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Karim MR, Fisher CR, Kapphahn RJ, Polanco JR, Ferrington DA. Investigating AKT activation and autophagy in immunoproteasome-deficient retinal cells. PLoS One 2020; 15:e0231212. [PMID: 32275682 PMCID: PMC7147741 DOI: 10.1371/journal.pone.0231212] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/18/2020] [Indexed: 12/04/2022] Open
Abstract
Two major proteolytic systems, the proteasome and the autophagy pathway, are key components of the proteostasis network. The immunoproteasome, a proteasome subtype, and autophagy are upregulated under stress conditions, forming a coordinated unit designed to minimize the effect of cell stress. We investigated how genetic ablation of the LMP2 immunoproteasome subunit affects autophagy in retinal pigment epithelium (RPE) from WT and LMP2 knockout mice. We monitored autophagy regulation by measuring LC3, phosphorylation of AKT (S473), and phosphorylation of S6, a downstream readout of AKT (mTOR) pathway activation. We also evaluated transcription factor EB (TFEB) nuclear translocation, a transcription factor that controls expression of autophagy and lysosome genes. WT and LMP2 KO cells were monitored after treatment with EBSS to stimulate autophagy, insulin to stimulate AKT, or an AKT inhibitor (trehalose or MK-2206). Under basal conditions, we observed hyper-phosphorylation of AKT and S6, as well as lower nuclear-TFEB content in LMP2 KO RPE compared with WT. AKT inhibitors MK-2206 and trehalose significantly inhibited AKT phosphorylation and stimulated nuclear translocation of TFEB. Starvation and AKT inhibition upregulated autophagy, albeit to a lesser extent in LMP2 KO RPE. These data support the idea that AKT hyper-activation is an underlying cause of defective autophagy regulation in LMP2 KO RPE, revealing a unique link between two proteolytic systems and a previously unknown function in autophagy regulation by the immunoproteasome.
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Affiliation(s)
- Md. Razaul Karim
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Cody R. Fisher
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jorge R. Polanco
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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2
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Sun Y, Zheng Y, Wang C, Liu Y. Glutathione depletion induces ferroptosis, autophagy, and premature cell senescence in retinal pigment epithelial cells. Cell Death Dis 2018; 9:753. [PMID: 29988039 PMCID: PMC6037763 DOI: 10.1038/s41419-018-0794-4] [Citation(s) in RCA: 329] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/09/2018] [Accepted: 06/14/2018] [Indexed: 12/28/2022]
Abstract
Glutathione (GSH) protects against oxidative damage in many tissues, including retinal pigment epithelium (RPE). Oxidative stress-mediated senescence and death of RPE and subsequent death of photoreceptors have been observed in age-related macular degeneration (AMD). Although the consequences of GSH depletion have been described previously, questions remain regarding the molecular mechanisms. We herein examined the downstream effects of GSH depletion on stress-induced premature senescence (SIPS) and cell death in human RPE cells. Briefly, cultured ARPE-19 cells were depleted of GSH using: (1) incubation in cystine (Cys2)-free culture medium; (2) treatment with buthionine sulphoximine (BSO, 1000 µM) to block de novo GSH synthesis for 24-48 h; or (3) treatment with erastin (10 µM for 12-24 h) to inhibit Cys2/glutamate antiporter (system xc-). These treatments decreased cell viability and increased both soluble and lipid reactive oxygen species (ROS) generation but did not affect mitochondrial ROS or mitochondrial mass. Western blot analysis revealed decreased expression of ferroptotic modulator glutathione peroxidase 4 (GPX4). Increased autophagy was apparent, as reflected by increased LC3 expression, autophagic vacuoles, and autophagic flux. In addition, GSH depletion induced SIPS, as evidenced by increased percentage of the senescence-associated β-galactosidase-positive cells, increased senescence-associated heterochromatin foci (SAHF), as well as cell cycle arrest at the G1 phase. GSH depletion-dependent cell death was prevented by selective ferroptosis inhibitors (8 μM Fer-1 and 600 nM Lip-1), iron chelator DFO (80 μM), as well as autophagic inhibitors Baf-A1 (75 nM) and 3-MA (10 mM). Inhibiting autophagy with Baf-A1 (75 nM) or 3-MA (10 mM) promoted SIPS. In contrast, inducing autophagy with rapamycin (100 nM) attenuated SIPS. Our findings suggest that GSH depletion induces ferroptosis, autophagy, and SIPS. In addition, we found that autophagy is activated in the process of ferroptosis and reduces SIPS, suggesting an essential role of autophagy in ferroptosis and SIPS.
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Affiliation(s)
- Yun Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yingfeng Zheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Chunxiao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
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3
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Mat Nor N, Guo CX, Rupenthal ID, Chen YS, Green CR, Acosta ML. Sustained Connexin43 Mimetic Peptide Release From Loaded Nanoparticles Reduces Retinal and Choroidal Photodamage. Invest Ophthalmol Vis Sci 2018; 59:3682-3693. [PMID: 30029255 DOI: 10.1167/iovs.17-22829] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose To evaluate the long-term effect on inflammation and inflammasome activation of intravitreally delivered connexin43 mimetic peptide (Cx43MP) in saline or incorporated within nanoparticles (NPs) for the treatment of the light-damaged rat eye. Methods Light-induced damage to the retina was created by exposure of adult albino Sprague-Dawley rats to intense light for 24 hours. A single dose of Cx43MP, Cx43MP-NPs, or saline was injected intravitreally at 2 hours after onset of light damage. Fluorescein isothiocyanate (FITC)-labelled Cx43MP-NPs were intravitreally injected to confirm delivery into the retina. Electroretinogram (ERG) recordings were performed at 24 hours, 1 week, and 2 weeks post cessation of light damage. The retinal and choroidal layers were analyzed in vivo using optical coherence tomography (OCT) and immunohistochemistry was performed on harvested tissues using glial fibrillary acidic protein (GFAP), leukocyte common antigen (CD45), and Cx43 antibodies. Results FITC was visualized 30 minutes after injection in the ganglion cell layer and in the choroid. Cx43MP and Cx43MP-NP treatments improved a-wave and b-wave function of the ERG compared with saline-injected eyes at 1 week and 2 weeks post treatment, and prevented photoreceptor loss by 2 weeks post treatment. Inflammation was also reduced and this was in parallel with downregulation of Cx43 expression. Conclusions The slow release of Cx43MP incorporated into NPs is more effective at treating retinal injury than a single dose of native Cx43MP in solution by reducing inflammation and maintaining both retinal structure and function. This NP preparation has clinical relevance as it reduces possible ocular complications associated with repeated intravitreal injections.
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Affiliation(s)
- Nasir Mat Nor
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,Faculty of Medicine, University of Sultan Zainal Abidin, Kuala Terengganu, Malaysia.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Cindy X Guo
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Ilva D Rupenthal
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, University of Auckland, Auckland, New Zealand.,Buchanan Ocular Therapeutics Unit, University of Auckland, Auckland, New Zealand
| | - Ying-Shan Chen
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, University of Auckland, Auckland, New Zealand.,Buchanan Ocular Therapeutics Unit, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Monica L Acosta
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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4
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Tasharrofi N, Kouhkan F, Soleimani M, Soheili ZS, Kabiri M, Mahmoudi Saber M, Dorkoosh FA. Survival Improvement in Human Retinal Pigment Epithelial Cells via Fas Receptor Targeting by miR-374a. J Cell Biochem 2017; 118:4854-4861. [PMID: 28543858 DOI: 10.1002/jcb.26160] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 05/22/2017] [Indexed: 01/09/2023]
Abstract
Oxidative conditions of the eye could contribute to retinal cells loss through activating the Fas-L/Fas pathway. This phenomenon is one of the leading causes of some ocular diseases like age-related macular degeneration (AMD). By targeting proteins at their mRNA level, microRNAs (miRNAs) can regulate gene expression and cell function. The aim of the present study is to investigate Fas targeting by miR-374a and find whether it can inhibit Fas-mediated apoptosis in primary human retinal pigment epithelial (RPE) cells under oxidative stress. So, the primary human RPE cells were transfected with pre-miR-374a pLEX construct using polymeric carrier and were exposed to H2 O2 (200 μM) as an oxidant agent for induction of Fas expression. Fas expression at mRNA and protein level was evaluated by quantitative real-time PCR and Western blot analysis, respectively. These results revealed that miR-374a could prevent Fas upregulation under oxidative conditions. Moreover, Luciferase activity assay confirmed that Fas could be a direct target of miR-374a. The cell viability studies demonstrated that caspase-3 activity was negligible in miR-374a treated cells compared to the controls. Our data suggest miR-374a is a negative regulator of Fas death receptor which is able to enhance the cell survival and protect RPE cells against oxidative conditions. J. Cell. Biochem. 118: 4854-4861, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Nooshin Tasharrofi
- Faculty of Pharmacy, Department of Pharmaceutical Nanotechnology, Tehran University of Medical Sciences, Tehran, Iran
- Faculty of Pharmacy, Department of Pharmaceutics, Tehran University of Medical Science, Tehran, Iran
- Stem Cell Technology Research Center, Tehran, Iran
| | | | - Masoud Soleimani
- Faculty of Medical Science, Department of Hematology, Tarbiat Modares University, Tehran, Iran
| | - Zahra-Sheila Soheili
- Faculty of Molecular Medicine, Institute of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mahboubeh Kabiri
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| | - Mohaddeseh Mahmoudi Saber
- Faculty of Pharmacy, Department of Pharmaceutical Nanotechnology, Tehran University of Medical Sciences, Tehran, Iran
- Faculty of Pharmacy, Department of Pharmaceutics, Tehran University of Medical Science, Tehran, Iran
- Faculty of Pharmacy, Nanotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Farid Abedin Dorkoosh
- Faculty of Pharmacy, Department of Pharmaceutics, Tehran University of Medical Science, Tehran, Iran
- Faculty of Pharmacy, Medical Biomaterial Research Center (MBRC), Tehran University of Medical Science, No. 1462, Kargar Ave, Tehran, Iran
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Carver KA, Lin CM, Bowes Rickman C, Yang D. Lack of the P2X 7 receptor protects against AMD-like defects and microparticle accumulation in a chronic oxidative stress-induced mouse model of AMD. Biochem Biophys Res Commun 2016; 482:81-86. [PMID: 27810364 DOI: 10.1016/j.bbrc.2016.10.140] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 10/29/2016] [Indexed: 12/17/2022]
Abstract
The P2X7 receptor (P2X7R) is an ATP-gated ion channel that is a key player in oxidative stress under pathological conditions. The P2X7R is expressed in the retinal pigmented epithelium (RPE) and neural retina. Chronic oxidative stress contributes to the pathogenesis of age-related macular degeneration (AMD). Mice lacking Cu, Zn superoxide dismutase (Sod1) developed chronic oxidative stress as well as AMD-like features, but whether the P2X7R plays a causative role in oxidative stress-induced AMD is unknown. Thus, the main purpose of this study was to test if concurrent knockout (KO) of P2X7R could block AMD-like defects seen in Sod1 KO mice. Using multiple approaches, we demonstrate that Sod1 KO causes AMD-like defects, including positive staining for oxidative stress markers, 3-nitrotyrosine and carboxymethyl lysine, thinning of the RPE and retina, thickening of Bruch's membrane, presence of basal laminar and linear deposits, RPE barrier disruption and accumulation of microglia/macrophages. Moreover, we find that Sod1 KO mice accumulate more microparticles (MPs) within RPE/choroid tissues. Concurrent KO of the P2X7R protects against AMD-like defects and MP accumulation in Sod1 KO mice. Together, we show for the first time, that deficiency of P2X7R prevents in vivo oxidative stress-induced accumulation of MPs and AMD-like defects. This work could potentially lead to novel therapies for AMD and other oxidative stress-driven diseases.
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Affiliation(s)
- Kyle A Carver
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - C M Lin
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Catherine Bowes Rickman
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27710, USA; Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA.
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Schuld NJ, Hussong SA, Kapphahn RJ, Lehmann U, Roehrich H, Rageh AA, Heuss ND, Bratten W, Gregerson DS, Ferrington DA. Immunoproteasome deficiency protects in the retina after optic nerve crush. PLoS One 2015; 10:e0126768. [PMID: 25978061 PMCID: PMC4433222 DOI: 10.1371/journal.pone.0126768] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/07/2015] [Indexed: 01/31/2023] Open
Abstract
The immunoproteasome is upregulated by disease, oxidative stress, and inflammatory cytokines, suggesting an expanded role for the immunoproteasome in stress signaling that goes beyond its canonical role in generating peptides for antigen presentation. The signaling pathways that are regulated by the immunoproteasome remain elusive. However, previous studies suggest a role for the immunoproteasome in the regulation of PTEN and NF-κB signaling. One well-known pathway upstream of NF-κB and downstream of PTEN is the Akt signaling pathway, which is responsible for mediating cellular survival and is modulated after optic nerve crush (ONC). This study investigated the role of retinal immunoproteasome after injury induced by ONC, focusing on the Akt cell survival pathway. Retinas or retinal pigment epithelial (RPE) cells from wild type (WT) and knockout (KO) mice lacking either one (LMP2) or two (LMP7 and MECL-1) catalytic subunits of the immunoproteasome were utilized in this study. We show that mRNA and protein levels of the immunoproteasome subunits are significantly upregulated in WT retinas following ONC. Mice lacking the immunoproteasome subunits show either a delayed or dampened apoptotic response as well as altered Akt signaling, compared to WT mice after ONC. Treatment of the RPE cells with insulin growth factor-1 (IGF-1) to stimulate Akt signaling confirmed that the immunoproteasome modulates this pathway, and most likely modulates parallel pathways as well. This study links the inducible expression of the immunoproteasome following retinal injury to Akt signaling, which is important in many disease pathways.
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Affiliation(s)
- Nathan J. Schuld
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Stacy A. Hussong
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ute Lehmann
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- Graduate Program in Microbiology, Immunology and Cancer Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Heidi Roehrich
- Histology Core for Vision Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Abrar A. Rageh
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Wendy Bratten
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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7
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Chen J, Hu R, Ge H, Duanmu W, Li Y, Xue X, Hu S, Feng H. G-protein-coupled receptor 30-mediated antiapoptotic effect of estrogen on spinal motor neurons following injury and its underlying mechanisms. Mol Med Rep 2015; 12:1733-40. [PMID: 25872489 PMCID: PMC4464192 DOI: 10.3892/mmr.2015.3601] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 03/12/2015] [Indexed: 12/24/2022] Open
Abstract
Spinal cord injury (SCI) may result in severe dysfunction of motor neurons. G-protein-coupled receptor 30 (GPR30) expression in the motor neurons of the ventral horn of the spinal cord mediates neuroprotection through estrogen signaling. The present study explored the antiapoptotic effect of estrogen, mediated by GPR30 following SCI, and the mechanisms underlying this effect. Spinal motor neurons from rats were cultured in vitro in order to establish cell models of oxygen and glucose deprivation (OGD). The effects of estrogen, the estrogen agonist, G1, and the estrogen inhibitor, G15, on motor neurons were observed using MTT assays. The effects of E2, G1 and G15 on spinal motor neuron apoptosis following OGD, were detected using flow cytometry. The role of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) inhibitor, LY294002, was also determined using flow cytometry. Rat SCI models were established. E2, G1 and E2+LY294002 were administered in vivo. Motor function was scored at 3, 7, 14, 21 and 28 d following injury, using Basso-Beattie-Bresnahan (BBB) standards. Cell activity in the estrogen and G1 groups was higher than that in the solvent group, whereas cell activity in the E2+G15 group was lower than that in the E2 group (P<0.05). Following OGD, the proportion of apoptotic cells significantly increased (P<0.05). The proportion in the estrogen group was significantly lower than that in the solvent group, whereas the proportion of apoptotic cells in the E2+G15 and E2+LY294002 groups was higher than that in the E2 group (P<0.05). Treatment with E2 and G1 led to upregulation of P-Akt expression in normal cells and post-OGD cells. The BBB scores of rats in the E2 and G1 groups were higher than those in the placebo group (P<0.05). The BBB scores of the E2+LY294002 group were lower than those of the E2 group (P<0.05). Estrogen thus appears to exert a protective effect on spinal motor neurons following OGD, via GPR30. The PI3K/Akt pathway may be one of those involved in the estrogen-related antiapoptotic effects mediated by GPR30.
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Affiliation(s)
- Jingyu Chen
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Rong Hu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Hongfei Ge
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Wangsheng Duanmu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Yuhong Li
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Xingseng Xue
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Shengli Hu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, P.R. China
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8
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Liu L, Lao W, Ji QS, Yang ZH, Yu GC, Zhong JX. Lycium barbarum polysaccharides protected human retinal pigment epithelial cells against oxidative stress-induced apoptosis. Int J Ophthalmol 2015; 8:11-6. [PMID: 25709900 PMCID: PMC4325234 DOI: 10.3980/j.issn.2222-3959.2015.01.02] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 10/27/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To investigate the protective effect and its mechanism of lycium barbarum polysaccharides (LBP) against oxidative stress-induced apoptosis in human retinal pigment epithelial cells. METHODS ARPE-19 cells, a human retinal pigment epithelial cell lines, were exposed to different concentrations of H2O2 for 24h, then cell viability was measured by Cell Counting Kit-8 (CCK-8) assay to get the properly concentration of H2O2 which can induce half apoptosis of APRE-19. With different concentrations of LBP pretreatment, the ARPE-19 cells were then exposed to appropriate concentration of H2O2, cell apoptosis was detected by flow cytometric analysis. Expression levels of Bcl-2 and Bax were measured by real time quantitative polymerase chain reaction (RT-PCR) technique. RSULTS LBP significantly reduced the H2O2-induced ARPE-19 cells' apoptosis. LBP inhibited the H2O2-induced down-regulation of Bcl-2 and up-regulation of Bax. CONCLUSION LBP could protect ARPE-19 cells from H2O2-induced apoptosis. The Bcl-2 family had relationship with the protective effects of LBP.
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Affiliation(s)
- Lian Liu
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
| | - Wei Lao
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
| | - Qing-Shan Ji
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
| | - Zhi-Hao Yang
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
| | - Guo-Cheng Yu
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
| | - Jing-Xiang Zhong
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, Guangdong Province, China
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9
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Liu Y, Zhang Y, Gu Z, Hao L, Du J, Yang Q, Li S, Wang L, Gong S. Cholecystokinin octapeptide antagonizes apoptosis in human retinal pigment epithelial cells. Neural Regen Res 2014; 9:1402-8. [PMID: 25221599 PMCID: PMC4160873 DOI: 10.4103/1673-5374.137596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2014] [Indexed: 11/13/2022] Open
Abstract
Although cholecystokinin octapeptide-8 is important for neurological function, its neuroprotective properties remain unclear. We speculated that cholecystokinin octapeptide-8 can protect human retinal pigment epithelial cells against oxidative injury. In this study, retinal pigment epithelial cells were treated with peroxynitrite to induce oxidative stress. Peroxynitrite triggered apoptosis in these cells, and increased the expression of Fas-associated death domain, Bax, caspa-se-8 and Bcl-2. These changes were suppressed by treatment with cholecystokinin octapeptide-8. These results suggest that cholecystokinin octapeptide-8 can protect human retinal pigment epithelial cells against apoptosis induced by peroxynitrite.
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Affiliation(s)
- Yuan Liu
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Yueling Zhang
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Zhaohui Gu
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Lina Hao
- Department of Ophthalmology, Hebei Province People's Hospital, Shijiazhuang, Hebei Province, China
| | - Juan Du
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Qian Yang
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Suping Li
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Liying Wang
- Department of Ophthalmology, First Central Hospital of Baoding, Baoding, Hebei Province, China
| | - Shilei Gong
- Department of Endoscope Room, First Central Hospital of Baoding, Baoding, Hebei Province, China
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11
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Induction of necrotic cell death by oxidative stress in retinal pigment epithelial cells. Cell Death Dis 2013; 4:e965. [PMID: 24336085 PMCID: PMC3877549 DOI: 10.1038/cddis.2013.478] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 10/22/2013] [Indexed: 12/11/2022]
Abstract
Age-related macular degeneration (AMD) is a degenerative disease of the retina and the leading cause of blindness in the elderly. Retinal pigment epithelial (RPE) cell death and the resultant photoreceptor apoptosis are characteristic of late-stage dry AMD, especially geographic atrophy (GA). Although oxidative stress and inflammation have been associated with GA, the nature and underlying mechanism for RPE cell death remains controversial, which hinders the development of targeted therapy for dry AMD. The purpose of this study is to systematically dissect the mechanism of RPE cell death induced by oxidative stress. Our results show that characteristic features of apoptosis, including DNA fragmentation, caspase 3 activation, chromatin condensation and apoptotic body formation, were not observed during RPE cell death induced by either hydrogen peroxide or tert-Butyl hydroperoxide. Instead, this kind of cell death can be prevented by RIP kinase inhibitors necrostatins but not caspase inhibitor z-VAD, suggesting necrotic feature of RPE cell death. Moreover, ATP depletion, receptor interacting protein kinase 3 (RIPK3) aggregation, nuclear and plasma membrane leakage and breakdown, which are the cardinal features of necrosis, were observed in RPE cells upon oxidative stress. Silencing of RIPK3, a key protein in necrosis, largely prevented oxidative stress-induced RPE death. The necrotic nature of RPE death is consistent with the release of nuclear protein high mobility group protein B1 into the cytoplasm and cell medium, which induces the expression of inflammatory gene TNFα in healthy RPE and THP-1 cells. Interestingly, features of pyroptosis or autophagy were not observed in oxidative stress-treated RPE cells. Our results unequivocally show that necrosis, but not apoptosis, is a major type of cell death in RPE cells in response to oxidative stress. This suggests that preventing oxidative stress-induced necrotic RPE death may be a viable approach for late-stage dry AMD.
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12
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Guo P, Wang Q, Liu J, Liu L, Zhao P, Cao Y, Liu Y, Qi C, Liu Y. Preparation of two organoselenium compounds and their induction of apoptosis to SMMC-7221 cells. Biol Trace Elem Res 2013; 154:304-11. [PMID: 23775600 DOI: 10.1007/s12011-013-9715-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/22/2013] [Indexed: 10/26/2022]
Abstract
Two organoselenium compounds: xylitol selenious ester (xylitol-Se) and sucrose selenious ester (sucrose-Se) were synthesized, and their molecular structures were characterized in this study. In MTT assay, xylitol-Se and sucrose-Se showed cytostatic effects on human hepatocellular carcinoma cells SMMC-7221 in a dose-dependent manner, whereas they had no negative influences on the proliferation of human normal hepatic cells HL-7702 in the concentration range from 0.15 to 1.2 ppm Se. Morphological observation, agarose gel electrophoresis, and caspase-3 assay indicated that xylitol-Se and sucrose-Se induced mitochondrial apoptosis to SMMC-7221 cells, which is supported by the depletion of mitochondrial membrane potential and suppression of caspase-3 activity, indicating their ability of inducing apoptosis to cancer cells and great potentials as anticancer drugs.
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Affiliation(s)
- Pei Guo
- Key Laboratory of Pesticide and Chemical Biology (Ministry of Education), College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
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Maldonado M, Kapphahn RJ, Terluk MR, Heuss ND, Yuan C, Gregerson DS, Ferrington DA. Immunoproteasome deficiency modifies the alternative pathway of NFκB signaling. PLoS One 2013; 8:e56187. [PMID: 23457524 PMCID: PMC3572990 DOI: 10.1371/journal.pone.0056187] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/10/2013] [Indexed: 11/19/2022] Open
Abstract
Immunoproteasome is a protease abundant in immune cells and also present, albeit at lower concentrations, in cells outside the immune system. Recent evidence supports a novel role for the immunoproteasome in the cellular stress response potentially through regulation of NFκB signaling, which is the primary response to multiple stressors. The current study tests whether the Classical or Alternative Pathways are regulated by immunoproteasome following chronic TNFα exposure in cultured retinal pigment epithelial cells isolated from wild-type mice and mice deficient in one (LMP2, L2) or two (LMP7 and MECL-1, L7M1) immunoproteasome subunits. Assays were performed to assess the expression of NFκB responsive genes, the content and activity of NFκB transcription factors (p65, p50, p52, cRel, RelB), and expression and content of regulatory proteins (IκBα, A20, RPS3). Major findings include distinct differences in expression of NFκB responsive genes in both KO cells. The mechanism responsible for the altered gene expression could not be established for L7M1 since no major differences in NFκB transcription factor content or activation were observed. However, L2 cells exhibited substantially higher content and diminished activation of NFκB transcription factors associated with the Alternative Pathway and delayed termination of the Classical Pathway. These results provide strong experimental evidence supporting a role for immunoproteasome in modulating NFκB signaling.
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Affiliation(s)
- Marcela Maldonado
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Rebecca J. Kapphahn
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Marcia R. Terluk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Neal D. Heuss
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ching Yuan
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dale S. Gregerson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Hao L, Zhang X, Yang T, Ma J. Puerarin antagonizes peroxyntrite-induced injury in retinal pigment epithelial cells. Neural Regen Res 2012; 7:669-74. [PMID: 25745461 PMCID: PMC4347006 DOI: 10.3969/j.issn.1673-5374.2012.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 02/22/2012] [Indexed: 01/28/2023] Open
Abstract
A rat model of diabetes mellitus was established by intraperitoneal injection of streptozotocin. Three days later, the rats were intraperitoneally administered 140 mg puerarin/kg daily, for a total of 60 successive days. DNA ladder results showed increased apoptosis over time in retinal pigment epithelial cells from rats with streptozotocin-induced diabetes mellitus. Western blot analysis, Reverse transcription-PCR, immunohistochemistry, and flow cytometry results showed increased expression of 3-nitrotyrosine, a peroxyntrite marker, as well as inducible nitric synthase and Fas/FasL, in retinal pigment epithelial cells. Puerarin reversed these changes, and results demonstrated that puerarin inhibited Fas/FasL expression and alleviated peroxyntrite injury to retinal pigment epithelial cells. These results suggested that puerarin inhibited production of inducible nitric oxide synthase and directly antagonized peroxyntrite injury in retinal pigment epithelial cells.
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Affiliation(s)
- Lina Hao
- Ophthalmology Department, Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Xudong Zhang
- Pharmaceutical Department, Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Tao Yang
- Internal Department, the First Hospital, Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
| | - Junling Ma
- Ophthalmology Department, Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
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Hao LN, Wang M, Zhang XD, Yang T. Control of peroxyntrite-induced production of inducible nitric oxide synthase isoforms and antagonism of cholecystokinin octapeptide -8 in retinal pigment epithelial cells in vivo. Int J Ophthalmol 2011; 4:605-10. [PMID: 22553729 PMCID: PMC3340793 DOI: 10.3980/j.issn.2222-3959.2011.06.06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 11/24/2011] [Indexed: 11/02/2022] Open
Abstract
AIM To explore if peroxyntrite (ONOO(-)) induced iNOS via Fas/Fas/L pathway in diabetic rats and the effection of cholecystokinin octapeptide-8 (CCK-8) as therapeutic agent for decrease diabetic retinopathy. METHODS Thirty-six rats were taken as control group, seventy two were given (streptozotocin) STZ (45mg/kg) and then divided into ONOO(-) group and CCK-8 group (peritoneal injection CCK-8). STZ-induced diabetic rats were treated with CCK-8 for 60 days. Western blotting analysis, DNA ladder, RT-PCR, immunohistochemistry and flow cytometry were used for determining the expression of nitrotyrosine (NT, the foot print of ONOO(-)); apoptosis and inducible nitric oxide synthase (iNOS) mRNA as well as Fas/Fasl signal transduction in RPE cells. RESULTS Both RPE cells in ONOO(-) and CCK-8 group developed apoptosis and expressed NT, iNOS mRNA and Fas/Fasl. But latter delayed the all changes in a time-dependent manner compared with control and ONOO(-) group (P<0.001). iNOS and Fas/Fasl were up-regulated and associated with an increase of expression of ONOO(-)in vivo. CONCLUSION The study suggested that apoptosis of RPE was partly induced by ONOO(-) may be the new way of oxidative damage to the RPE cells. CCK-8 decreased RPE cells apoptosis partly induced by ONOO(-) and is a potential drug for therapy of diabetic retinopathy. The mechanism of CCK-8 dealing with RPE cells may be related to its direct inhibition of the formation of iNOS to produce ONOO(-) and antagnism of damage of ONOO(-) to RPE cells.
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Affiliation(s)
- Li-Na Hao
- Ophthalmology Department of Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Min Wang
- Ophthalmology Department of Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Xu-Dong Zhang
- Pharmacology Department of Hebei Province People's Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Tao Yang
- Internal Department of First Hospital affiliated to Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
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Dwyer MA, Kazmin D, Hu P, McDonnell DP, Malek G. Research resource: nuclear receptor atlas of human retinal pigment epithelial cells: potential relevance to age-related macular degeneration. Mol Endocrinol 2011; 25:360-72. [PMID: 21239617 DOI: 10.1210/me.2010-0392] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Retinal pigment epithelial (RPE) cells play a vital role in retinal physiology by forming the outer blood-retina barrier and supporting photoreceptor function. Retinopathies including age-related macular degeneration (AMD) involve physiological and pathological changes in the epithelium, severely impairing the retina and effecting vision. Nuclear receptors (NRs), including peroxisome proliferator-activated receptor and liver X receptor, have been identified as key regulators of physiological pathways such as lipid metabolic dysregulation and inflammation, pathways that may also be involved in development of AMD. However, the expression levels of NRs in RPE cells have yet to be systematically surveyed. Furthermore, cell culture lines are widely used to study the biology of RPE cells, without knowledge of the differences or similarities in NR expression and activity between these in vitro models and in vivo RPE. Using quantitative real-time PCR, we assessed the expression patterns of all 48 members of the NR family plus aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator in human RPE cells. We profiled freshly isolated cells from donor eyes (in vivo), a spontaneously arising human cell line (in vitro), and primary cell culture lines (in vitro) to determine the extent to which NR expression in the cultured cell lines reflects that of in vivo. To evaluate the validity of using cell culture models for investigating NR receptor biology, we determined transcriptional activity and target gene expression of several moderately and highly expressed NRs in vitro. Finally, we identified a subset of NRs that may play an important role in pathobiology of AMD.
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Affiliation(s)
- Mary A Dwyer
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710, USA
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Hao LN, Zhang YQ, Shen YH, Wang ZY, Wang YH, Zhang HF, He SZ. Effect of puerarin on retinal pigment epithelial cells apoptosis induced partly by peroxynitrite via Fas/FasL pathway. Int J Ophthalmol 2010; 3:283-7. [PMID: 22553574 PMCID: PMC3340750 DOI: 10.3980/j.issn.2222-3959.2010.04.01] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 11/15/2010] [Indexed: 11/02/2022] Open
Abstract
AIM To evaluate the peroxynitrite (ONOO(-)) of puerarin on retinal pigment epithelial (RPE) cells apoptosis induced partly by peroxynitrite via Fas/FasL. METHODS RPE cells from C57BL/6 mice eyes were cultured. Diabetes was induced in Sprague-Dawley (SD) rats by streptozotocin (STZ) intraperitoneal injection. Puerarin was administrated to cultured RPE cells and diabetic rats. Western blotting analysis, DNA ladder, RT-PCR, immunohistochemistry were used for determining the expression of nitrotyrosine (NT, the foot print of ONOO(-)), complement 3 (C3); apoptosis and inducible nitric oxide synthase (iNOS) mRNA as well as Fas/FasL signal transduction in RPE cells. RESULTS Both RPE cells in ONOO(-) and puerarin group developed apoptosis and expressed NT, C3, iNOS mRNA and Fas/FasL. But latter delayed the all changes in a time-dependent manner compared with control and STZ group (P<0.001). iNOS, C3 and Fas/FasL were up-regulated and associated with an increase of expression of ONOO(-)in vivo and in vitro. CONCLUSION Puerarin decreases RPE cells apoptosis partly induced by ONOO(-) for diabetic retinopathy.
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Affiliation(s)
- Li-Na Hao
- Department of Ophthalmology, People's Hospital of Hebei Province, Shijiazhuang 050051, Hebei Province, China
| | - Yan-Qing Zhang
- Department of Ophthalmology, Chengde County Hospital, Chengde 067400, Hebei Province, China
| | - Yu-Hua Shen
- Department of Ophthalmology, Eye Hospital of Handan, Handan 056001, Hebei Province, China
| | - Zhi-Yun Wang
- Department of Ophthalmology, Chengde County Hospital, Chengde 067400, Hebei Province, China
| | - Yan-Hua Wang
- Department of Ophthalmology, Chengde County Hospital, Chengde 067400, Hebei Province, China
| | - Hai-Fang Zhang
- Department of Ophthalmology, People's Hospital of Hebei Province, Shijiazhuang 050051, Hebei Province, China
| | - Shou-Zhi He
- Department of Ophthalmology, Chinese PLA Hospital, Beijing 100853, China
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Valenti DA. Alzheimer's disease: visual system review. ACTA ACUST UNITED AC 2010; 81:12-21. [PMID: 20004873 DOI: 10.1016/j.optm.2009.04.101] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 03/09/2009] [Accepted: 04/29/2009] [Indexed: 01/16/2023]
Abstract
BACKGROUND Ten million baby boomers in the United States will get Alzheimer's disease. Optometrists can benefit from understanding the impact the Alzheimer's disease process has on the visual system. This can result in more effective management of the condition and in more effective communication with members of the Alzheimer's disease multidisciplinary team. METHODS This is a review of the literature but by no means a completely exhaustive review. Alzheimer's disease is a complex disease. A rapidly expanding body of knowledge covers multiple disciplines. RESULTS The visual system shows deficits early in the degenerative process of Alzheimer's disease. Biomarkers through the visual system such as nerve fiber deficits, lens opacities, and functional losses in the magnocellular pathway, such as contrast sensitivity and temporal processing, may prove to not only help detect Alzheimer's disease early but also detect it before there are the classic cognitive and memory losses. CONCLUSIONS The effects of Alzheimer's disease are devastating. Optometrists, as primary care clinicians, can make critical contributions in the diagnosis, treatment, and management of this neurodegenerative disease.
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Affiliation(s)
- Denise A Valenti
- Harvard Vanguard Medical Associates, Braintree, Massachusetts, USA.
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Hussong SA, Kapphahn RJ, Phillips SL, Maldonado M, Ferrington DA. Immunoproteasome deficiency alters retinal proteasome's response to stress. J Neurochem 2010; 113:1481-90. [PMID: 20345760 DOI: 10.1111/j.1471-4159.2010.06688.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our previous work demonstrated that immunoproteasome is up-regulated in the retina and brain in response to injury that does not involve an inflammatory response (J. Neurochem. 2008; 106:158). These results suggest additional non-immune functions for the immunoproteasome in the cellular stress response pathway. The present study further investigates the potential involvement of the immunoproteasome in responding to the chronic stress of aging or oxidant exposure in the retina and cultured retinal pigment epithelial (RPE) cells from knock-out mice missing either one (lmp7(-/-)) or two (lmp7(-/-)/mecl-1(-/-)) immunoproteasome subunits. We show that aging and chronic oxidative stress up-regulates immunoproteasome in the retina and RPE from wild-type mice. No up-regulation of LMP2 was observed in retinas or RPE lacking MECL-1 and/or LMP7, suggesting that the full complement of immunoproteasome subunits is required to achieve maximal up-regulation in response to stress. We also show that RPE deficient in immunoproteasome are more susceptible to oxidation-induced cell death, supporting a role for immunoproteasome in protecting from oxidative stress. These results provide key mechanistic insight into novel aspects of proteasome biology and are an important first step in identifying alternative roles for retinal immunoproteasome that are unrelated to its role in the immune response.
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Affiliation(s)
- Stacy A Hussong
- Department of Ophthalmology, University of Minnesota, Minneapolis, MN, USA
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Schmitz-Valckenberg S, Guo L, Cheung W, Moss S, Fitzke F, Cordeiro M. In-vivo-Imaging retinaler Zellapoptose nach akuter Lichtexposition. Ophthalmologe 2009; 107:22-9. [DOI: 10.1007/s00347-009-1952-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Yang D, Elner SG, Lin LR, Reddy VN, Petty HR, Elner VM. Association of superoxide anions with retinal pigment epithelial cell apoptosis induced by mononuclear phagocytes. Invest Ophthalmol Vis Sci 2009; 50:4998-5005. [PMID: 19458341 DOI: 10.1167/iovs.09-3620] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Oxidative stress of the retinal pigment epithelium by reactive oxygen species and monocytic infiltration have been implicated in age-related macular degeneration. The purpose of this study was to determine the role of superoxide anions (O(2)(-)) in mononuclear phagocyte-induced RPE apoptosis. METHODS Mouse RPE cell cultures were established from wild-type and heterozygous superoxide dismutase 2-knockout (Sod2(+/-)) mice. The intracellular reactive oxygen species, O(2)(-) and hydrogen peroxide, were measured by using dihydroethidium assay and 5-(and 6)-chloromethyl-2',7'-dichlorodihydrofluorescence diacetate, acetyl ester assay, respectively. RPE apoptosis was evaluated by Hoechst staining and terminal deoxynucleotidyltransferase dUTP nick-end labeling assay. Changes in mitochondrial membrane potential were detected by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide dye. Activated caspases and caspase-3 were detected in situ by FITC-VAD-fmk staining and caspase-3 substrate, respectively. RESULTS Mononuclear phagocytes and interferon-gamma-activated mononuclear phagocytes induced the production of intracellular RPE O(2)(-), a decrease in RPE mitochondrial membrane potential, caspase activation, and apoptosis of mouse RPE cells. All theses changes were significantly enhanced in the Sod2(+/-) RPE cells. Activated mononuclear phagocytes induced more of these oxidative and apoptotic changes in RPE cells than did unstimulated mononuclear phagocytes. CONCLUSIONS The authors have shown that the decreased expression of SOD2 and increased superoxide production correlate with RPE apoptosis induced by unstimulated and activated mononuclear phagocytes. The authors suggest that elevated O(2)(-) levels due to genetic abnormalities of SOD2 or immunologic activation of mononuclear phagocytes lead to greater levels of RPE apoptosis. The present study could serve as a useful model to characterize RPE/phagocyte interaction in AMD and other retinal diseases.
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Affiliation(s)
- Dongli Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan 48105-0714, USA
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22
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Fujihara M, Nagai N, Sussan TE, Biswal S, Handa JT. Chronic cigarette smoke causes oxidative damage and apoptosis to retinal pigmented epithelial cells in mice. PLoS One 2008; 3:e3119. [PMID: 18769672 PMCID: PMC2518621 DOI: 10.1371/journal.pone.0003119] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 08/13/2008] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study was to determine whether mice exposed to chronic cigarette smoke develop features of early age-related macular degeneration (AMD). Two month old C57Bl6 mice were exposed to either filtered air or cigarette smoke in a smoking chamber for 5 h/day, 5 days/week for 6 months. Eyes were fixed in 2.5% glutaraldehyde/2% paraformaldehyde and examined for ultrastructural changes by transmission electron microscopy. The contralateral eye was fixed in 2% paraformaldehyde and examined for oxidative injury to the retinal pigmented epithelium (RPE) by 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-OHdG) immunolabeling and apoptosis by TUNEL labeling. Mice exposed to cigarette smoke had immunolabeling for 8-OHdG in 85±3.7% of RPE cells counted compared to 9.5±3.9% in controls (p<0.00001). Bruch membrane was thicker in mice exposed to smoke (1086±332 nm) than those raised in air (543±132 nm; p = 0.0069). The two most pronounced ultrastructural changes (severity grading scale from 0–3) seen were a loss of basal infoldings (mean difference in grade = 1.98; p<0.0001), and an increase in intracellular vacuoles (mean difference in grade = 1.7; p<0.0001). Ultrastructural changes to Bruch membrane in cigarette-smoke exposed mice were smaller in magnitude but consistently demonstrated significantly higher grade injury in cigarette-exposed mice, including basal laminar deposits (mean difference in grade = 0.54; p<0.0001), increased outer collagenous layer deposits (mean difference in grade = 0.59; p = 0.002), and increased basal laminar deposit continuity (mean difference in grade = 0.4; p<0.0001). TUNEL assay showed a higher percentage of apoptotic RPE from mice exposed to cigarette smoke (average 8.0±1.1%) than room air (average 0±0%; p = 0.043). Mice exposed to chronic cigarette smoke develop evidence of oxidative damage with ultrastructural degeneration to the RPE and Bruch membrane, and RPE cell apoptosis. This model could be useful for studying the mechanism of smoke induced changes during early AMD.
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Affiliation(s)
- Masashi Fujihara
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
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Ferrington DA, Hussong SA, Roehrich H, Kapphahn RJ, Kavanaugh SM, Heuss ND, Gregerson DS. Immunoproteasome responds to injury in the retina and brain. J Neurochem 2008; 106:158-69. [PMID: 18346202 PMCID: PMC4401486 DOI: 10.1111/j.1471-4159.2008.05345.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is well known that immunoproteasome generates peptides for MHC Class I occupancy and recognition by cytotoxic T lymphocytes (CTL). The present study focused on evidence for alternative roles for immunoproteasome. Retina and brain were analyzed for expression of immunoproteasome subunits using immunohistochemistry and western blotting under normal conditions and after injury/stress induced by CTL attack on glia (brain) or neurons (retina). Normal retina expressed substantial levels of immunoproteasome in glia, neurons, and retinal pigment epithelium. The basal level of immunoproteasome in retina was two-fold higher than in brain; CTL-induced retinal injury further up-regulated immunoproteasome expression. Immunoproteasome up-regulation was also observed in injured brain and corresponded with expression in Purkinje cells, microglia, astrocytes, and oligodendrocytes. These results suggest that the normal environment of the retina is sufficiently challenging to require on-going expression of immunoproteasome. Further, immunoproteasome up-regulation with retinal and brain injury implies a role in neuronal protection and/or repair of damage.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology, University of Minnesota, Minneapolis, Minnesota, USA.
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Schmitz-Valckenberg S, Guo L, Maass A, Cheung W, Vugler A, Moss SE, Munro PMG, Fitzke FW, Cordeiro MF. Real-time in vivo imaging of retinal cell apoptosis after laser exposure. Invest Ophthalmol Vis Sci 2008; 49:2773-80. [PMID: 18281610 DOI: 10.1167/iovs.07-1335] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate whether the detection of apoptosing retinal cells (DARC) could detect cells undergoing apoptosis in a laser model of retinal damage. METHODS Laser lesions were placed, with the use of a frequency-doubled Nd:YAG laser, on the retina in 34 eyes of anesthetized Dark Agouti rats. Lesion size and laser-induced retinal elevation were analyzed using in vivo reflectance imaging. Development of retinal cell apoptosis was assessed using intravitreal fluorescence-labeled annexin 5 in vivo with DARC technology from baseline until 90 minutes after laser application. Histologic analysis of retinal flat mounts and cross-sections was performed. RESULTS The lateral and anteroposterior depth extension of the zone of laser damage was significantly larger for higher exposure settings. A strong diffuse signal, concentrated at the outer retina, was seen with DARC for low exposures (<300 ms and <300 mW). In comparison, higher exposures (>300 ms and >300 mW) resulted in detectable hyperfluorescent spots, mainly at the level of the inner retinal layers. Dose-dependent effects on spot density and positive correlation of spot density between lesion size (P < 0.0001) and retinal elevation (P < 0.0001) were demonstrated. Histology confirmed the presence of apoptosing retinal cells in the inner nuclear and the ganglion cell layers. CONCLUSIONS This is the first time that DARC has been used to determine apoptotic effects in the inner nuclear layer. The ability to monitor changes spatially and temporally in vivo promises to be a major advance in the real-time assessment of retinal diseases and treatment effects.
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