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Li B, Jiang L, Martis RM, Siemerink MJ, Van Severen V, Cunningham WJ, Donaldson PJ, Lim JC. Ascorbic acid export from human donor lenses: Is the lens a source of ascorbic acid in the ocular humors? Exp Eye Res 2024; 245:109972. [PMID: 38871164 DOI: 10.1016/j.exer.2024.109972] [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: 04/08/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/15/2024]
Abstract
In previous work, we have shown that the lens acts a reservoir of the antioxidant glutathione (GSH), capable of exporting this antioxidant into the ocular humors and potentially protecting the tissues of the eye that interface with these humors from oxidative stress. In this study, we have extended this work by examining whether the lens acts as a source of ascorbic acid (AsA) to maintain the high levels of AsA known to be present in the ocular humors either by the direct export of AsA into the humors and/or by functioning as a recycling site for AsA, via the direct uptake of oxidised ascorbate (DHA) from the humors, its regeneration to AsA in the lens and then its subsequent export back into the humors. To test this, human lenses of varying ages were cultured for 1 h under hypoxic conditions and AsA/DHA levels measured in the media and in the lens. Human lenses were also cultured in compartmentalised chambers to determine whether efflux of AsA/DHA occurs at the anterior or posterior surface. Immunohistochemistry was performed on human donor lenses and sections labelled with antibodies against GLUT1, a putative DHA uptake transporter. Vitreous humor was collected from patients undergoing vitrectomy who either had a natural clear lens, an artificial intraocular implant (IOL) or a cataractous lens, and AsA/DHA and GSH and oxidised GSH (GSSG) measured. We found that cultured human donor lenses released both AsA and DHA into the media. Culturing of lenses in a compartmentalised chamber revealed that AsA and DHA efflux occurs at both surfaces, with relatively equal amounts of AsA and DHA released from each surface. The posterior surface of the lens was shown to express the GLUT1 transporter. Analysis of vitreous samples from patients undergoing vitrectomy revealed that vitreous GSH and AsA levels were similar between the natural lens group, IOL and cataractous lens group. Taken together, while human donor lenses were shown to export AsA and DHA into the surrounding media, the amount of AsA and DHA released from donor lenses was low and not sufficient to sustain the high levels of total AsA normally present in the humors. This suggests that although the lens is not the main source for maintaining high levels of AsA in the ocular humors, the lens may help to support local AsA levels close to the lens.
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Affiliation(s)
- Bo Li
- Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand; New Zealand-National Eye Centre, University of Auckland, New Zealand
| | - Lanpeng Jiang
- Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand; New Zealand-National Eye Centre, University of Auckland, New Zealand
| | - Renita M Martis
- Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand; New Zealand-National Eye Centre, University of Auckland, New Zealand.
| | - Martin J Siemerink
- Auckland District Health Board, Greenlane Clinical Centre, Auckland, New Zealand
| | - Veerle Van Severen
- Auckland District Health Board, Greenlane Clinical Centre, Auckland, New Zealand
| | - William J Cunningham
- New Zealand-National Eye Centre, University of Auckland, New Zealand; Auckland District Health Board, Greenlane Clinical Centre, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand; New Zealand-National Eye Centre, University of Auckland, New Zealand
| | - Julie C Lim
- Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand; New Zealand-National Eye Centre, University of Auckland, New Zealand.
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2
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Martis RM, Grey AC, Wu H, Wall GM, Donaldson PJ, Lim JC. N-Acetylcysteine amide (NACA) and diNACA inhibit H 2O 2-induced cataract formation ex vivo in pig and rat lenses. Exp Eye Res 2023; 234:109610. [PMID: 37536438 DOI: 10.1016/j.exer.2023.109610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Oxidative stress plays a central role in cataract formation suggesting that antioxidants might slow cataract progression. The anticataract activity of N-acetylcysteine amide (NACA) and (2 R, 2 R')-3,3'-disulfanediyl bis(2-acetamidopropanamide) (diNACA) and/or N-acetylcysteine (NAC), were evaluated in porcine and rat lens models. Cataractogenesis via oxidation was induced with H2O2 and/or glucose oxidase (GO). Porcine lenses were incubated in 0.1 mM, 1 mM, or 10 mM NAC, NACA or diNACA for 24 h. Lenses were then transferred to media containing 0.75 mM H2O2 and 4.63U of GO in order to maintain a constant H2O2 level for an additional 8 h. At the end of incubation, lenses were imaged under darkfield microscopy. Separately, rat lenses were extracted from 3-week-old Wistar rats and incubated with either 10 mM NACA or 10 mM diNACA for 24 h prior to treatment with 0.2U GO to generate a steady source of ∼0.6 mM H2O2. Rat lenses were analyzed by LC-MS/MS to quantify changes in cysteine, cystine, glutathione (GSH) or oxidised glutathione (GSSG) levels in the lens epithelium, cortex or core. Pre-treatment with NACA or diNACA followed by oxidation with H2O2 and/or GO to stimulate cataract formation afforded rapid assessment in ex vivo porcine (32 h) and rat (48 h) lens models. Pre-treatment of isolated porcine lenses with 0.1 mM, 1 mM or 10 mM of either NAC, NACA or diNACA followed by H2O2/GO treatment resulted in reduced lens opacity relative to the lenses exposed to H2O2/GO, with NACA and diNACA reducing opacities to a greater extent than NAC. Rat lenses incubated with 10 mM NACA or 10 mM diNACA without exposure to H2O2 showed no signs of opacities. Pre-treatment of rat lenses with 10 mM NACA or 10 mM diNACA, followed by GO cataract induction resulted in reduced opacities compared to control (GO alone). LC-MS/MS analyses revealed that NACA, but not diNACA, increased cysteine, cystine and GSH levels in rat lens epithelium and cortex regions. Taken together, both NACA and diNACA inhibited cataract formation to a greater extent than NAC (all at 1-10 mM) in an ex vivo porcine lens model. Both NACA and diNACA (both at 10 mM) reduced cataract formation in rat lenses. Based on LC-MS/MS analyses, NACA-induced reduction in opacity observed in rat lenses was attributed to enhanced cysteine and GSH levels while the diNACA-induced reduction in opacity induced did not consistently increase cysteine, cystine and GSH levels and, therefore, appears to involve a different antioxidant mechanism. These screening studies warrant further testing of NACA and diNACA as anticataract agents.
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Affiliation(s)
- R M Martis
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - A C Grey
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - H Wu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, Texas, 76107, USA; North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, Texas, 76107, USA
| | - G M Wall
- Nacuity Pharmaceuticals, PTY LTD, a Subsidiary of Nacuity Pharmaceuticals, Inc., 306 W 7th St., Ste 310, Fort Worth, TX, 76102, USA
| | - P J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - J C Lim
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
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3
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Regulation of lens water content: Effects on the physiological optics of the lens. Prog Retin Eye Res 2022:101152. [DOI: 10.1016/j.preteyeres.2022.101152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/09/2022]
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4
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Hayanti SY, Sholikin MM, Jayanegara A, Ulum MF, da Costa MA, Fitriawaty F, Surya S, Hadiatry MC, Asmarasari SA, Handiwirawan E, Anggraeny YN, Rohaeni ES, Ahmad SN, Bustami B, Aryogi A, Pamungkas D, Yusriani Y. Effect of supplementing L-cysteine and its group analogs on frozen semen quality of bulls: A meta-analysis. Vet World 2022; 15:2517-2524. [PMID: 36590123 PMCID: PMC9798054 DOI: 10.14202/vetworld.2022.2517-2524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 09/19/2022] [Indexed: 11/11/2022] Open
Abstract
Background and Aim The quality of frozen bull sperm after thawing is influenced by the primary diluent and antioxidant. This meta-analysis was conducted to determine the effect of supplementing L-cysteine and its group analogs on the quality of frozen bull sperm. Materials and Methods A total of 22 articles obtained from Google Scholar and Scopus were integrated into metadata. The effects of adding L-cysteine and its analogs (e.g., cysteine HCl and N-acetyl-L-cysteine), both of which are known as L-cysteine, were evaluated in this meta-analysis. The following parameters were examined: Abnormality, acrosome damage, acrosomal integrity, DNA damage, DNA integrity, malondialdehyde (MDA) content, plasma membrane integrity, pregnancy rate, progressive motility, sperm viability, and total motility. Data were analyzed using the mixed model methodology, with L-cysteine dosage as a fixed effect and different studies as random effects. Results L-cysteine supplementation significantly increased the total motility (p < 0.05) and MDA content of semen, following a linear pattern. Progressive motility, acrosomal integrity, and plasma membrane integrity were significantly increased, showing a quadratic pattern (p < 0.05). Abnormality and acrosome damage were significantly decreased (p < 0.05), following a quadratic and linear pattern, respectively. Other parameters remained unaffected by L-cysteine supplementation. L-cysteine and cysteine HCl significantly inhibited (p = 0.001) acrosome damage in thawed frozen sperm compared with control sperm. Conclusion Supplementing L-cysteine and its analog groups are recommended for freezing bull semen as it generally improves sperm quality.
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Affiliation(s)
- Sari Yanti Hayanti
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia,Corresponding author: Sari Yanti Hayanti, e-mail: Co-authors: MMS: , AJ: , MFU: , MAC: , FF: , SS: , MCH: , SAA: , EH: , YNA: , ESR: , SNA: , BB: , AA: , DP: , YY:
| | - Mohammad Miftakhus Sholikin
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia,Animal Feed and Nutrition Modelling Research Group, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia
| | - Anuraga Jayanegara
- Animal Feed and Nutrition Modelling Research Group, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia,Department of Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia
| | - Mokhamad Fakhrul Ulum
- Division of Veterinary Reproduction, Obstetrics, and Gynaecology, Department of Veterinary Clinic, Reproduction, and Pathology, School of Veterinary Medicine and Biomedical Sciences, IPB University, Bogor, 16680, West Java, Indonesia
| | - Marchie Astrid da Costa
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Fitriawaty Fitriawaty
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Surya Surya
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Maureen Chrisye Hadiatry
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Santiananda Arta Asmarasari
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Eko Handiwirawan
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Yenny Nur Anggraeny
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Eni Siti Rohaeni
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Salfina Nurdin Ahmad
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Bustami Bustami
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Aryogi Aryogi
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Dicky Pamungkas
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Yenni Yusriani
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
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Lou MF. Glutathione and Glutaredoxin in Redox Regulation and Cell Signaling of the Lens. Antioxidants (Basel) 2022; 11:1973. [PMID: 36290696 PMCID: PMC9598519 DOI: 10.3390/antiox11101973] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
The ocular lens has a very high content of the antioxidant glutathione (GSH) and the enzymes that can recycle its oxidized form, glutathione disulfide (GSSG), for further use. It can be synthesized in the lens and, in part, transported from the neighboring anterior aqueous humor and posterior vitreous body. GSH is known to protect the thiols of the structural lens crystallin proteins from oxidation by reactive oxygen species (ROS) so the lens can maintain its transparency for proper visual function. Age-related lens opacity or senile cataract is the major visual impairment in the general population, and its cause is closely associated with aging and a constant exposure to environmental oxidative stress, such as ultraviolet light and the metabolic end product, H2O2. The mechanism for senile cataractogenesis has been hypothesized as the results of oxidation-induced protein-thiol mixed disulfide formation, such as protein-S-S-glutathione and protein-S-S-cysteine mixed disulfides, which if not reduced in time, can change the protein conformation to allow cascading modifications of various kinds leading to protein-protein aggregation and insolubilization. The consequence of such changes in lens structural proteins is lens opacity. Besides GSH, the lens has several antioxidation defense enzymes that can repair oxidation damage. One of the specific redox regulating enzymes that has been recently identified is thioltransferase (glutaredoxin 1), which works in concert with GSH, to reduce the oxidative stress as well as to regulate thiol/disulfide redox balance by preventing protein-thiol mixed disulfide accumulation in the lens. This oxidation-resistant and inducible enzyme has multiple physiological functions. In addition to protecting structural proteins and metabolic enzymes, it is able to regulate the redox signaling of the cells during growth factor-stimulated cell proliferation and other cellular functions. This review article focuses on describing the redox regulating functions of GSH and the thioltransferase enzyme in the ocular lens.
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Affiliation(s)
- Marjorie F. Lou
- School of Veterinary Medicine and Biomedical Sciences, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
- Department of Ophthalmology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Pharmaceutical Sciences, System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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6
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Martis RM, Li B, Donaldson PJ, Lim JCH. Early Onset of Age-Related Cataracts in Cystine/Glutamate Antiporter Knockout Mice. Invest Ophthalmol Vis Sci 2021; 62:23. [PMID: 34156426 PMCID: PMC8237109 DOI: 10.1167/iovs.62.7.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose The purpose of this study was to determine the importance of the xCT is a subunit. The cystine/glutamate antiporter is actually system xc-xCT subunit of the cystine/glutamate antiporter in maintaining redox balance by investigating the effects of the loss of xCT on lens transparency and cystine/cysteine balance in the aqueous humour. Methods C57Bl/6 wild-type and xCT knockout mice at five age groups (6 weeks to 12 months) were used. Lens transparency was examined using a slit-lamp and morphological changes visualized by immunolabelling and confocal microscopy. Quantification of glutathione in lenses and cysteine and cystine levels in the aqueous was conducted by liquid chromatography tandem mass spectrometry (LC-MS/MS). Results Slit-lamp examinations revealed that 3-month-old wild-type mice and xCT knockout mice lenses exhibited an anterior localized cataract. The frequency of this cataract significantly increased in the knockout mice compared to the wild-type mice. Morphological studies revealed a localized swelling of the lens fiber cells at the anterior pole. Glutathione levels in whole lenses were similar between wild-type and knockout mice. However, glutathione levels were significantly decreased at 3 months in the knockout mice in the lens epithelium compared to the wild-type mice. Aqueous cysteine levels remained similar between wild-type and knockout mice at all age groups, whereas cystine levels were significantly increased in 3-, 9-, and 12-month-old knockout mice compared to wild-type mice. Conclusions Loss of xCT resulted in the depletion of glutathione in the epithelium and an oxidative shift in the cysteine/cystine ratio of the aqueous. Together, these oxidative changes may contribute to the accelerated development of an anterior cataract in knockout mice, which appears to be a normal feature of aging in wild-type mice.
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Affiliation(s)
- Renita Maria Martis
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Bo Li
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Paul James Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Julie Ching-Hsia Lim
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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7
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Wu J, Yeung SCJ, Liu S, Qdaisat A, Jiang D, Liu W, Cheng Z, Liu W, Wang H, Li L, Zhou Z, Liu R, Yang C, Chen C, Yang R. Cyst(e)ine in nutrition formulation promotes colon cancer growth and chemoresistance by activating mTORC1 and scavenging ROS. Signal Transduct Target Ther 2021; 6:188. [PMID: 34045438 PMCID: PMC8160199 DOI: 10.1038/s41392-021-00581-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/22/2023] Open
Abstract
Weight loss and cachexia are common problems in colorectal cancer patients; thus, parenteral and enteral nutrition support play important roles in cancer care. However, the impact of nonessential amino acid components of nutritional intake on cancer progression has not been fully studied. In this study, we discovered that gastrointestinal cancer patients who received cysteine as part of the parenteral nutrition had shorter overall survival (P < 0.001) than those who did not. Cystine indeed robustly promotes colon cancer cell growth in vitro and in immunodeficient mice, predominately by inhibiting SESN2 transcription via the GCN2-ATF4 axis, resulting in mTORC1 activation. mTORC1 inhibitors Rapamycin and Everolimus block cystine-induced cancer cell proliferation. In addition, cystine confers resistance to oxaliplatin and irinotecan chemotherapy by quenching chemotherapy-induced reactive oxygen species via synthesizing glutathione. We demonstrated that dietary deprivation of cystine suppressed colon cancer xenograft growth without weight loss in mice and boosted the antitumor effect of oxaliplatin. These findings indicate that cyst(e)ine, as part of supplemental nutrition, plays an important role in colorectal cancer and manipulation of cyst(e)ine content in nutritional formulations may optimize colorectal cancer patient survival.
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Affiliation(s)
- Jiao Wu
- Department of the Second Medical Oncology, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Sai-Ching Jim Yeung
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sicheng Liu
- Department of the Second Medical Oncology, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China
| | - Aiham Qdaisat
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Dewei Jiang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Wenli Liu
- Department of Palliative, Rehabilitation and Integrative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Zhuo Cheng
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Wenjing Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Haixia Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Lu Li
- Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Zhongmei Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Rong Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Chuanyu Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Ceshi Chen
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China. .,KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China. .,Institute of Translation Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China.
| | - Runxiang Yang
- Department of the Second Medical Oncology, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, China.
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Zhou N, Huo F, Yue Y, Ma K, Yin C. Rearrangement regulated cysteine fluorescent probe for cellular oxidative stress evaluation induced by copper(II). CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2020.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Identification, Expression, and Roles of the Cystine/Glutamate Antiporter in Ocular Tissues. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:4594606. [PMID: 32655769 PMCID: PMC7320271 DOI: 10.1155/2020/4594606] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/21/2020] [Indexed: 01/21/2023]
Abstract
The cystine/glutamate antiporter (system x c -) is composed of a heavy chain subunit 4F2hc linked by a disulphide bond to a light chain xCT, which exchanges extracellular cystine, the disulphide form of the amino acid cysteine, for intracellular glutamate. In vitro research in the brain, kidney, and liver have shown this antiporter to play a role in minimising oxidative stress by providing a source of intracellular cysteine for the synthesis of the antioxidant glutathione. In vivo studies using the xCT knockout mouse revealed that the plasma cystine/cysteine redox couple was tilted to a more oxidative state demonstrating system xc - to also play a role in maintaining extracellular redox balance by driving a cystine/cysteine redox cycle. In addition, through import of cystine, system xc - also serves to export glutamate into the extracellular space which may influence neurotransmission and glutamate signalling in neural tissues. While changes to system xc - function has been linked to cancer and neurodegenerative disease, there is limited research on the roles of system xc - in the different tissues of the eye, and links between the antiporter, aging, and ocular disease. Hence, this review seeks to consolidate research on system xc - in the cornea, lens, retina, and ocular humours conducted across several species to shed light on the in vitro and in vivo roles of xCT in the eye and highlight the utility of the xCT knockout mouse as a tool to investigate the contribution of xCT to age-related ocular diseases.
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Lim JC, Grey AC, Zahraei A, Donaldson PJ. Age‐dependent changes in glutathione metabolism pathways in the lens: New insights into therapeutic strategies to prevent cataract formation—A review. Clin Exp Ophthalmol 2020; 48:1031-1042. [DOI: 10.1111/ceo.13801] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/15/2020] [Accepted: 05/22/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Julie C. Lim
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center University of Auckland Auckland New Zealand
| | - Angus C. Grey
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center University of Auckland Auckland New Zealand
| | - Ali Zahraei
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center University of Auckland Auckland New Zealand
| | - Paul J. Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center University of Auckland Auckland New Zealand
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11
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Xie X, Huo F, Yue Y, Chao J, Yin C. NEM assisted real-time fluorescence detection of Cys in cytoplasm and mice imaging by a Coumarin probe containing carboxyl group. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 225:117517. [PMID: 31521001 DOI: 10.1016/j.saa.2019.117517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 07/29/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Alterations of the homeostasis balance of cysteine (Cys) are associated with a variety of diseases and cellular functions, and therefore, Cys dynamic real-time living cell intracellular imaging and quantification are important for understanding the pathophysiological processes. Thus, Cys probe that can permeate high efficiently is the first one to be affected. In fact, it is difficult for organic molecular probes to infiltrate cells because of the unique structure of the cell membrane. In this work, we found that probe containing-carboxyl just stagnated in cytomembrane due to carboxyl of probe and amino group of membrane protein forming peptide chains, nevertheless, the addition of NEM, improved membrane permeability by NEM reacting with sulfhydryl of membrane protein, which made probe permeate high efficiently and sequentially real-time detect the Cys in cytoplasm. It is the first time noted that NEM can regulate Cys probe containing-carboxyl for high efficient detection in cytoplasm. Additionally, probe was successfully applied to image Cys in mouse.
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Affiliation(s)
- Xixi Xie
- Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000, Shanxi, China; Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Fangjun Huo
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China
| | - Yongkang Yue
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Jianbin Chao
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China
| | - Caixia Yin
- Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000, Shanxi, China; Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
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12
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Martis RM, Donaldson PJ, Li B, Middleditch M, Kallingappa PK, Lim JC. Mapping of the cystine-glutamate exchanger in the mouse eye: a role for xCT in controlling extracellular redox balance. Histochem Cell Biol 2019; 152:293-310. [PMID: 31396687 DOI: 10.1007/s00418-019-01805-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2019] [Indexed: 12/13/2022]
Abstract
The cystine-glutamate exchanger (system xc-) is responsible for the exchange of extracellular cystine for intracellular glutamate. In this study, we mapped the expression of xCT, the light chain subunit of system xc- in the different tissues of 3-6-week-old mouse (C57BL/6J) eye and have used an xCT knockout mouse to verify labelling specificity. Moreover, using the xCT knockout mouse, we investigated whether xCT was involved in maintaining extracellular redox balance in the eye. xCT transcript and protein were present in the cornea, lens and retina of wild-type mice, but not knockout mice. xCT was localised to the corneal epithelium, and the lens epithelium and cortical fibre cells but was absent in the iris. xCT localisation could not be determined in the ciliary body or retina, since xCT labelling was also detected in the knockout indicating a lack of specificity of the xCT antibody in tissues of a neural origin. Intracellular cysteine and cystine concentrations were similar in the wild-type and xCT knockout mouse for the cornea, lens, and retina. While extracellular cysteine levels were similar between the plasma, aqueous humour, and vitreous humour of the wild-type and xCT knockout mouse, extracellular cystine levels in the plasma and aqueous were significantly elevated in the xCT knockout mouse relative to the wild type. This suggests that loss of xCT results in an increased oxidative environment, particularly within the anterior chamber of the eye in which the aqueous humour resides. How this oxidative shift impacts ocular tissues that interface with the aqueous humour over time will be the focus of future work.
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Affiliation(s)
- Renita M Martis
- Department of Physiology, School of Medical and Health Sciences, University of Auckland, Auckland, 1023, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand.,NZ National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical and Health Sciences, University of Auckland, Auckland, 1023, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand.,NZ National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Bo Li
- Department of Physiology, School of Medical and Health Sciences, University of Auckland, Auckland, 1023, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand.,NZ National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Martin Middleditch
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Prasanna K Kallingappa
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand.,School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Julie C Lim
- Department of Physiology, School of Medical and Health Sciences, University of Auckland, Auckland, 1023, New Zealand. .,School of Medical Sciences, University of Auckland, Auckland, New Zealand. .,NZ National Eye Centre, University of Auckland, Auckland, New Zealand.
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13
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Martis RM, Donaldson PJ, Lim JC. Corneal opacities in mice exposed to repeated contact procedures during ocular examinations. Clin Exp Optom 2019; 103:307-311. [PMID: 31218744 DOI: 10.1111/cxo.12934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/10/2019] [Accepted: 05/23/2019] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Cystine/glutamate exchanger (xCT) knockout mice are reported to exhibit an oxidative shift in the plasma cystine/cysteine ratio reminiscent of that seen in human plasma of ageing individuals. This suggests that the xCT knockout mouse is a model of accelerated ageing. The aim of this study was to examine the progression of age-related pathologies in the ocular tissues of wild-type mice and compare this to the xCT knockout mice. METHODS Wild-type and xCT knockout mice were examined longitudinally or as separate groups of animals at six weeks, three months, six months, nine months, and 12 months of age. All groups of mice were anaesthetised, intraocular pressure measured using the iCare TONOLAB rebound tonometer and eyes examined using the Micron IV system. RESULTS While the aim of the study was to determine if xCT knockout mice developed age-related pathologies earlier than wild-type mice, it was inadvertently discovered in the longitudinal cohort of animals, that the eyes developed corneal lesions in both groups of animals by six months of age, which obscured examination of the lens and retina. These lesions were not characteristic of age-related pathologies, but rather due to an external stressor. Lesions in the xCT knockout mice developed at an earlier age compared to wild-type mice, suggesting that loss of xCT exacerbates damage to the cornea, most likely caused by the rebound tonometer. When the same ocular procedures were performed on separate cohorts of mice of specific ages, no corneal lesions were detected for both groups of mice. CONCLUSIONS While it may seem advantageous to examine the same cohort of mice to monitor the development of age-related pathologies, the type of ophthalmic tests conducted needs to be carefully considered to avoid introducing pathologies that are inadvertently a result of the examination process itself.
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Affiliation(s)
- Renita M Martis
- Department of Physiology, School of Medical Sciences, and New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, and New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Julie C Lim
- Department of Physiology, School of Medical Sciences, and New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
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14
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Ono K, Furugen A, Kurosawa Y, Jinno N, Narumi K, Kobayashi M, Iseki K. Analysis of the effects of polyunsaturated fatty acids on transporter expressions using a PCR array: Induction of xCT/SLC7A11 in human placental BeWo cells. Placenta 2018; 75:34-41. [PMID: 30712664 DOI: 10.1016/j.placenta.2018.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/04/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Polyunsaturated fatty acids (PUFAs), including arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are essential for adequate fetal growth. The aim of the present study was to elucidate the effects of PUFAs on the expression and function of placental transporters, which play important roles in placental functions including the supply of nutrients to the fetus, excretion of metabolites, and protection of the fetus from xenobiotics. METHODS Human placental choriocarcinoma BeWo cells were used as a trophoblast model. PUFA-induced alteration in the gene expression of 84 transporters was investigated by a commercially available PCR array. Protein levels and the activity of transporters were assessed by western blotting and uptake experiments, respectively. The placental expression of the transporters was analyzed using pregnant Wistar rats. RESULTS PUFAs (AA, EPA, and DHA) increased cystine/glutamate transporter xCT/SLC7A11, which mediates the cellular uptake of cystine coupled with the efflux of glutamate in human placental choriocarcinoma BeWo cells. These PUFAs also increased [14C]-cystine uptake in BeWo cells. PUFA-induced xCT/SLC7A11 mRNA expression was not blocked by nuclear factor-erythroid 2-related factor-2 (NRF2) knockdown. Reverse transcription (RT)-PCR analysis indicated that xCT/Slc7a11 mRNA was detected in rat placenta and the expression level at gestational day (GD) 12 was higher than that at GD 20. CONCLUSION These results indicate that PUFAs promoted cystine uptake in placental cells by inducing xCT/SLC7A11 expression and NRF2 did not contribute to upregulation of xCT/SLC7A11 by PUFAs. Furthermore, xCT expression in rat placenta may change during pregnancy.
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Affiliation(s)
- Kanako Ono
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan
| | - Ayako Furugen
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan
| | - Yuko Kurosawa
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan
| | - Naoko Jinno
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan
| | - Katsuya Narumi
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan
| | - Masaki Kobayashi
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo, 060-8648, Japan
| | - Ken Iseki
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo, 060-0812, Japan; Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo, 060-8648, Japan.
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15
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Thrimawithana TR, Rupenthal ID, Räsch SS, Lim JC, Morton JD, Bunt CR. Drug delivery to the lens for the management of cataracts. Adv Drug Deliv Rev 2018; 126:185-194. [PMID: 29604375 DOI: 10.1016/j.addr.2018.03.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/02/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022]
Abstract
Cataracts are one of the most prevalent diseases of the lens, affecting its transparency and are the leading cause of reversible blindness in the world. The clarity of the lens is essential for its normal physiological function of refracting light onto the retina. Currently there is no pharmaceutical treatment for prevention or cure of cataracts and surgery to replace the affected lens remains the gold standard in the management of cataracts. Pharmacological treatment for prevention of cataracts is hindered by many physiological barriers that must be overcome by a therapeutic agent to reach the avascular lens. Various therapeutic agents and formulation strategies are currently being investigated to prevent cataract formation as access to surgery is limited. This review provides a summary of recent research in the field of drug delivery to the lens for the management of cataracts including models used to study cataract treatments and discusses the future perspectives in the field.
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Affiliation(s)
- Thilini R Thrimawithana
- Discipline of Pharmacy, School Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083, Australia.
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Simon S Räsch
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Julie C Lim
- Department of Physiology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - James D Morton
- Faculty of Agricultural Sciences, Lincoln University, P O Box 85084, New Zealand
| | - Craig R Bunt
- Faculty of Agricultural Sciences, Lincoln University, P O Box 85084, New Zealand
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16
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Lim JC, Perwick RD, Li B, Donaldson PJ. Comparison of the expression and spatial localization of glucose transporters in the rat, bovine and human lens. Exp Eye Res 2017. [PMID: 28625822 DOI: 10.1016/j.exer.2017.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The energy required to drive lens transparency is derived from the metabolism of glucose. In the lens, the uptake of glucose is likely to involve either facilitative glucose uptake mediated by members of the GLUT family or Na+ dependent glucose uptake via members of the SGLT family, or both. While GLUT1 and GLUT3 have previously been identified in the rat lens, the expression of SGLTs is unknown. Since antibodies directed against the N and C-terminal epitopes of the GLUT and SGLT family are now commercially available, the purpose of this study is to extend our screening of glucose transporters in the rat lens to include the SGLTs and compare the expression profiles of GLUTs and SGLTs in the different regions of the rat, bovine and human lens. Using a combination of reverse transcriptase PCR, western blotting and immunohistochemistry, we have shown that GLUT1 appears to be the predominant glucose transporter in the rat lens since it was expressed in all regions of the lens. In contrast GLUT3, SGLT1 and SGLT2 had more restricted expression patterns and were only found localised to the inner cortex and core regions of the rat lens. GLUT1 was the only transporter found in the epithelium and appears to exist as a full length form in this region, while in differentiating fiber cells; GLUT1 appears to undergo a modification to its N-terminus. Translating our work to bovine and human lenses revealed that GLUT1 is the only glucose transporter expressed in bovine and human lenses. While GLUT1 in the bovine lens appears to be unmodified throughout the entire lens, GLUT1 in human lenses appears to be N-terminally modified in all regions, including the epithelium. Finally, it appears that GLUT1 expression is maintained in all regions of the human lens with increasing age indicating that there is no further regional or age-dependent processing of GLUT1 in the human lens. Taken together, these studies have identified GLUT1 to be the primary transporter that mediates glucose uptake in the rat, bovine and human lens.
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Affiliation(s)
- Julie C Lim
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand.
| | - Rebecca D Perwick
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Bo Li
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
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17
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Ainsbury EA, Barnard S, Bright S, Dalke C, Jarrin M, Kunze S, Tanner R, Dynlacht JR, Quinlan RA, Graw J, Kadhim M, Hamada N. Ionizing radiation induced cataracts: Recent biological and mechanistic developments and perspectives for future research. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:238-261. [DOI: 10.1016/j.mrrev.2016.07.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 02/06/2023]
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18
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Fan X, Monnier VM, Whitson J. Lens glutathione homeostasis: Discrepancies and gaps in knowledge standing in the way of novel therapeutic approaches. Exp Eye Res 2016; 156:103-111. [PMID: 27373973 DOI: 10.1016/j.exer.2016.06.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 03/10/2016] [Accepted: 06/25/2016] [Indexed: 01/18/2023]
Abstract
Cataract is the major cause of blindness worldwide. The WHO has estimated around 20 million people have bilateral blindness from cataract, and that number is expected to reach 50 million in 2050. The cataract surgery is currently the main treatment approach, though often associated with complications, such as Posterior Capsule Opacification (PCO)-also known as secondary cataract. The lens is an avascular ocular structure equipped with an unusually high level of glutathione (GSH), which plays a vital role in maintaining lens transparency by regulating lenticular redox state. The lens epithelium and outer cortex are thought to be responsible for providing the majority of lens GSH via GSH de novo synthesis, assisted by a continuous supply of constituent amino acids from the aqueous humor, as well as extracellular GSH recycling from the gamma-glutamyl cycle. However, when de novo synthesis is impaired, in the presence of low GSH levels, as in the aging human lens, compensatory mechanisms exist, suggesting that the lens is able to uptake GSH from the surrounding ocular tissues. However, these uptake mechanisms, and the GSH source and its origin, are largely unknown. The lens nucleus does not have the ability to synthesize its own GSH and fully relies on transport from the outer cortex by yet unknown mechanisms. Understanding how aging reduces GSH levels, particularly in the lens nucleus, how it is associated with age-related nuclear cataract (ARNC), and how the lens compensates for GSH loss via external uptake should be a major research priority. The intent of this review, which is dedicated to the memory of David C. Beebe, is to summarize our current understanding of lens GSH homeostasis and highlight discrepancies and gaps in knowledge that stand in the way of pharmacologically minimizing the impact of declining GSH content in the prevention of age-related cataract.
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Affiliation(s)
- Xingjun Fan
- Department of Pathology, Case Western Reserve University, USA.
| | - Vincent M Monnier
- Department of Pathology, Case Western Reserve University, USA; Department of Biochemistry, Case Western Reserve University, USA
| | - Jeremy Whitson
- Department of Pathology, Case Western Reserve University, USA
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19
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Lim JC, Umapathy A, Grey AC, Vaghefi E, Donaldson PJ. Novel roles for the lens in preserving overall ocular health. Exp Eye Res 2016; 156:117-123. [PMID: 27282996 DOI: 10.1016/j.exer.2016.05.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 05/12/2016] [Accepted: 05/29/2016] [Indexed: 12/11/2022]
Abstract
Outside the traditional roles of the lens as an important refractive element and a UV filter, it was David Beebe's group that first demonstrated that the lens acts an oxygen sink that protects the tissues of the anterior segment of the eye from oxygen or oxygen metabolites. In this review, we follow on from this work, and present new evidence from our laboratory to demonstrate that the lens serves as a reservoir for the release of the antioxidant glutathione (GSH) into the aqueous humor to provide a source of GSH and/or its precursor amino acids to nearby tissues that interface with the aqueous humor, or to remove toxic metabolites from the eye via the aqueous outflow pathway. In addition to GSH release, our laboratory and others have shown that ATP is released from the lens under hyposmotic conditions to activate purinergic signalling pathways in an autocrine manner to alter lens function. In this review, we raise the idea that ATP and/or its subsequent degradation product adenosine may exert a paracrine function and influence purinergic signalling systems in other tissues to alter aqueous humor outflow. These new secondary roles indicate that the lens is not just a passive optical element, but a highly dynamic and active tissue that interacts with its neighbouring tissues, through modifying the environments in which these tissues function. We believe that the lens actively contributes to the ocular environment and as a consequence, removal of the lens would alter the functionality of neighbouring tissues. We speculate that a long term effect of lens removal may be to inadvertently increase the exposure of anterior tissues of the eye to oxidative stress due to elevated oxygen levels and a reduction in the availability of GSH and purinergic signalling molecules in the aqueous humor. Since cataract surgery is now being performed on younger patients due to our increasing diabetic population, over time, we predict these changes may increase the susceptibility of these tissues to oxidative stress and the incidence of subsequent ocular pathologies. If our view of the lens is correct, the actual loss of the biological lens may have longer term consequences for overall ocular health than currently appreciated.
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Affiliation(s)
- Julie C Lim
- Department of Physiology, University of Auckland, Auckland, New Zealand; School of Medical Sciences, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand.
| | - Ankita Umapathy
- Department of Physiology, University of Auckland, Auckland, New Zealand; School of Medical Sciences, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Angus C Grey
- Department of Physiology, University of Auckland, Auckland, New Zealand; School of Medical Sciences, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, University of Auckland, Auckland, New Zealand; School of Medical Sciences, University of Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, New Zealand
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20
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Barnes S, Quinlan RA. Small molecules, both dietary and endogenous, influence the onset of lens cataracts. Exp Eye Res 2016; 156:87-94. [PMID: 27039707 DOI: 10.1016/j.exer.2016.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/18/2016] [Accepted: 03/28/2016] [Indexed: 12/11/2022]
Abstract
How the lens ages successfully is a lesson in biological adaption and the emergent properties of its complement of cells and proteins. This living tissue contains some of the oldest proteins in our bodies and yet they remain functional for decades, despite exposure to UV light, to reactive oxygen species and all the other hazards to protein function. This remarkable feat is achieved by a shrewd investment in very stable proteins as lens crystallins, by providing a reservoir of ATP-independent protein chaperones unequalled by any other tissue and by an oxidation-resistant environment. In addition, glutathione, a free radical scavenger, is present in mM concentrations and the plasma membranes contain oxidation-resistant sphingolipids what compromises lens function as it ages? In this review, we examine the role of small molecules in the prevention or causation of cataracts, including those associated with diet, metabolic pathways and drug therapy (steroids).
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Affiliation(s)
- Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Roy A Quinlan
- Biophysical Sciences Institute, University of Durham, Durham DH1 3LE, UK; University of Durham, Durham DH1 3LE, UK.
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21
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Langford-Smith A, Tilakaratna V, Lythgoe PR, Clark SJ, Bishop PN, Day AJ. Age and Smoking Related Changes in Metal Ion Levels in Human Lens: Implications for Cataract Formation. PLoS One 2016; 11:e0147576. [PMID: 26794210 PMCID: PMC4721641 DOI: 10.1371/journal.pone.0147576] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/05/2016] [Indexed: 12/13/2022] Open
Abstract
Age-related cataract formation is the primary cause of blindness worldwide and although treatable by surgical removal of the lens the majority of sufferers have neither the finances nor access to the medical facilities required. Therefore, a better understanding of the pathogenesis of cataract may identify new therapeutic targets to prevent or slow its progression. Cataract incidence is strongly correlated with age and cigarette smoking, factors that are often associated with accumulation of metal ions in other tissues. Therefore this study evaluated the age-related changes in 14 metal ions in 32 post mortem human lenses without known cataract from donors of 11 to 82 years of age by inductively coupled plasma mass spectrometry; smoking-related changes in 10 smokers verses 14 non-smokers were also analysed. A significant age-related increase in selenium and decrease in copper ions was observed for the first time in the lens tissue, where cadmium ion levels were also increased as has been seen previously. Aluminium and vanadium ions were found to be increased in smokers compared to non-smokers (an analysis that has only been carried out before in lenses with cataract). These changes in metal ions, i.e. that occur as a consequence of normal ageing and of smoking, could contribute to cataract formation via induction of oxidative stress pathways, modulation of extracellular matrix structure/function and cellular toxicity. Thus, this study has identified novel changes in metal ions in human lens that could potentially drive the pathology of cataract formation.
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Affiliation(s)
- Alex Langford-Smith
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Viranga Tilakaratna
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Paul R Lythgoe
- School of Earth, Atmospheric and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, University of Manchester, Manchester, United Kingdom
| | - Simon J Clark
- Centre for Ophthalmology and Vision Sciences, Institute of Human Development, University of Manchester, Manchester, United Kingdom.,Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Paul N Bishop
- Centre for Ophthalmology and Vision Sciences, Institute of Human Development, University of Manchester, Manchester, United Kingdom.,Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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22
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Yin J, Ren W, Yang G, Duan J, Huang X, Fang R, Li C, Li T, Yin Y, Hou Y, Kim SW, Wu G. L-Cysteine metabolism and its nutritional implications. Mol Nutr Food Res 2015; 60:134-46. [PMID: 25929483 DOI: 10.1002/mnfr.201500031] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/08/2015] [Accepted: 04/23/2015] [Indexed: 01/17/2023]
Abstract
L-Cysteine is a nutritionally semiessential amino acid and is present mainly in the form of L-cystine in the extracellular space. With the help of a transport system, extracellular L-cystine crosses the plasma membrane and is reduced to L-cysteine within cells by thioredoxin and reduced glutathione (GSH). Intracellular L-cysteine plays an important role in cellular homeostasis as a precursor for protein synthesis, and for production of GSH, hydrogen sulfide (H(2)S), and taurine. L-Cysteine-dependent synthesis of GSH has been investigated in many pathological conditions, while the pathway for L-cysteine metabolism to form H(2)S has received little attention with regard to prevention and treatment of disease in humans. The main objective of this review is to highlight the metabolic pathways of L-cysteine catabolism to GSH, H(2)S, and taurine, with special emphasis on therapeutic and nutritional use of L-cysteine to improve the health and well-being of animals and humans.
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Affiliation(s)
- Jie Yin
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenkai Ren
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Guan Yang
- Department of Animal Science, University of Florida, Gainesville, FL, USA
| | - Jielin Duan
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xingguo Huang
- Department of Animal Science, Hunan Agriculture University, Changsha, China
| | - Rejun Fang
- Department of Animal Science, Hunan Agriculture University, Changsha, China
| | - Chongyong Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Tiejun Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Yulong Yin
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- School of Life Sciences, Hunan Normal University, Changsha, China
| | - Yongqing Hou
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Wuhan Polytechnic University, Wuhan, China
| | - Sung Woo Kim
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | - Guoyao Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Wuhan Polytechnic University, Wuhan, China
- Department of Animal Science, Texas A&M University, College Station, TX, USA
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Langford MP, Redens TB, Liang C, Kavanaugh AS, Texada DE. EAAT and Xc⁻ Exchanger Inhibition Depletes Glutathione in the Transformed Human Lens Epithelial Cell Line SRA 01/04. Curr Eye Res 2015; 41:357-66. [PMID: 25897760 DOI: 10.3109/02713683.2015.1017651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
PURPOSE Maintaining the high glutathione (GSH; tripeptide of glutamate, cysteine and glycine) levels in the lens cortex promotes lens health. The role of glutamate/aspartate (Glu/Asp) transporters and the cystine (Cys)/Glu exchanger (Xc(-) exchanger) in maintaining GSH in transformed human lens epithelial cells (SRA 01/04) was investigated. METHODS Detection and differentiation of excitatory amino acid transporters (EAAT1-5) and the Xc(-) exchanger was performed by the uptake of radiolabeled l-Glu, d-Asp and l-Cys in the presence and absence of Na(+), substrate-specific inhibition studies and Western-blot analysis. Reductions in GSH levels post-inhibition of Xc(-) exchanger and EAAT activities by substrate inhibitors demonstrated the roles of EAAT and Xc(-) exchanger in maintaining GSH. RESULTS Glu and d-Asp uptake in HLEC was Na(+)-dependent. Strong inhibition by substrate-specific Glu/Asp uptake inhibitors and weak inhibition by kainic acid (KA) was consistent with Na(+)-dependent EAAT1/3/4/5 activity and weak EAAT2 activity, respectively. Na(+)-independency and Glu inhibition of Cys uptake were consistent with Xc(-) exchanger activity, but inhibition of Na(+)-dependent Cys uptake by N-acetylcysteine suggests Cys uptake by EAAT3. EAAT1-5 and xCT (Xc(-) exchanger light chain) immunoreactive peptides were detected by Western-blot analysis of HLEC lysates. EAAT and Xc(-) exchanger inhibition by substrate antagonists depleted GSH concentrations by 15-28% (p's ≤ 0.02), while GSH synthesis inhibition by buthionine sulfoximine depleted GSH by 33% (p = 0.008). CONCLUSION Inhibition of Glu and Cys uptake by EAAT and Xc(-) exchanger antagonists depletes GSH in human lens epithelial cells. These in vitro results support pivotal roles for EAAT and Xc(-) exchanger activities in maintaining GSH and protection against oxidative stress in cortical lens epithelium.
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Affiliation(s)
- Marlyn P Langford
- a Department of Ophthalmology , Louisiana State University Health Sciences Center , Shreveport , LA , USA
| | - Thomas B Redens
- a Department of Ophthalmology , Louisiana State University Health Sciences Center , Shreveport , LA , USA
| | - Chanping Liang
- a Department of Ophthalmology , Louisiana State University Health Sciences Center , Shreveport , LA , USA
| | - A Scott Kavanaugh
- a Department of Ophthalmology , Louisiana State University Health Sciences Center , Shreveport , LA , USA
| | - Donald E Texada
- a Department of Ophthalmology , Louisiana State University Health Sciences Center , Shreveport , LA , USA
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Langford MP, Redens TB, Texada DE. Excitatory Amino Acid Transporters, Xc− Antiporter, γ-Glutamyl Transpeptidase, Glutamine Synthetase, and Glutathione in Human Corneal Epithelial Cells. OXIDATIVE STRESS IN APPLIED BASIC RESEARCH AND CLINICAL PRACTICE 2015. [DOI: 10.1007/978-1-4939-1935-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Vorontsova I, Lam L, Delpire E, Lim J, Donaldson P. Identification of the WNK-SPAK/OSR1 signaling pathway in rodent and human lenses. Invest Ophthalmol Vis Sci 2014; 56:310-21. [PMID: 25515571 DOI: 10.1167/iovs.14-15911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify whether the kinases that regulate the activity of cation chloride cotransporters (CCC) in other tissues are also expressed in rat and human lenses. METHODS The expression of with-no-lysine kinase (WNK 1, 3, 4), oxidative stress response kinase 1 (OSR1), and Ste20-like proline alanine rich kinase (SPAK) were determined at either the transcript or protein levels in the rat and human lenses by reverse-transcriptase PCR and/or Western blotting, respectively. Selected kinases were regionally and subcellularly characterized in rat and human lenses. The transparency, wet weight, and tissue morphology of lenses extracted from SPAK knock-out animals was compared with wild-type lenses. RESULTS WNK 1, 3, 4, SPAK, and OSR1 were identified at the transcript level in rat lenses and WNK1, 4, SPAK, and OSR1 expression confirmed at the protein level in both rat and human lenses. SPAK and OSR1 were found to associate with membranes as peripheral proteins and exhibited distinct subcellular and region-specific expression profiles throughout the lens. No significant difference in the wet weight of SPAK knock-out lenses was detected relative to wild-type lenses. However, SPAK knock-out lenses showed an increased susceptibility to opacification. CONCLUSIONS Our results show that the WNK 1, 3, 4, OSR1, and SPAK signaling system known to play a role in regulating the phosphorylation status, and hence activity of the CCCs in other tissues, is also present in the rat and human lenses. The increased susceptibility of SPAK lenses to opacification suggests that disruption of this signaling pathway may compromise the ability of the lens to control its volume, and its ability to maintain its transparency.
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Affiliation(s)
- Irene Vorontsova
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Leo Lam
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Julie Lim
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul Donaldson
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand School of Medical Sciences, University of Auckland, New Zealand
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