was significantly downregulated, and production of pro-inflammatory cytokines was markedly increased in Tspo KO retinas. Furthermore, microglial activation was also observed in Tspo KO mouse retinas. These findings provide new insights into the function of TSPO in the retina and may aid in the design of new therapeutic strategies for the treatment of AMD.
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Affiliation(s)
- Fahad Farhan
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
| | - Mohammad Almarhoun
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
| | - Aileen Wong
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
| | - Amy S. Findlay
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK; (A.S.F.); (T.W.H.)
| | - Chris Bartholomew
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
| | - Mark T. S. Williams
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
| | - Toby W. Hurd
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK; (A.S.F.); (T.W.H.)
| | - Xinhua Shu
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK; (F.F.); (M.A.); (A.W.); (C.B.); (M.T.S.W.)
- School of Basic Medical Sciences, Shaoyang University, Shaoyang 422000, China
- Department of Vision Science, Glasgow Caledonian University, Glasgow G4 0BA, UK
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