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Shen Z, Sheng H, Zhao J, Xu J, Cai Z, Zhang H, Guo Z, Liu J, Liang H, Tan L, Gan S, Huang J, Zhu S. AQP8 Modulates Mitochondrial H 2O 2 Transport to Influence Glioma Proliferation. Cancer Invest 2024; 42:345-356. [PMID: 38742677 DOI: 10.1080/07357907.2024.2352467] [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: 01/06/2024] [Accepted: 05/03/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND Aquaporin-8 (AQP8) is involved in impacting glioma proliferation and can effect tumour growth by regulating Intracellular reactive oxygen species (ROS) signalling levels. In addition to transporting H2O2, AQP8 has been shown to affect ROS signaling, but evidence is lacking in gliomas. In this study, we aimed to investigate how AQP8 affects ROS signaling in gliomas. MATERIALS AND METHODS We constructed A172 and U251 cell lines with AQP8 knockdown and AQP8 rescue by CRISPR/Cas9 technology and overexpression of lentiviral vectors. We used CCK-8 and flow cytometry to test cell proliferation and cycle, immunofluorescence and Mito-Tracker CMXRos to observe the distribution of AQP8 expression in glioma cells, Amplex and DHE to study mitochondria release of H2O2, mitochondrial membrane potential (MMP) and NAD+/NADH ratio to assess mitochondrial function and protein blotting to detect p53 and p21 expression. RESULT We found that AQP8 co-localised with mitochondria and that knockdown of AQP8 inhibited the release of H2O2 from mitochondria and led to increased levels of ROS in mitochondria, thereby impairing mitochondrial function. We also discovered that AQP8 knockdown resulted in suppression of cell proliferation and was blocked at the G0/G1 phase with increased expression of mitochondrial ROS signalling-related p53/p21. CONCLUSIONS This finding provides further evidence for mechanistic studies of AQP8 as a prospective target for the treatment of gliomas.
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Affiliation(s)
- ZiHao Shen
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - HuaJun Sheng
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - Jing Zhao
- Xi'an Hospital of TCM, Xi'an, PR China
| | - Jin Xu
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - ZiLing Cai
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - Hao Zhang
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - Zhen Guo
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - JunNan Liu
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - Hang Liang
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - LiHao Tan
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - ShengWei Gan
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - Juan Huang
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
| | - ShuJuan Zhu
- Department of Human Anatomy, College of Basic Medicine, Chongqing Medical University, Chongqing, PR China
- Neuroscience Research Center, Chongqing Medical University, Chongqing, PR China
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Liu SH, Lin WC, Liao EC, Lin YF, Wang CS, Lee SY, Pei D, Hsu CH. Aquaporin-8 promotes human dermal fibroblasts to counteract hydrogen peroxide-induced oxidative damage: A novel target for management of skin aging. Open Life Sci 2024; 19:20220828. [PMID: 38465340 PMCID: PMC10921499 DOI: 10.1515/biol-2022-0828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 03/12/2024] Open
Abstract
The skin is subjected to various external factors that contribute to aging including oxidative stress from hydrogen peroxide (H2O2). This study investigated the distribution of aquaporin-8 (AQP8), a protein that transports H2O2 across biological membranes, in skin cells, and its effects in mitigating H2O2-induced oxidative damage. Human dermal fibroblasts were treated with increasing concentrations of H2O2 to evaluate oxidative damage. Cell viability, reactive oxygen species (ROS) generation, and the expression of specific genes associated with skin aging (IL-10, FPR2, COL1A1, KRT19, and Aggrecan) were evaluated and AQP8 expression was assessed via quantitative polymerase chain reaction and western blotting. Small-interfering RNA was used to silence the AQP8 gene and evaluate its significance. The results show that H2O2 treatment reduces cell viability and increases ROS generation, leading to oxidative damage that affects the expression of target molecules. Interestingly, H2O2-treated cells exhibit high levels of AQP8 expression and gene silencing of AQP8 reverses high levels of ROS and low levels of COL1A1, KRT19, and Aggrecan expression in stressed cells, indicating that AQP8 plays a vital role in preventing oxidative damage and consequent aging. In conclusion, AQP8 is upregulated in human dermal fibroblasts during H2O2-induced oxidative stress and may help prevent oxidative damage and aging. These findings suggest that AQP8 could be a potential therapeutic target for skin aging. Further research is necessary to explore the feasibility of using AQP8 as a preventive or therapeutic strategy for maintaining skin health.
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Affiliation(s)
- Shu-Hsiang Liu
- School of Nursing, College of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Wei-Chun Lin
- School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - En-Chih Liao
- Department of Medicine, MacKay Medical College, New Taipei, Taiwan
- Institute of Biomedical Sciences, MacKay Medical College, New Taipei, Taiwan
| | - Yung-Feng Lin
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Ching-Shuen Wang
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sheng-Yang Lee
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Dentistry, Wan-Fang Medical Center, Taipei Medical University, Taipei, Taiwan
| | - Dee Pei
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Fu Jen Catholic University Hospital, New Taipei, Taiwan
- Department of Family Medicine, Taipei City Hospital, Heping Fuyou Branch, No. 12, Fuzhou St., Zhongzheng Dist., Taipei City 100, Taiwan (R.O.C.)
| | - Chun-Hsien Hsu
- Department of Family Medicine, Taipei City Hospital, Heping Fuyou Branch, No. 12, Fuzhou St., Zhongzheng Dist., Taipei City 100, Taiwan (R.O.C.)
- Wanhua District Health Center, Department of Health, Taipei City Government, Taipei, Taiwan
- School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei, Taiwan
- Department of Exercise and Health Sciences, University of Taipei, Taipei, Taiwan
- Department of Family Medicine, Cardinal Tien Hospital, New Taipei, Taiwan
- Department of Family Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
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3
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Deans JR, Deol P, Titova N, Radi SH, Vuong LM, Evans JR, Pan S, Fahrmann J, Yang J, Hammock BD, Fiehn O, Fekry B, Eckel-Mahan K, Sladek FM. HNF4α isoforms regulate the circadian balance between carbohydrate and lipid metabolism in the liver. Front Endocrinol (Lausanne) 2023; 14:1266527. [PMID: 38111711 PMCID: PMC10726135 DOI: 10.3389/fendo.2023.1266527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/06/2023] [Indexed: 12/20/2023] Open
Abstract
Hepatocyte Nuclear Factor 4α (HNF4α), a master regulator of hepatocyte differentiation, is regulated by two promoters (P1 and P2) which drive the expression of different isoforms. P1-HNF4α is the major isoform in the adult liver while P2-HNF4α is thought to be expressed only in fetal liver and liver cancer. Here, we show that P2-HNF4α is indeed expressed in the normal adult liver at Zeitgeber time (ZT)9 and ZT21. Using exon swap mice that express only P2-HNF4α we show that this isoform orchestrates a distinct transcriptome and metabolome via unique chromatin and protein-protein interactions, including with different clock proteins at different times of the day leading to subtle differences in circadian gene regulation. Furthermore, deletion of the Clock gene alters the circadian oscillation of P2- (but not P1-)HNF4α RNA, revealing a complex feedback loop between the HNF4α isoforms and the hepatic clock. Finally, we demonstrate that while P1-HNF4α drives gluconeogenesis, P2-HNF4α drives ketogenesis and is required for elevated levels of ketone bodies in female mice. Taken together, we propose that the highly conserved two-promoter structure of the Hnf4a gene is an evolutionarily conserved mechanism to maintain the balance between gluconeogenesis and ketogenesis in the liver in a circadian fashion.
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Affiliation(s)
- Jonathan R. Deans
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
- Genetics, Genomics and Bioinformatics Graduate Program, University of California, Riverside, Riverside, CA, United States
| | - Poonamjot Deol
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Nina Titova
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Sarah H. Radi
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
- Biochemistry and Molecular Biology Graduate Program, University of California, Riverside, Riverside, CA, United States
| | - Linh M. Vuong
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Jane R. Evans
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Songqin Pan
- Proteomics Core, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, United States
| | - Johannes Fahrmann
- National Institutes of Health West Coast Metabolomics Center, University of California, Davis, Davis, CA, United States
| | - Jun Yang
- Department of Entomology and Nematology & UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA, United States
| | - Bruce D. Hammock
- Department of Entomology and Nematology & UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA, United States
| | - Oliver Fiehn
- National Institutes of Health West Coast Metabolomics Center, University of California, Davis, Davis, CA, United States
| | - Baharan Fekry
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center (UT Health), Houston, TX, United States
| | - Kristin Eckel-Mahan
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center (UT Health), Houston, TX, United States
- Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center (UT Health), Houston, TX, United States
| | - Frances M. Sladek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
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Targeting mitochondrial impairment for the treatment of cardiovascular diseases: From hypertension to ischemia-reperfusion injury, searching for new pharmacological targets. Biochem Pharmacol 2023; 208:115405. [PMID: 36603686 DOI: 10.1016/j.bcp.2022.115405] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023]
Abstract
Mitochondria and mitochondrial proteins represent a group of promising pharmacological target candidates in the search of new molecular targets and drugs to counteract the onset of hypertension and more in general cardiovascular diseases (CVDs). Indeed, several mitochondrial pathways result impaired in CVDs, showing ATP depletion and ROS production as common traits of cardiac tissue degeneration. Thus, targeting mitochondrial dysfunction in cardiomyocytes can represent a successful strategy to prevent heart failure. In this context, the identification of new pharmacological targets among mitochondrial proteins paves the way for the design of new selective drugs. Thanks to the advances in omics approaches, to a greater availability of mitochondrial crystallized protein structures and to the development of new computational approaches for protein 3D-modelling and drug design, it is now possible to investigate in detail impaired mitochondrial pathways in CVDs. Furthermore, it is possible to design new powerful drugs able to hit the selected pharmacological targets in a highly selective way to rescue mitochondrial dysfunction and prevent cardiac tissue degeneration. The role of mitochondrial dysfunction in the onset of CVDs appears increasingly evident, as reflected by the impairment of proteins involved in lipid peroxidation, mitochondrial dynamics, respiratory chain complexes, and membrane polarization maintenance in CVD patients. Conversely, little is known about proteins responsible for the cross-talk between mitochondria and cytoplasm in cardiomyocytes. Mitochondrial transporters of the SLC25A family, in particular, are responsible for the translocation of nucleotides (e.g., ATP), amino acids (e.g., aspartate, glutamate, ornithine), organic acids (e.g. malate and 2-oxoglutarate), and other cofactors (e.g., inorganic phosphate, NAD+, FAD, carnitine, CoA derivatives) between the mitochondrial and cytosolic compartments. Thus, mitochondrial transporters play a key role in the mitochondria-cytosol cross-talk by leading metabolic pathways such as the malate/aspartate shuttle, the carnitine shuttle, the ATP export from mitochondria, and the regulation of permeability transition pore opening. Since all these pathways are crucial for maintaining healthy cardiomyocytes, mitochondrial carriers emerge as an interesting class of new possible pharmacological targets for CVD treatments.
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Insight into the Mammalian Aquaporin Interactome. Int J Mol Sci 2022; 23:ijms23179615. [PMID: 36077012 PMCID: PMC9456110 DOI: 10.3390/ijms23179615] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 01/07/2023] Open
Abstract
Aquaporins (AQPs) are a family of transmembrane water channels expressed in all living organisms. AQPs facilitate osmotically driven water flux across biological membranes and, in some cases, the movement of small molecules (such as glycerol, urea, CO2, NH3, H2O2). Protein-protein interactions play essential roles in protein regulation and function. This review provides a comprehensive overview of the current knowledge of the AQP interactomes and addresses the molecular basis and functional significance of these protein-protein interactions in health and diseases. Targeting AQP interactomes may offer new therapeutic avenues as targeting individual AQPs remains challenging despite intense efforts.
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Clavere NG, Alqallaf A, Rostron KA, Parnell A, Mitchell R, Patel K, Boateng SY. Inhibition of activin A receptor signalling attenuates age-related pathological cardiac remodelling. Dis Model Mech 2022; 15:275323. [PMID: 35380160 PMCID: PMC9118092 DOI: 10.1242/dmm.049424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/16/2022] [Indexed: 11/20/2022] Open
Abstract
In the heart, ageing is associated with DNA damage, oxidative stress, fibrosis and activation of the activin signalling pathway, leading to cardiac dysfunction. The cardiac effects of activin signalling blockade in progeria are unknown. This study investigated the cardiac effects of progeria induced by attenuated levels of Ercc1, which is required for DNA excision and repair, and the impact of activin signalling blockade using a soluble activin receptor type IIB (sActRIIB). DNA damage and oxidative stress were significantly increased in Ercc1Δ/− hearts, but were reduced by sActRIIB treatment. sActRIIB treatment improved cardiac systolic function and induced cardiomyocyte hypertrophy in Ercc1Δ/− hearts. RNA-sequencing analysis showed that in Ercc1Δ/− hearts, there was an increase in pro-oxidant and a decrease in antioxidant gene expression, whereas sActRIIB treatment reversed this effect. Ercc1Δ/− hearts also expressed higher levels of anti-hypertrophic genes and decreased levels of pro-hypertrophic ones, which were also reversed by sActRIIB treatment. These results show for the first time that inhibition of activin A receptor signalling attenuates cardiac dysfunction, pathological tissue remodelling and gene expression in Ercc1-deficient mice and presents a potentially novel therapeutic target for heart diseases. Summary: Attenuated DNA repair is associated with pathological cardiac remodelling and gene expression. Much of this phenotype is attenuated by inhibition of the activin signalling pathway using soluble activin receptor treatment.
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Affiliation(s)
- Nicolas G Clavere
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
| | - Ali Alqallaf
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
| | - Kerry A Rostron
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, Commonwealth Building, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Andrew Parnell
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
| | - Robert Mitchell
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
| | - Ketan Patel
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
| | - Samuel Y Boateng
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, Health and Life Sciences Building, University of Reading, Whiteknights, Reading RG6 6UB, UK
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Galli M, Hameed A, Żbikowski A, Zabielski P. Aquaporins in insulin resistance and diabetes: More than channels! Redox Biol 2021; 44:102027. [PMID: 34090243 PMCID: PMC8182305 DOI: 10.1016/j.redox.2021.102027] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/09/2021] [Accepted: 05/24/2021] [Indexed: 12/12/2022] Open
Abstract
Aquaporins (AQPs) are part of the family of the integral membrane proteins. Their function is dedicated to the transport of water, glycerol, ammonia, urea, H2O2, and other small molecules across the biological membranes. Although for many years they were scarcely considered, AQPs have a relevant role in the development of many diseases. Recent discoveries suggest, that AQPs may play an important role in the process of fat accumulation and regulation of oxidative stress, two crucial aspects of insulin resistance and type-2 diabetes (T2D). Insulin resistance (IR) and T2D are multi-faceted systemic diseases with multiple connections to obesity and other comorbidities such as hypertension, dyslipidemia and metabolic syndrome. Both IR and T2D transcends different tissues and organs, creating the maze of mutual relationships between adipose fat depots, skeletal muscle, liver and other insulin-sensitive organs. AQPs with their heterogenous properties, distinctive tissue distribution and documented involvement in both the lipid metabolism and regulation of the oxidative stress appear to be feasible candidates in the search for the explanation to this third-millennium plague. A lot of research has been assigned to adipose tissue AQP7 and liver tissue AQP9, clarifying their relationship and coordinated work in the induction of hepatic insulin resistance. Novel research points also to other aquaporins, such as AQP11 which may be associated with the induction of insulin resistance and T2D through its involvement in hydrogen peroxide transport. In this review we collected recent discoveries in the field of AQP's involvement in the insulin resistance and T2D. Novel paths which connect AQPs with metabolic disorders can give new fuel to the research on obesity, insulin resistance and T2D - one of the most worrying problems of the modern society. Presentation of the current knowledge on the involvement of aquaporins in disease state. Overview on latest research regarding insulin resistance and AQPs. Conceptualisation of an AQPs network involved regulation of lipid-related metabolism.
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Affiliation(s)
- Mauro Galli
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Ahsan Hameed
- Clinical Research Center, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Arkadiusz Żbikowski
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
| | - Piotr Zabielski
- Department of Medical Biology, Medical University of Bialystok, 15-089, Bialystok, Poland.
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Schnabel B, Kuhrt H, Wiedemann P, Bringmann A, Hollborn M. Osmotic regulation of aquaporin-8 expression in retinal pigment epithelial cells in vitro: Dependence on K ATP channel activation. Mol Vis 2020; 26:797-817. [PMID: 33456300 PMCID: PMC7803296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 12/28/2020] [Indexed: 12/02/2022] Open
Abstract
PURPOSE The expression of aquaporin-8 (AQP8), which plays a crucial role in the maintenance of the cellular fluid and electrolyte balance, was shown to be increased in RPE cells under hyperosmotic conditions. The aim of the present study was to investigate the mechanisms of hyperosmotic AQP8 gene expression and the localization of AQP8 in cultured human RPE cells. METHODS Hyperosmolarity was produced with the addition of 100 mM NaCl or 200 mM sucrose. Hypoxia was induced by cell culture in a 0.2% O2 atmosphere or the addition of the hypoxia mimetic CoCl2. Oxidative stress was induced by the addition of H2O2. Gene expression was determined with real-time RT-PCR analysis. AQP8 protein localization and secretion of VEGF were evaluated with immunocytochemistry, western blotting, and enzyme-linked immunosorbent assay (ELISA). RESULTS Immunocytochemical and western blot data suggest that the AQP8 protein is mainly located in the mitochondria. Extracellular hyperosmolarity, hypoxia, and oxidative stress induced increases in AQP8 gene expression. Hyperosmotic AQP8 gene expression was reduced by inhibitors of the p38 MAPK and PI3K signal transduction pathways, and by JAK2 and PLA2 inhibitors, and was in part mediated by the transcriptional activity of CREB. Hyperosmotic AQP8 gene expression was also reduced by autocrine/paracrine interleukin-1 signaling, the sulfonylureas glibenclamide and glipizide, which are known inhibitors of KATP channel activation, and a pannexin-blocking peptide. The KATP channel opener pinacidil increased the expression of AQP8 under control conditions. The cells contained Kir6.1 and SUR2B gene transcripts and displayed Kir6.1 immunoreactivity. siRNA-mediated knockdown of AQP8 caused increases in hypoxic VEGF gene expression and secretion and decreased cell viability under control, hyperosmotic, and hypoxic conditions. CONCLUSIONS The data indicate that hyperosmotic expression of AQP8 in RPE cells is dependent on the activation of KATP channels. The data suggest that AQP8 activity decreases the hypoxic VEGF expression and improves the viability of RPE cells which may have impact for ischemic retinal diseases like diabetic retinopathy and age-related macular degeneration.
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Affiliation(s)
- Benjamin Schnabel
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, Medical Faculty, University of Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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9
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Cell organelles as targets of mammalian cadmium toxicity. Arch Toxicol 2020; 94:1017-1049. [PMID: 32206829 DOI: 10.1007/s00204-020-02692-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Ever increasing environmental presence of cadmium as a consequence of industrial activities is considered a health hazard and is closely linked to deteriorating global health status. General animal and human cadmium exposure ranges from ingestion of foodstuffs sourced from heavily polluted hotspots and cigarette smoke to widespread contamination of air and water, including cadmium-containing microplastics found in household water. Cadmium is promiscuous in its effects and exerts numerous cellular perturbations based on direct interactions with macromolecules and its capacity to mimic or displace essential physiological ions, such as iron and zinc. Cell organelles use lipid membranes to form complex tightly-regulated, compartmentalized networks with specialized functions, which are fundamental to life. Interorganellar communication is crucial for orchestrating correct cell behavior, such as adaptive stress responses, and can be mediated by the release of signaling molecules, exchange of organelle contents, mechanical force generated through organelle shape changes or direct membrane contact sites. In this review, cadmium effects on organellar structure and function will be critically discussed with particular consideration to disruption of organelle physiology in vertebrates.
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10
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Cuillerier A, Honarmand S, Cadete VJJ, Ruiz M, Forest A, Deschênes S, Beauchamp C, Charron G, Rioux JD, Des Rosiers C, Shoubridge EA, Burelle Y. Loss of hepatic LRPPRC alters mitochondrial bioenergetics, regulation of permeability transition and trans-membrane ROS diffusion. Hum Mol Genet 2018; 26:3186-3201. [PMID: 28575497 DOI: 10.1093/hmg/ddx202] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/19/2017] [Indexed: 12/19/2022] Open
Abstract
The French-Canadian variant of Leigh Syndrome (LSFC) is an autosomal recessive oxidative phosphorylation (OXPHOS) disorder caused by a mutation in LRPPRC, coding for a protein involved in the stability of mitochondrially-encoded mRNAs. Low levels of LRPPRC are present in all patient tissues, but result in a disproportionately severe OXPHOS defect in the brain and liver, leading to unpredictable subacute metabolic crises. To investigate the impact of the OXPHOS defect in the liver, we analyzed the mitochondrial phenotype in mice harboring an hepatocyte-specific inactivation of Lrpprc. Loss of LRPPRC in the liver caused a generalized growth delay, and typical histological features of mitochondrial hepatopathy. At the molecular level, LRPPRC deficiency caused destabilization of polyadenylated mitochondrial mRNAs, altered mitochondrial ultrastructure, and a severe complex IV (CIV) and ATP synthase (CV) assembly defect. The impact of LRPPRC deficiency was not limited to OXPHOS, but also included impairment of long-chain fatty acid oxidation, a striking dysregulation of the mitochondrial permeability transition pore, and an unsuspected alteration of trans-membrane H2O2 diffusion, which was traced to the ATP synthase assembly defect, and to changes in the lipid composition of mitochondrial membranes. This study underscores the value of mitochondria phenotyping to uncover complex and unexpected mechanisms contributing to the pathophysiology of mitochondrial disorders.
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Affiliation(s)
| | - Shamisa Honarmand
- Department of Human Genetics, Montreal Neurological Institute McGill University, Montreal, QC H3A 2B4, Canada
| | | | - Matthieu Ruiz
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Anik Forest
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Sonia Deschênes
- Faculty of Pharmacy, University of Montreal, Montreal, QC H3C 3J7, Canada.,Faculty of Medicine and Department of Nutrition, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | | | | | - Guy Charron
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - John D Rioux
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Christine Des Rosiers
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada.,Faculty of Medicine and Department of Nutrition, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, Montreal Neurological Institute McGill University, Montreal, QC H3A 2B4, Canada
| | - Yan Burelle
- Faculty of Pharmacy, University of Montreal, Montreal, QC H3C 3J7, Canada
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