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Mrugacz M, Pony-Uram M, Bryl A, Zorena K. Current Approach to the Pathogenesis of Diabetic Cataracts. Int J Mol Sci 2023; 24:ijms24076317. [PMID: 37047290 PMCID: PMC10094546 DOI: 10.3390/ijms24076317] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/13/2023] [Accepted: 03/25/2023] [Indexed: 03/30/2023] Open
Abstract
Cataracts remain the first or second leading cause of blindness in all world regions. In the diabetic population, cataracts not only have a 3–5 times higher incidence than in the healthy population but also affect people at a younger age. In patients with type 1 diabetes, cataracts occur on average 20 years earlier than in the non-diabetic population. In addition, the risk of developing cataracts increases with the duration of diabetes and poor metabolic control. A better understanding of the mechanisms leading to the formation of diabetic cataracts enables more effective treatment and a holistic approach to the patient.
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Heruye SH, Maffofou Nkenyi LN, Singh NU, Yalzadeh D, Ngele KK, Njie-Mbye YF, Ohia SE, Opere CA. Current Trends in the Pharmacotherapy of Cataracts. Pharmaceuticals (Basel) 2020; 13:E15. [PMID: 31963166 PMCID: PMC7168925 DOI: 10.3390/ph13010015] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/23/2022] Open
Abstract
Cataracts, one of the leading causes of preventable blindness worldwide, refers to lens degradation that is characterized by clouding, with consequent blurry vision. As life expectancies improve, the number of people affected with cataracts is predicted to increase worldwide, especially in low-income nations with limited access to surgery. Although cataract surgery is considered safe, it is associated with some complications such as retinal detachment, warranting a search for cheap, pharmacological alternatives to the management of this ocular disease. The lens is richly endowed with a complex system of non-enzymatic and enzymatic antioxidants which scavenge reactive oxygen species to preserve lens proteins. Depletion and/or failure in this primary antioxidant defense system contributes to the damage observed in lenticular molecules and their repair mechanisms, ultimately causing cataracts. Several attempts have been made to counteract experimentally induced cataract using in vitro, ex vivo, and in vivo techniques. The majority of the anti-cataract compounds tested, including plant extracts and naturally-occurring compounds, lies in their antioxidant and/or free radical scavenging and/or anti-inflammatory propensity. In addition to providing an overview of the pathophysiology of cataracts, this review focuses on the role of various categories of natural and synthetic compounds on experimentally-induced cataracts.
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Affiliation(s)
- Segewkal H. Heruye
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Leonce N. Maffofou Nkenyi
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Neetu U. Singh
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | | | - Kalu K. Ngele
- Department of Biology/Microbiology/Biotechnology, Federal University Ndufu Alike Ikwo, Abakaliki, Nigeria
| | - Ya-Fatou Njie-Mbye
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA
| | - Sunny E. Ohia
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA
| | - Catherine A. Opere
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
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SOD1 deficiency alters gastrointestinal microbiota and metabolites in mice. Exp Gerontol 2019; 130:110795. [PMID: 31805337 DOI: 10.1016/j.exger.2019.110795] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 11/25/2019] [Accepted: 11/25/2019] [Indexed: 02/06/2023]
Abstract
Redox imbalance induces oxidative damage and causes age-related pathologies. Mice lacking the antioxidant enzyme SOD1 (Sod1-/-) exhibit various aging-like phenotypes throughout the body and are used as aging model mice. Recent reports suggested that age-related changes in the intestinal environment are involved in various diseases. We investigated cecal microbiota profiles and gastrointestinal metabolites in wild-type (Sod1+/+) and Sod1-/- mice. Firmicutes and Bacteroidetes were dominant in Sod1+/+ mice, and most of the detected bacterial species belong to these two phyla. Meanwhile, the Sod1-/- mice had an altered Firmicutes and Bacteroidetes ratio compared to Sod1+/+ mice. Among the identified genera, Paraprevotella, Prevotella, Ruminococcus, and Bacteroides were significantly increased, but Lactobacillus was significantly decreased in Sod1-/- mice compared to Sod1+/+ mice. The correlation analyses between cecal microbiota and liver metabolites showed that Bacteroides and Prevotella spp. were grouped into the same cluster, and Paraprevotella and Ruminococcus spp. were also grouped as another cluster. These four genera showed a positive and a negative correlation with increased and decreased liver metabolites in Sod1-/- mice, respectively. In contrast, Lactobacillus spp. showed a negative correlation with increased liver metabolites and a positive correlation with decreased liver metabolites in Sod1-/- mice. These results suggest that the redox imbalance induced by Sod1 loss alters gastrointestinal microflora and metabolites.
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Kelkar A, Kelkar J, Mehta H, Amoaku W. Cataract surgery in diabetes mellitus: A systematic review. Indian J Ophthalmol 2018; 66:1401-1410. [PMID: 30249823 PMCID: PMC6173035 DOI: 10.4103/ijo.ijo_1158_17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 05/01/2018] [Indexed: 12/20/2022] Open
Abstract
India is considered the diabetes capital of the world, and a significant proportion of patients undergoing cataract surgery are diabetic. Considering this, we reviewed the principles and guidelines of managing cataract in patients with diabetes. The preoperative, intraoperative, and postoperative factors are of paramount importance in the management of diabetic cataract patients. Particularly, the early recognition and treatment of diabetic retinopathy or maculopathy before cataract surgery influence the final visual outcome and play a major role in perioperative decision-making. Better understanding of various factors responsible for favorable outcome of cataract surgery in diabetic patients may guide us in better overalll management of these patients and optimizing the results.
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Affiliation(s)
- Aditya Kelkar
- National Institute of Ophthalmology, Pune, Maharashtra, India
| | - Jai Kelkar
- National Institute of Ophthalmology, Pune, Maharashtra, India
| | - Hetal Mehta
- National Institute of Ophthalmology, Pune, Maharashtra, India
| | - Winfried Amoaku
- Department of Ophthalmology, Nottingham University Hospitals NHS Trust, University of Nottingham, Nott Inghamshire, UK
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Kaliszewski M, Kennedy AK, Blaes SL, Shaffer RS, Knott AB, Song W, Hauser HA, Bossy B, Huang TT, Bossy-Wetzel E. SOD1 Lysine 123 Acetylation in the Adult Central Nervous System. Front Cell Neurosci 2016; 10:287. [PMID: 28066183 PMCID: PMC5167747 DOI: 10.3389/fncel.2016.00287] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 12/01/2016] [Indexed: 01/09/2023] Open
Abstract
Superoxide dismutase 1 (SOD1) knockout (Sod1−/−) mice exhibit an accelerated aging phenotype. In humans, SOD1 mutations are linked to familial amyotrophic lateral sclerosis (ALS), and post-translational modification (PTM) of wild-type SOD1 has been associated with sporadic ALS. Reversible acetylation regulates many enzymes and proteomic studies have identified SOD1 acetylation at lysine 123 (K123). The function and distribution of K123-acetylated SOD1 (Ac-K123 SOD1) in the nervous system is unknown. Here, we generated polyclonal rabbit antibodies against Ac-K123 SOD1. Sod1 deletion in Sod1−/− mice, K123 mutation or preabsorption with Ac-K123 peptide all abolished antibody binding. Using immunohistochemistry, we assessed Ac-K123 SOD1 distribution in the normal adult mouse nervous system. In the cerebellum, Ac-K123 SOD1 staining was prominent in cell bodies of the granular cell layer (GCL) and Purkinje cell dendrites and interneurons of the molecular cell layer. In the hippocampus, Ac-K123 SOD1 staining was strong in the fimbria, subiculum, pyramidal cells and Schaffer collateral fibers of the cornus ammonis field 1 (CA1) region and granule and neuronal progenitor cells of the dentate gyrus. In addition, labeling was observed in the choroid plexus (CP) and the ependyma of the brain ventricles and central canal of the spinal cord. In the olfactory bulb, Ac-K123 SOD1 staining was prominent in axons of sensory neurons, in cell bodies of interneurons and neurites of the mitral and tufted cells. In the retina, labeling was strong in the retinal ganglion cell layer (RGCL) and axons of retinal ganglion cells (RGCs), the inner nuclear layer (INL) and cone photoreceptors of the outer nuclear layer (ONL). In summary, our findings describe Ac-K123 SOD1 distribution to distinct regions and cell types of the normal nervous system.
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Affiliation(s)
- Michael Kaliszewski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Austin K Kennedy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Shelby L Blaes
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Robert S Shaffer
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Andrew B Knott
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Wenjun Song
- Burnett School of Biomedical Sciences, College of Medicine, University of Central FloridaOrlando, FL, USA; Yale School of Forestry and Environmental Studies, Yale UniversityNew Haven, CT, USA
| | - Henry A Hauser
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Blaise Bossy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
| | - Ting-Ting Huang
- Department of Neurology and Neurological Sciences, Stanford University School of MedicineStanford, CA, USA; Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care SystemPalo Alto, CA, USA
| | - Ella Bossy-Wetzel
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
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Effects of histone acetylation on superoxide dismutase 1 gene expression in the pathogenesis of senile cataract. Sci Rep 2016; 6:34704. [PMID: 27703255 PMCID: PMC5050424 DOI: 10.1038/srep34704] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 09/15/2016] [Indexed: 12/01/2022] Open
Abstract
Histone acetylation plays key roles in gene expression, but its effects on superoxide dismutase 1 (SOD1) expression in senile cataract remains unknown. To address this problem, the study was to investigate the influence of histone acetylation on SOD1 expression and its effects in the pathogenesis of senile cataract. Senile cataract was classified into three types—nuclear cataract (NC), cortical cataract (CC), and posterior subcapsular cataract (SC)—using the Lens Opacities Classification System III. In senile cataracts, SOD1 expression decreased significantly. Both H3 and H4 were deacetylated at −600 bp of the SOD1 promoter of cataract lenses, and hypoacetylated at −1500, −1200, and −900 bp. In hypoacetylated histones, the hypoacetylation pattern differed among the cataracts. In vitro, anacardic acid (AA) significantly reduced H3 and H4 acetylation at the SOD1 promoter, decreased protein expression, and induced cataract formation in rabbits. AA also inhibited HLEC viability and increased cell apoptosis. In contrast, trichostatin A (TSA) was able to efficaciously stop AA’s effects on both rabbit lenses and HLECs. Decreased histone acetylation at the SOD1 promoter is associated with declined SOD1 expression in senile cataracts. Histone acetylation plays an essential role in the regulation of SOD1 expression and in the pathogenesis of senile cataracts.
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Adhikari M, Arora R. The flavonolignan-silymarin protects enzymatic, hematological, and immune system against γ-radiation-induced toxicity. ENVIRONMENTAL TOXICOLOGY 2016; 31:641-654. [PMID: 25411116 DOI: 10.1002/tox.22076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 10/24/2014] [Accepted: 10/31/2014] [Indexed: 06/04/2023]
Abstract
The main focus of this study is evaluation of radioprotective efficacy of silymarin, a flavonolignan, against γ-radiation-induced damage to hematological, vital organs (liver and intestine), and immune system. Survival studies revealed that silymarin (administered orally for 3 days) provided maximum protection (67%) at 70 mg/kg body weight (b.wt.) against lethal 9 Gy γ-irradiation (dose reduction factor = 1.27). The study revealed significant (p < 0.05) changes in levels of catalase (12.57 ± 2.58 to 30.24 ± 4.89 units), glutathione peroxidase (6.23 ± 2.95 to 13.26 ± 1.36 µg of reduced glutathione consumed/min/mg protein), glutathione reductase (0.25 ± 5.6 to 11.65 ± 2.83 pM NADPH consumed/min/mg protein), and superoxide dismutase (11.74 ± 0.2 to 16.09 ± 3.47 SOD U/mg of protein) activity at 30th day. Silymarin pretreated irradiated group exhibited increased proliferation in erythrocyte count (1.76 ± 0.41 × 10(6) to 9.25 ± 0.24 × 10(6) ), hemoglobin (2.15 ± 0.48g/dL to 14.77 ± 0.25g/dL), hematocrit (4.55 ± 0.24% to 37.22 ± 0.21%), and total leucocyte count (1.4 ± 0.15 × 10(6) to 8.31 ± 0.47 × 10(6) ) as compared with radiation control group on 15th day. An increase in CD4:CD8 ratio was witnessed (0.2-1%) at 30th day time interval using flow cytometry. Silymarin also countered radiation-induced decrease (p < 0.05) in regulatory T-cells (Tregs ) (11.23% in radiation group at 7th day versus 0.1% in pretreated silymarin irradiated group at 15th day). The results of this study indicate that flavonolignan-silymarin protects enzymatic, hematological, and immune system against γ-radiation-induced toxicity and might prove useful in management of nuclear and radiological emergencies. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 641-654, 2016.
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Affiliation(s)
- Manish Adhikari
- Radiation Biotechnology Group, Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Brig SK Mazumdar Marg, Delhi, 110054, India
| | - Rajesh Arora
- Radiation Biotechnology Group, Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Brig SK Mazumdar Marg, Delhi, 110054, India
- Office of the Distinguished Scientist and Director General-Life Sciences, DRDO Head Quarters, DRDO Bhawan, Rajaji Marg, New Delhi, 110011, India
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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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Watanabe K, Shibuya S, Ozawa Y, Nojiri H, Izuo N, Yokote K, Shimizu T. Superoxide dismutase 1 loss disturbs intracellular redox signaling, resulting in global age-related pathological changes. BIOMED RESEARCH INTERNATIONAL 2014; 2014:140165. [PMID: 25276767 PMCID: PMC4170698 DOI: 10.1155/2014/140165] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/29/2014] [Accepted: 08/06/2014] [Indexed: 01/14/2023]
Abstract
Aging is characterized by increased oxidative stress, chronic inflammation, and organ dysfunction, which occur in a progressive and irreversible manner. Superoxide dismutase (SOD) serves as a major antioxidant and neutralizes superoxide radicals throughout the body. In vivo studies have demonstrated that copper/zinc superoxide dismutase-deficient (Sod1(-/-)) mice show various aging-like pathologies, accompanied by augmentation of oxidative damage in organs. We found that antioxidant treatment significantly attenuated the age-related tissue changes and oxidative damage-associated p53 upregulation in Sod1(-/-) mice. This review will focus on various age-related pathologies caused by the loss of Sod1 and will discuss the molecular mechanisms underlying the pathogenesis in Sod1(-/-) mice.
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Affiliation(s)
- Kenji Watanabe
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Shuichi Shibuya
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Yusuke Ozawa
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Hidetoshi Nojiri
- Department of Orthopaedics, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naotaka Izuo
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Koutaro Yokote
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
| | - Takahiko Shimizu
- Department of Advanced Aging Medicine, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
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Taysi S, Okumus S, Akyuz M, Uzun N, Aksoy A, Demir E, Orkmez M, Tarakcioglu M, Adli M. Zinc administration modulates radiation-induced oxidative injury in lens of rat. Pharmacogn Mag 2013; 8:245-9. [PMID: 24082625 PMCID: PMC3785159 DOI: 10.4103/0973-1296.103646] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/24/2012] [Accepted: 11/22/2012] [Indexed: 11/22/2022] Open
Abstract
Background: The aim of this study was to evaluate the antioxidant role of zinc (Zn) against radiation-induced cataract in the rat lens after total cranial irradiation with a single 5 Gray (Gy) dose of gamma irradiation. Materials and Methods: Twenty-one Sprague-Dawley rats were used for the experiment. The control group did not receive Zn or irradiation but received 1-ml saline orally plus sham-irradiation. The irradiation (IR) group received 5 Gy gamma irradiation to the total cranium as a single dose plus 0.1 ml physiological saline intraperitoneally. The IR plus Zn group received irradiation to total cranium plus 10 mg/kg/day Zn intraperitoneally. Biochemical parameters measured in rat lenses were carried out using spectrophotometric techniques. Results: Lens total (enzymatic plus non-enzymatic) superoxide scavenger activity (TSSA), glutathione reductase (GRD), and glutathione-S-transferase (GST) activities significantly increased in the IR plus Zn groups when compared with the IR group. However, TSSA, GRD and GST activities were significantly lower in the IR group when compared with the control group. Lens non-enzymatic superoxide scavenger activity (NSSA) in the IR plus Zn group was significantly increased compared to that of the IR group. Lens xanthine oxidase (XO) activity in the IR group significantly increased compared to that of both the control and IR plus Zn groups. Conclusion: Zn has clear antioxidant properties and prevented oxidative stress by scavenging free radicals generated by ionizing radiation in rat lenses.
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Affiliation(s)
- Seyithan Taysi
- Department of Medical Biochemistry, Gaziantep University, Medical School, Gaziantep, Turkey
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Olofsson EM, Marklund SL, Behndig A. Enhanced age-related cataract in copper-zinc superoxide dismutase null mice. Clin Exp Ophthalmol 2012; 40:813-20. [DOI: 10.1111/j.1442-9071.2012.02794.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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12
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Role of ultraviolet irradiation and oxidative stress in cataract formation-medical prevention by nutritional antioxidants and metabolic agonists. Eye Contact Lens 2011; 37:233-45. [PMID: 21670697 DOI: 10.1097/icl.0b013e31821ec4f2] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Cataract is a significant cause of visual disability with relatively high incidence. It has been proposed that such high incidence is related to oxidative stress induced by continued intraocular penetration of light and consequent photochemical generation of reactive oxygen species, such as superoxide and singlet oxygen and their derivatization to other oxidants, such as hydrogen peroxide and hydroxyl radical. The latter two can also interact to generate singlet oxygen by Haber-Weiss reaction. It has been proposed that in addition to the endogenous enzymatic antioxidant enzymes, the process can be inhibited by many nutritional and metabolic oxyradical scavengers, such as ascorbate, vitamin E, pyruvate, and xanthine alkaloids, such as caffeine. METHODS Initial verification of the hypothesis has been done primarily by rat and mouse lens organ culture studies under ambient as well as ultraviolet (UV) light irradiation and determining the effect of such irradiation on its physiology in terms of its efficiency of active membrane transport activity and the levels of certain metabolites such as glutathione and adenosine triphosphate as well as in terms of apoptotic cell death. In vivo studies on the possible prevention of oxidative stress and cataract formation have been conducted by administering pyruvate and caffeine orally in drinking water and by their topical application using diabetic and galactosemic animal models. RESULTS Photosensitized damage to lens caused by exposure to visible light and UVA has been found to be significantly prevented by ascorbate and pyruvate. Caffeine has been found be effective against UVA and UVB. Oral or topical application of pyruvate has been found to inhibit the formation of cataracts induced by diabetes and galactosemia. Caffeine has also been found to inhibit cataract induced by sodium selenite and high levels of galactose. Studies with diabetes are in progress. CONCLUSIONS Various in vitro and in vivo studies summarized in this review strongly support the hypothesis that light penetration into the eye is a significant contributory factor in the genesis of cataracts. The major effect is through photochemical generation of reactive oxygen species and consequent oxidative stress to the tissue. The results demonstrate that this can be averted by the use of various antioxidants administered preferably by topical route. That they will be so effective is strongly suggested by the effectiveness of pyruvate and caffeine administered topically to diabetic and galactosemic animals.
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Nojiri H, Saita Y, Morikawa D, Kobayashi K, Tsuda C, Miyazaki T, Saito M, Marumo K, Yonezawa I, Kaneko K, Shirasawa T, Shimizu T. Cytoplasmic superoxide causes bone fragility owing to low-turnover osteoporosis and impaired collagen cross-linking. J Bone Miner Res 2011; 26:2682-94. [PMID: 22025246 DOI: 10.1002/jbmr.489] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The aging process correlates with the accumulation of cellular and tissue damage caused by oxidative stress. Although previous studies have suggested that oxidative stress plays a pathologic role in the development of bone fragility, little direct evidence has been found. In order to investigate the pathologic significance of oxidative stress in bones, we analyzed the bone tissue of mice deficient in cytoplasmic copper/zinc superoxide dismutase (CuZn-SOD, encoded by the Sod1 gene; Sod1(-/-)). In this study, we showed for the first time that in vivo cytoplasmic superoxide caused a distinct weakness in bone stiffness and decreased BMD, aging-like changes in collagen cross-linking, and transcriptional alterations in the genes associated with osteogenesis. We also showed that the surface areas of osteoblasts and osteoclasts were decreased significantly in the lumbar vertebrae of Sod1(-/-) mice, indicating the occurrence of low-turnover osteopenia. In vitro experiments demonstrated that intracellular oxidative stress induced cell death and reduced the proliferation in primary osteoblasts but not in osteoclasts, indicating that impaired osteoblast viability caused the decrease in osteoblast number and suppressed RANKL/M-CSF osteoclastogenic signaling in bone. Furthermore, treatment with an antioxidant, vitamin C, effectively improved bone fragility and osteoblastic survival. These results imply that intracellular redox imbalance caused by SOD1 deficiency plays a pivotal role in the development and progression of bone fragility both in vivo and in vitro. We herein present a valuable model for investigating the effects of oxidative stress on bone fragility in order to develop suitable therapeutic interventions.
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Affiliation(s)
- Hidetoshi Nojiri
- Molecular Gerontology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan
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Okumus S, Taysi S, Orkmez M, Saricicek E, Demir E, Adli M, Al B. The effects of oral Ginkgo biloba supplementation on radiation-induced oxidative injury in the lens of rat. Pharmacogn Mag 2011; 7:141-5. [PMID: 21716624 PMCID: PMC3113353 DOI: 10.4103/0973-1296.80673] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/08/2010] [Accepted: 05/09/2011] [Indexed: 11/08/2022] Open
Abstract
Background: The aim of this study was to evaluate the antioxidant role of Ginkgo biloba (GB) against radiation-induced cataract in the rat lens after total cranial irradiation with a single 5 Gray (Gy) dose of gamma irradiation. Materials and Methods: Twenty-four Sprague-Dawley rats were used for the experiment. The rats were randomly divided into three equal groups. Group 1 did not receive GB or irradiation (control group) but received 1-ml saline orally plus sham-irradiation. Group 2 received total cranium 5 Gy of gamma irradiation as a single dose (IR group) plus 1-ml saline orally. Group 3 received total cranium irradiation plus 40 mg/kg/day GBE (IR plus GBE group). Biochemical parameters measured in murine lenses were carried out using spectrophotometric techniques. Results: Lens total (enzymatic plus non-enzymatic) superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), glutathione reductase (GRD), and glutathione-S- transferase (GST) activities significantly increased in the IR plus GBE groups when compared with the IR group. However, TSSA, GRD and GST activities were significantly lower in the IR group when compared with the control group. Lens xanthine oxidase (XO) activity in the IR group significantly increased compared to that of both the control and IR plus GBE groups. Conclusion: GBE has clear antioxidant properties and is likely to be a valuable drug for protection against gamma-irradiation and/or be used as an antioxidant against oxidative stress.
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Affiliation(s)
- Seydi Okumus
- Department of Ophthalmology, Gaziantep University, Medical School, Gaziantep, Turkey
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15
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Varma SD, Kovtun S, Hegde KR. UV-Induced Apoptosis in Lens: Prevention by Caffeine. JOURNAL OF CAFFEINE RESEARCH 2011. [DOI: 10.1089/jcr.2011.0016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shambhu D. Varma
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Svitlana Kovtun
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kavita R. Hegde
- Department of Natural Sciences, Coppin State University, Baltimore, Maryland
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16
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Diabetic cataract-pathogenesis, epidemiology and treatment. J Ophthalmol 2010; 2010:608751. [PMID: 20634936 PMCID: PMC2903955 DOI: 10.1155/2010/608751] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 04/02/2010] [Indexed: 12/15/2022] Open
Abstract
Cataract in diabetic patients is a major cause of blindness in developed and developing countries. The pathogenesis of diabetic cataract development is still not fully understood. Recent basic research studies have emphasized the role of the polyol pathway in the initiation of the disease process.
Population-based studies have greatly increased our knowledge concerning the association between diabetes and cataract formation and have defined risk factors for the development of cataract. Diabetic patients also have a higher risk of complications after phacoemulsification cataract surgery compared to nondiabetics. Aldose-reductase inhibitors and antioxidants have been proven beneficial in the prevention or treatment of this sightthreatening condition in in vitro and in vivo experimental studies.
This paper provides an overview of the pathogenesis of diabetic cataract, clinical studies investigating the association between diabetes and cataract development, and current treatment of cataract in diabetics.
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17
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Abstract
PURPOSE The primary objective of this study was to examine the possibility of inhibiting oxidative damage to the lens in vitro by caffeine. METHODS Oxidative damage was inflicted by incubating mouse lenses in Tyrode medium containing 0.1 mM Fe(8)Br(8), an iron complex soluble in aqueous medium. Parallel incubations were conducted in the presence of caffeine (5 mM). RESULTS Lenses incubated in the medium containing Fe(8)Br(8) undergo oxidative stress, as evidenced by the inhibition of Na(+)-K(+) ATPase-driven rubidium transport and the loss of tissue glutathione and ATP. These effects were prevented in presence of caffeine. That the effects are due to the oxyradicals produced was ascertained further by parallel studies with Tempol (5 mM), a well-known scavenger of reactive oxygen species (ROS) with its activity being more pronounced with hydroxyl radicals as compared to other ROS. CONCLUSIONS Caffeine was found to be effective in preventing oxidative stress to the lens induced by iron under ambient conditions. The protective effect is attributable to its ability to scavenge ROS, particularly the hydroxyl radical.
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Affiliation(s)
- Shambhu D Varma
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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18
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Berthoud VM, Beyer EC. Oxidative stress, lens gap junctions, and cataracts. Antioxid Redox Signal 2009; 11:339-53. [PMID: 18831679 PMCID: PMC2763361 DOI: 10.1089/ars.2008.2119] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/12/2008] [Accepted: 07/12/2008] [Indexed: 12/20/2022]
Abstract
The eye lens is constantly subjected to oxidative stress from radiation and other sources. The lens has several mechanisms to protect its components from oxidative stress and to maintain its redox state, including enzymatic pathways and high concentrations of ascorbate and reduced glutathione. With aging, accumulation of oxidized lens components and decreased efficiency of repair mechanisms can contribute to the development of lens opacities or cataracts. Maintenance of transparency and homeostasis of the avascular lens depend on an extensive network of gap junctions. Communication through gap junction channels allows intercellular passage of molecules (up to 1 kDa) including antioxidants. Lens gap junctions and their constituent proteins, connexins (Cx43, Cx46, and Cx50), are also subject to the effects of oxidative stress. These observations suggest that oxidative stress-induced damage to connexins (and consequent altered intercellular communication) may contribute to cataract formation.
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Affiliation(s)
- Viviana M Berthoud
- Department of Pediatrics, University of Chicago, Chicago, Illinois 60637, USA.
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19
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Akoyev V, Das S, Jena S, Grauer L, Takemoto DJ. Hypoxia-regulated activity of PKCepsilon in the lens. Invest Ophthalmol Vis Sci 2008; 50:1271-82. [PMID: 18997087 DOI: 10.1167/iovs.08-2599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To show that hypoxia is necessary to prevent opacification of the lens. Protein kinase C (PKC)-epsilon serves a role that is distinct from PKC-gamma when both PKC isoforms are expressed in the lens. PKCepsilon serves a very important role in hypoxic conditions, helping to prevent opacification of the lens. METHODS Digital image analysis, confocal microscopy, dye transfer assay, coimmunoprecipitation, Western blot analysis, and enzyme activity assays were used, respectively, to study opacification of the lens, intercellular communications, cellular localization of connexin-43 (Cx43), and the interactions between PKCepsilon, PKCgamma, and Cx43 in the lens epithelial cells. RESULTS Hypoxic conditions (1%-5% of oxygen) were very important in maintaining clarity of the lenses of wild-type (WT) mice. Normoxic conditions induced opacification of the WT lens. Lenses from the PKCepsilon-knockout mice underwent rapid opacification, even in hypoxic conditions. Hypoxia did not induce apoptosis in the lens epithelial cells, judging by the absence of active caspase-3, and it did not change intercellular communication and did not affect the number and localization of junctional Cx43 plaques in the lens epithelial cell culture. Hypoxia activated PKCepsilon, whereas phorbol ester (TPA), oxidation (H(2)O(2)), and insulin-like growth factor-1 (IGF-1) activated PKCgamma and decreased the activity of PKCepsilon. Hypoxia did not induce the phosphorylation of the Cx43. CONCLUSIONS Hypoxia-induced activation of PKCepsilon is very important in surviving hypoxia and maintaining the clarity of the lens. However, PKCgamma is utilized in the control of Cx43 gap junctions.
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Affiliation(s)
- Vladimir Akoyev
- Department of Biochemistry, Kansas State University, Manhattan, Kansas
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20
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Geng CM, Ding HL. Double-mismatched siRNAs enhance selective gene silencing of a mutant ALS-causing allele. Acta Pharmacol Sin 2008; 29:211-6. [PMID: 18215350 DOI: 10.1111/j.1745-7254.2008.00740.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIM Our previous study demonstrated an siRNA-mediated, allele-specific silencing of mutant genes that cause amyotrophic lateral sclerosis. To improve siRNA design for better therapeutic use of RNA interference, we systematically tested the base-pairing mismatch strategy in the design of asymmetric siRNA. METHODS A naturally symmetric siRNA that targets the human Cu Zn superoxide dismutase G85R mutant allele was modified by placing either 1 or 2 mismatches at the end of the siRNA from position 1 to 4 at each time. The target preference and silencing efficacy of modified siRNA were measured using a modified dual luciferase system. RESULTS The modification of single base-pairing mismatch successfully achieved the conversion of the siRNA that was originally favored to the antisense of the mutant allele to the one that was favored to the sense strand of the gene. Compared to the single-mismatched siRNA, those with double-mismatch at one end demonstrated an increased asymmetry, and thus, an enhanced specificity and efficacy of gene silencing. In addition, the siRNA with double-mismatch at both ends remained in symmetry. CONCLUSION Our results suggest the effectiveness of converting a symmetric siRNA to an asymmetric one by introducing mismatches into its structure, and the superiority of double-mismatched siRNA to single-mismatched siRNA in producing selective gene silencing resulting from the disruption of siRNA symmetry. The double-mismatch strategy is an improvement of the single-mismatch method and could be useful in the design of effective siRNAs for the treatment of diseases caused by dominant, gain-of-function gene mutations, such as ALS.
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Affiliation(s)
- Chang-ming Geng
- Department of Neurology, Shanghai PLA 85 Hospital, Shanghai 200052, China
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21
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Lin D, Barnett M, Lobell S, Madgwick D, Shanks D, Willard L, Zampighi GA, Takemoto DJ. PKCgamma knockout mouse lenses are more susceptible to oxidative stress damage. ACTA ACUST UNITED AC 2007; 209:4371-8. [PMID: 17050852 DOI: 10.1242/jeb.02524] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cataracts, or lens opacities, are the leading cause of blindness worldwide. Cataracts increase with age and environmental insults, e.g. oxidative stress. Lens homeostasis depends on functional gap junctions. Knockout or missense mutations of lens gap junction proteins, Cx46 or Cx50, result in cataractogenesis in mice. We have previously demonstrated that protein kinase Cgamma (PKCgamma) regulates gap junctions in the lens epithelium and cortex. In the current study, we further determined whether PKCgamma control of gap junctions protects the lens from cataractogenesis induced by oxidative stress in vitro, using PKCgamma knockout and control mice as our models. The results demonstrate that PKCgamma knockout lenses are normal at 2 days post-natal when compared to control. However, cell damage, but not obvious cataract, was observed in the lenses of 6-week-old PKCgamma knockout mice, suggesting that the deletion of PKCgamma causes lenses to be more susceptible to damage. Furthermore, in vitro incubation or lens oxidative stress treatment by H(2)O(2) significantly induced lens opacification (cataract) in the PKCgamma knockout mice when compared to controls. Biochemical and structural results also demonstrated that H(2)O(2) activation of endogenous PKCgamma resulted in phosphorylation of Cx50 and subsequent inhibition of gap junctions in the lenses of control mice, but not in the knockout. Deletion of PKCgamma altered the arrangement of gap junctions on the cortical fiber cell surface, and completely abolished the inhibitory effect of H(2)O(2) on lens gap junctions. Data suggest that activation of PKCgamma is an important mechanism regulating the closure of the communicating pathway mediated by gap junction channels in lens fiber cells. The absence of this regulatory mechanism in the PKCgamma knockout mice may cause those lenses to have increased susceptibility to oxidative damage.
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Affiliation(s)
- Dingbo Lin
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
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22
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Xia X, Zhou H, Huang Y, Xu Z. Allele-specific RNAi selectively silences mutant SOD1 and achieves significant therapeutic benefit in vivo. Neurobiol Dis 2006; 23:578-86. [PMID: 16857362 DOI: 10.1016/j.nbd.2006.04.019] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 04/27/2006] [Accepted: 04/30/2006] [Indexed: 12/13/2022] Open
Abstract
RNA interference (RNAi) has the potential to treat diseases caused by dominant, gain-of-function type of gene mutations. In these diseases, one allele is mutated and produces a toxic protein, whereas the other allele is normal and performs vital functions. One challenge in the treatment is to specifically inhibit the mutant allele toxicity while maintaining the normal allele function. To test allele-specific silencing in vivo, we made transgenic mice that express an shRNA against mutant Cu, Zn superoxide dismutase gene (SOD1(G93A)), which causes amyotrophic lateral sclerosis (ALS) by a gain of an unknown toxic property. By crossing this transgenic line with mice that express SOD1(G93A) and mice that express wild-type human SOD1, we found that this shRNA specifically silences the mutant, but not the wild-type SOD1. The silencing of the mutant significantly delayed ALS onset and extended survival. Thus, RNAi can achieve allele-specific silencing and therapeutic benefit in vivo.
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Affiliation(s)
- Xugang Xia
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St, 817 LRB, Worcester, MA 01605, USA.
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23
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Abstract
Copper (Cu), a redox active metal, is an essential nutrient for all species studied to date. During the past decade, there has been increasing interest in the concept that marginal deficits of this element can contribute to the development and progression of a number of disease states including cardiovascular disease and diabetes. Deficits of this nutrient during pregnancy can result in gross structural malformations in the conceptus, and persistent neurological and immunological abnormalities in the offspring. Excessive amounts of Cu in the body can also pose a risk. Acute Cu toxicity can result in a number of pathologies, and in severe cases, death. Chronic Cu toxicity can result in liver disease and severe neurological defects. The concept that elevated ceruloplasmin is a risk factor for certain diseases is discussed. In this paper, we will review recent literature on the potential causes of Cu deficiency and Cu toxicity, and the pathological consequences associated with the above. Finally, we will review some of the potential biochemical lesions that might underlie these pathologies. Given that oxidative stress is a characteristic of Cu deficiency, the role of Cu in the oxidative defense system will receive special attention. The concept that excess Cu may be a precipitating factor in Alzheimer's disease is discussed.
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Affiliation(s)
- Janet Y Uriu-Adams
- Department of Nutrition, One Shields Ave., University of California-Davis, Davis, CA 95616, USA.
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24
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Wolf N, Penn P, Pendergrass W, Van Remmen H, Bartke A, Rabinovitch P, Martin GM. Age-related cataract progression in five mouse models for anti-oxidant protection or hormonal influence. Exp Eye Res 2005; 81:276-85. [PMID: 16129095 DOI: 10.1016/j.exer.2005.01.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Revised: 01/24/2005] [Accepted: 01/26/2005] [Indexed: 11/23/2022]
Abstract
Five mouse models with known alterations of resistance to oxidative damage were compared by slit lamp examination for the presence and degree of advancement of age-related cataract in young adult and old animals along with wild type controls. A group of young and old normal C57BL/6Jax mice were examined first to constitute a standard, and they were found to exhibit age-related cataract development. Following this, four models on the C57BL/6 background with imposed genetic alterations affecting anti-oxidant enzyme presence or activity, and one outbred model in which a deletion blocked the growth hormone/IGF-1 axis, were similarly examined. There was no evidence of foetal or juvenile cataract development in any of these models, and an age-related severity for lens opacities was shown between young adult and old mice in all groups. Model 1, mice null for the anti-oxidant gene glutathione peroxidase-1 (GPX1) had significantly advanced cataracts in older mice vs. same age controls. In mouse model 2 hemizygous knockout of SOD2 (MnSOD) did not affect age-related cataract development. In model 3 combining the GPX1 and SOD2 deficiencies in the same animal did not advance cataract development beyond that of the GPX1 null alone. In model 4 the addition of anti-oxidant protection in the lens by transfection of human catalase targeted only to the mitochondria resulted in a significant delay in cataract development. The 5th model, growth hormone receptor knockout (GHR-/-) mice, also demonstrated a significant reduction in age-related cataract development, as well as dwarfism. These findings, in general, support the oxidative theory of age-related cataract development. The exception, the partial deletion of SOD2 in the hemizygous KO model, probably did not represent a sufficiently severe deprivation of anti-oxidant protection to produce pathologic changes in the lens.
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Affiliation(s)
- Norman Wolf
- Department of Pathology, University of Washington School of Medicine, Box 3557470, University of Washington, Seattle, WA 98195-7470, USA.
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25
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Olofsson EM, Marklund SL, Karlsson K, Brännström T, Behndig A. In vitro glucose-induced cataract in copper-zinc superoxide dismutase null mice. Exp Eye Res 2005; 81:639-46. [PMID: 15949797 DOI: 10.1016/j.exer.2005.03.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 03/23/2005] [Accepted: 03/31/2005] [Indexed: 02/08/2023]
Abstract
The purpose of this study was to evaluate the involvement of the superoxide radical in glucose-induced cataract using lenses from mice lacking the cytosolic copper-zinc superoxide dismutase (SOD1). Lenses from wild-type mice and SOD1 null mice were kept in organ culture with either 5.6 or 55.6 mM glucose for 6 days. The cataract formation was followed with digital image analysis and ocular staging. The lens damage was further quantified by analysis of the leakage of lactate dehydrogenase into the medium by the uptake of 86Rb and by determining the water content of the lenses. The formation of superoxide radicals in the lenses was assessed with lucigenin-derived chemiluminescence. Immunohistochemical staining for SOD1 was also performed on murine lenses. The SOD1 null lenses exposed to high glucose developed more cataract showed an increased leakage of lactate dehydrogenase and developed more oedema compared to the control lenses. At 5.6 mM glucose there was no difference between the SOD1 null and wild-type lenses. Staining for SOD1 was seen primarily in the cortex of the wild-type lens. This in vitro model suggests an involvement of the superoxide radical and a protective effect of SOD1 in glucose-induced cataract formation.
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Affiliation(s)
- Eva M Olofsson
- Department of Clinical Sciences/Ophthalmology, Umeå University, SE-901 87 Umeå, Sweden.
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26
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Xia XG, Zhou H, Zhou S, Yu Y, Wu R, Xu Z. An RNAi strategy for treatment of amyotrophic lateral sclerosis caused by mutant Cu,Zn superoxide dismutase. J Neurochem 2005; 92:362-7. [PMID: 15663483 DOI: 10.1111/j.1471-4159.2004.02860.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) is a neurodegenerative disease characterized by motor neuron degeneration, paralysis and death. One cause of this disease is mutations in the Cu,Zn superoxide dismutase (SOD1) gene. As mutant SOD1 acquires a toxic property that kills motor neurons, by reducing the mutant protein the disease progression may be slowed or prevented. While mutant SOD1 is toxic, the wild-type SOD1 is indispensable for motor neuron health. Therefore, the ideal therapeutic strategy would be to inhibit selectively the mutant protein expression. Previously we have demonstrated that RNA interference (RNAi) can selectively inhibit some mutant SOD1 expression. However, more than 100 SOD1 mutants can cause ALS and all mutants cannot be inhibited selectively by RNAi. To overcome this obstacle, we have designed a replacement RNAi strategy. Using this strategy, all mutants and wild-type genes are inhibited by RNAi. The wild-type SOD1 function is then replaced by designed wild-type SOD1 genes that are resistant to the RNAi. Here we demonstrate the concept of this strategy.
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Affiliation(s)
- Xu Gang Xia
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts, Worcester, Massachusetts 01605, USA
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27
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Tummala H, Jung C, Tiwari A, Higgins CMJ, Hayward LJ, Xu Z. Inhibition of Chaperone Activity Is a Shared Property of Several Cu,Zn-Superoxide Dismutase Mutants That Cause Amyotrophic Lateral Sclerosis. J Biol Chem 2005; 280:17725-31. [PMID: 15753080 DOI: 10.1074/jbc.m501705200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron degeneration, paralysis, and death. Mutant Cu,Zn-superoxide dismutase (SOD1) causes a subset of ALS by an unidentified toxic property. Increasing evidence suggests that chaperone dysfunction plays a role in motor neuron degeneration in ALS. To investigate the relationship between mutant SOD1 expression and chaperone dysfunction, we measured chaperone function in central nervous system tissue lysates from normal mice and transgenic mice expressing human SOD1 variants. We observed a significant decrease in chaperone activity in tissues from mice expressing ALS-linked mutant SOD1 but not control mice expressing human wild type SOD1. This decrease was detected only in the spinal cord, became apparent by 60 days of age (before the onset of muscle weakness and significant motor neuron loss), and persisted throughout the late stages. In addition, this impairment of chaperone activity occurred only in cytosolic but not in mitochondrial and nuclear fractions. Furthermore, multiple recombinant human SOD1 mutants with differing biochemical and biophysical properties inhibited chaperone function in a cell-free extract of normal mouse spinal cords. Thus, mutant SOD1 proteins may impair chaperone function independent of gene expression in vivo, and this inhibition may be a shared property of ALS-linked mutant SOD1 proteins.
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Affiliation(s)
- Hemachand Tummala
- Department of Biochemistry and Molecular Pharmacology, Neurology, and Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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28
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Kantorow M, Hawse JR, Cowell TL, Benhamed S, Pizarro GO, Reddy VN, Hejtmancik JF. Methionine sulfoxide reductase A is important for lens cell viability and resistance to oxidative stress. Proc Natl Acad Sci U S A 2004; 101:9654-9. [PMID: 15199188 PMCID: PMC470730 DOI: 10.1073/pnas.0403532101] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Age-related cataract, an opacity of the eye lens, is the leading cause of visual impairment in the elderly, the etiology of which is related to oxidative stress damage. Oxidation of methionine to methionine sulfoxide is a major oxidative stress product that reaches levels as high as 60% in cataract while being essentially absent from clear lenses. Methionine oxidation results in loss of protein function that can be reversed through the action of methionine sulfoxide reductase A (MsrA), which is implicated in oxidative stress protection and is an essential regulator of longevity in species ranging from Escherichia coli to mice. To establish a role for MsrA in lens protection against oxidative stress, we have examined the levels and spatial expression patterns of MsrA in the human lens and have tested the ability of MsrA to protect lens cells directly against oxidative stress. In the present report, we establish that MsrA is present throughout the human lens, where it is likely to defend lens cells and their components against methionine oxidation. We demonstrate that overexpression of MsrA protects lens cells against oxidative stress damage, whereas silencing of the MsrA gene renders lens cells more sensitive to oxidative stress damage. We also provide evidence that MsrA is important for lens cell function in the absence of exogenous stress. Collectively, these data implicate MsrA as a key player in lens cell viability and resistance to oxidative stress, a major factor in the etiology of age-related cataract.
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Affiliation(s)
- Marc Kantorow
- Biomedical Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
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29
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Ding H, Schwarz DS, Keene A, Affar EB, Fenton L, Xia X, Shi Y, Zamore PD, Xu Z. Selective silencing by RNAi of a dominant allele that causes amyotrophic lateral sclerosis. Aging Cell 2003; 2:209-17. [PMID: 12934714 DOI: 10.1046/j.1474-9728.2003.00054.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA interference (RNAi) can achieve sequence-selective inactivation of gene expression in a wide variety of eukaryotes by introducing double-stranded RNA corresponding to the target gene. Here we explore the potential of RNAi as a therapy for amyotrophic lateral sclerosis (ALS) caused by mutations in the Cu, Zn superoxide dismutase (SOD1) gene. Although the mutant SOD1 is toxic, the wild-type SOD1 performs important functions. Therefore, the ideal therapeutic strategy should be to selectively inhibit the mutant, but not the wild-type SOD1 expression. Because most SOD1 mutations are single nucleotide changes, to selectively silence the mutant requires single-nucleotide specificity. By coupling rational design of small interfering RNAs (siRNAs) with their validation in RNAi reactions in vitro and in vivo, we have identified siRNA sequences with this specificity. A similarly designed sequence, when expressed as small hairpin RNA (shRNA) under the control of an RNA polymerase III (pol III) promoter, retains the single-nucleotide specificity. Thus, RNAi is a promising therapy for ALS and other disorders caused by dominant, gain-of-function gene mutations.
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Affiliation(s)
- Hongliu Ding
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St, Worcester, MA 01605-2324, USA
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30
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Abstract
The elderly are at nutritional risk as a result of multiple physiological, social, psychological, and economic factors. Elderly persons have a higher incidence of chronic diseases and associated intake of medications that may affect nutrient utilization. Social and economic conditions can adversely affect dietary choices and eating patterns. Physiological functions naturally decline with age, which may influence absorption and metabolism. Loneliness and reluctance to eat may complicate an already marginal situation. This article reviews specific trace metals in relation to the elderly. Our objectives are to provide Dietary Reference Intakes for older adults, to provide information on presenting features and functional consequences of trace metal deficiency, and to discuss potential effects and/or benefits of trace metal supplementation in the elderly.
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Affiliation(s)
- Craig J McClain
- Department of Internal Medicine, University of Louisville Medical Center, 550 S. Jackson Street, ACB 3rd Floor, Louisville, KY 40292, USA.
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