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Tribble JR, Hui F, Quintero H, El Hajji S, Bell K, Di Polo A, Williams PA. Neuroprotection in glaucoma: Mechanisms beyond intraocular pressure lowering. Mol Aspects Med 2023; 92:101193. [PMID: 37331129 DOI: 10.1016/j.mam.2023.101193] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/20/2023]
Abstract
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Heberto Quintero
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Sana El Hajji
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Katharina Bell
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Eye ACP Duke-NUS, Singapore
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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Sikiric P, Kokot A, Kralj T, Zlatar M, Masnec S, Lazic R, Loncaric K, Oroz K, Sablic M, Boljesic M, Antunovic M, Sikiric S, Strbe S, Stambolija V, Beketic Oreskovic L, Kavelj I, Novosel L, Zubcic S, Krezic I, Skrtic A, Jurjevic I, Boban Blagaic A, Seiwerth S, Staresinic M. Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions. Pharmaceuticals (Basel) 2023; 16:1052. [PMID: 37513963 PMCID: PMC10385428 DOI: 10.3390/ph16071052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/01/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.
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Affiliation(s)
- Predrag Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Antonio Kokot
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia; (M.S.); (M.B.)
| | - Tamara Kralj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Mirna Zlatar
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Sanja Masnec
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Ratimir Lazic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Kristina Loncaric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Katarina Oroz
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Marko Sablic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia; (M.S.); (M.B.)
| | - Marta Boljesic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia; (M.S.); (M.B.)
| | - Marko Antunovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Suncana Sikiric
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (S.S.); (S.S.)
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Vasilije Stambolija
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Lidija Beketic Oreskovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Ivana Kavelj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Luka Novosel
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Slavica Zubcic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Anita Skrtic
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (S.S.); (S.S.)
| | - Ivana Jurjevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (T.K.); (M.Z.); (S.M.); (R.L.); (K.L.); (K.O.); (M.A.); (S.S.); (V.S.); (L.B.O.); (I.K.); (L.N.); (S.Z.); (I.K.); (I.J.); (A.B.B.)
| | - Sven Seiwerth
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (S.S.); (S.S.)
| | - Mario Staresinic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
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Abstract
Purpose: Retinal ganglion cell death occurs during the glaucoma pathological process, and it is significant because of the poor regeneration capacity of retinal ganglion cells. With a constantly increasing understanding of retinal cell death mechanisms, we now know that simply blocking a specific mechanism of cell death might not prevent retinal ganglion cell death. This review aimed to summarize the mechanisms of retinal cell death in glaucoma models and discuss the caveats in restoring visual function in these studies.Methods: A literature search was done on PubMed using key words including glaucoma, ocular hypertension, retinal ganglion cell, cell death, apoptosis, necroptosis, pyroptosis, ferroptosis, autophagic cell death, and parthanatos. The literature was reviewed to summarize the information about the lethal pathways of retinal ganglion cell in the glaucoma-like animal models.Results: Based on the purpose, 100 studies were selected and discussed in this review.Conclusions: The damage to ganglion cells in glaucoma-like animals can occur via multiple lethal pathways and the molecular mechanisms are still incompletely understood. Further investigations on the crosstalk between different cell death pathways and the common upstream regulators could augment the development of novel targeting agents for the curative treatment of glaucoma.
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Affiliation(s)
- Yuting Yang
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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Gao Z, Li M, Yao F, Xia X, Duan T, Meng J, Huang Y, He Y, Saro A, Huang J. Valdecoxib Protects against Cell Apoptosis Induced by Endoplasmic Reticulum Stress via the Inhibition of PERK-ATF4-CHOP Pathway in Experimental Glaucoma. Int J Mol Sci 2022; 23:12983. [PMID: 36361772 PMCID: PMC9657191 DOI: 10.3390/ijms232112983] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/15/2022] [Accepted: 10/20/2022] [Indexed: 07/30/2023] Open
Abstract
The purpose of this study was to investigate the effects of valdecoxib on the retina in retinal ischemia-reperfusion injury (IRI) and R28 cells following oxygen-glucose deprivation/recovery (OGD/R) injury, as well as the underlying mechanisms. Immunofluorescence and Cell Counting Kit-8 (CCK-8) analyses were used to identify the proper timepoint and concentration of valdecoxib's protective effect on the R28 cells in the OGD/R model. Hematoxylin-eosin (HE) staining and immunofluorescence were used to explore valdecoxib's effect on the retina and retina ganglion cell (RGC) in IRI. Cell apoptosis was determined by a TUNEL Apoptosis Detection Kit and Annexin V-FITC/PI flow cytometry. The expression levels of p-PERK, transcription factor 4 (ATF4), GRP78, CHOP, cleaved caspase 3, bax and bcl-2 were measured by Western blot analyses. The valdecoxib protected the R28 cells from OGD/R injury by decreasing the cell apoptosis rate, and it exerted a protective effect on retinas in I/R injury by inhibiting RGC apoptosis. The valdecoxib pretreatment reversed the expression of p-PERK, ATF4, CHOP, GRP78, cleaved caspase 3 and bax induced by the glaucomatous model. Meanwhile, the CCT020312 reversed the valdecoxib's anti-apoptosis effect by activating PERK-ATF4-CHOP pathway-mediated endoplasmic reticulum (ER) stress. These findings suggest that valdecoxib protects against glaucomatous injury by inhibiting ER stress-induced apoptosis via the inhibition of the PERK-ATF4-CHOP pathway.
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Affiliation(s)
- Zhaolin Gao
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha 410008, China
| | - Min Li
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
| | - Fei Yao
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha 410008, China
| | - Xiaobo Xia
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha 410008, China
| | - Tianqi Duan
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
| | - Jingzhuo Meng
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
| | - Yanxia Huang
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
| | - Ye He
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha 410008, China
| | - Adonira Saro
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
| | - Jufang Huang
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha 410008, China
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The Pathogenesis and Therapeutic Approaches of Diabetic Neuropathy in the Retina. Int J Mol Sci 2021; 22:ijms22169050. [PMID: 34445756 PMCID: PMC8396448 DOI: 10.3390/ijms22169050] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/19/2021] [Accepted: 08/19/2021] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy is a major retinal disease and a leading cause of blindness in the world. Diabetic retinopathy is a neurovascular disease that is associated with disturbances of the interdependent relationship of cells composed of the neurovascular units, i.e., neurons, glial cells, and vascular cells. An impairment of these neurovascular units causes both neuronal and vascular abnormalities in diabetic retinopathy. More specifically, neuronal abnormalities including neuronal cell death and axon degeneration are irreversible changes that are directly related to the vision reduction in diabetic patients. Thus, establishment of neuroprotective and regenerative therapies for diabetic neuropathy in the retina is an emergent task for preventing the blindness of patients with diabetic retinopathy. This review focuses on the pathogenesis of the neuronal abnormalities in diabetic retina including glial abnormalities, neuronal cell death, and axon degeneration. The possible molecular cell death pathways and intrinsic survival and regenerative pathways are also described. In addition, therapeutic approaches for diabetic neuropathy in the retina both in vitro and in vivo are presented. This review should be helpful for providing clues to overcome the barriers for establishing neuroprotection and regeneration of diabetic neuropathy in the retina.
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Abbasi M, Gupta VK, Chitranshi N, Gupta V, Ranjbaran R, Rajput R, Pushpitha K, KB D, You Y, Salekdeh GH, Parton RG, Mirzaei M, Graham SL. Inner retinal injury in experimental glaucoma is prevented upon AAV mediated Shp2 silencing in a caveolin dependent manner. Am J Cancer Res 2021; 11:6154-6172. [PMID: 33995651 PMCID: PMC8120201 DOI: 10.7150/thno.55472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/20/2021] [Indexed: 12/16/2022] Open
Abstract
SH2 domain containing tyrosine phosphatase 2 (Shp2; PTPN11) regulates several intracellular pathways downstream of multiple growth factor receptors. Our studies implicate that Shp2 interacts with Caveolin-1 (Cav-1) protein in retinal ganglion cells (RGCs) and negatively regulates BDNF/TrkB signaling. This study aimed to investigate the mechanisms underlying the protective effects of shp2 silencing in the RGCs in glaucomatous conditions. Methods: Shp2 was silenced in the Cav-1 deficient mice and the age matched wildtype littermates using adeno-associated viral (AAV) constructs. Shp2 expression modulation was performed in an acute and a chronic mouse model of experimental glaucoma. AAV2 expressing Shp2 eGFP-shRNA under a strong synthetic CAG promoter was administered intravitreally in the animals' eyes. The contralateral eye received AAV-eGFP-scramble-shRNA as control. Animals with Shp2 downregulation were subjected to either microbead injections or acute ocular hypertension experimental paradigm. Changes in inner retinal function were evaluated by measuring positive scotopic threshold response (pSTR) while structural and biochemical alterations were evaluated through H&E staining, western blotting and immunohistochemical analysis of the retinal tissues. Results: A greater loss of pSTR amplitudes was observed in the WT mice compared to Cav-1-/- retinas in both the models. Silencing of Shp2 phosphatase imparted protection against inner retinal function loss in chronic glaucoma model in WT mice. The functional rescue also translated to structural preservation of ganglion cell layer in the chronic glaucoma condition in WT mice which was not evident in Cav-1-/- mice retinas. Conclusions: This study indicates that protective effects of Shp2 ablation under chronic experimental glaucoma conditions are dependent on Cav-1 in the retina, suggesting in vivo interactions between the two proteins.
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Oshitari T. Understanding intrinsic survival and regenerative pathways through in vivo and in vitro studies: implications for optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2021. [DOI: 10.1080/17469899.2021.1912595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Japan
- Department of Ophthalmology, International University of Health and Welfare School of Medicine, Narita, Japan
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Gregory-Ksander M, Marshak-Rothstein A. The FasLane to ocular pathology-metalloproteinase cleavage of membrane-bound FasL determines FasL function. J Leukoc Biol 2021; 110:965-977. [PMID: 33565149 DOI: 10.1002/jlb.3ri1220-834r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/26/2022] Open
Abstract
Fas ligand (FasL) is best known for its ability to induce cell death in a wide range of Fas-expressing targets and to limit inflammation in immunoprivileged sites such as the eye. In addition, the ability of FasL to induce a much more extensive list of outcomes is being increasingly explored and accepted. These outcomes include the induction of proinflammatory cytokine production, T cell activation, and cell motility. However, the distinct and opposing functions of membrane-associated FasL (mFasL) and the C-terminal soluble FasL fragment (sFasL) released by metalloproteinase cleavage is less well documented and understood. Both mFasL and sFasL can form trimers that engage the trimeric Fas receptor, but only mFasL can form a multimeric complex in lipid rafts to trigger apoptosis and inflammation. By contrast, a number of reports have now documented the anti-apoptotic and anti-inflammatory activity of sFasL, pointing to a critical regulatory function of the soluble molecule. The immunomodulatory activity of FasL is particularly evident in ocular pathology where elimination of the metalloproteinase cleavage site and the ensuing increased expression of mFasL can severely exacerbate the extent of inflammation and cell death. By contrast, both homeostatic and increased expression of sFasL can limit inflammation and cell death. The mechanism(s) responsible for the protective activity of sFasL are discussed but remain controversial. Nevertheless, it will be important to consider therapeutic applications of sFasL for the treatment of ocular diseases such as glaucoma.
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Affiliation(s)
- Meredith Gregory-Ksander
- Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Ann Marshak-Rothstein
- Department of Medicine/Rheumatology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Krishnan A, Kocab AJ, Zacks DN, Marshak-Rothstein A, Gregory-Ksander M. A small peptide antagonist of the Fas receptor inhibits neuroinflammation and prevents axon degeneration and retinal ganglion cell death in an inducible mouse model of glaucoma. J Neuroinflammation 2019; 16:184. [PMID: 31570110 PMCID: PMC6767653 DOI: 10.1186/s12974-019-1576-3] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/29/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Glaucoma is a complex, multifactorial disease where apoptosis, microglia activation, and inflammation have been linked to the death of retinal ganglion cells (RGCs) and axon degeneration. We demonstrated previously that FasL-Fas signaling was required for axon degeneration and death of RGCs in chronic and inducible mouse models of glaucoma and that Fas activation triggered RGC apoptosis, glial activation, and inflammation. Here, we investigated whether targeting the Fas receptor with a small peptide antagonist, ONL1204, has anti-inflammatory and neuroprotective effects in a microbead-induced mouse model of glaucoma. METHODS Intracameral injection of microbeads was used to elevate intraocular pressure (IOP) in Fas-deficient (Faslpr) mice and WT C57BL/6J mice that received an intravitreal injection of the Fas inhibitor, ONL1204 (2 μg/1 μl) (or vehicle only), on day 0 or day 7 after microbead injection. The IOP was monitored by rebound tonometry, and at 28 days post-microbead injection, Brn3a-stained RGCs and paraphenylenediamine (PPD)-stained axons were analyzed. The effects of ONL1204 on retinal microglia activation and the expression of inflammatory genes were analyzed by immunostaining of retinal flatmounts and quantitative PCR (qPCR). RESULTS Rebound tonometry showed equivalent elevation of IOP in all groups of microbead-injected mice. At 28 days post-microbead injection, the RGC and axon counts from microbead-injected Faslpr mice were equivalent to saline-injected (no IOP elevation) controls. Treatment with ONL1204 also significantly reduced RGC death and loss of axons in microbead-injected WT mice when compared to vehicle-treated controls, even when administered after IOP elevation. Confocal analysis of Iba1-stained retinal flatmounts and qPCR demonstrated that ONL1204 also abrogated microglia activation and inhibited the induction of multiple genes implicated in glaucoma, including cytokines and chemokines (GFAP, Caspase-8, TNFα, IL-1β, IL-6, IL-18, MIP-1α, MIP-1β, MIP-2, MCPI, and IP10), components of the complement cascade (C3, C1Q), Toll-like receptor pathway (TLR4), and inflammasome pathway (NLRP3). CONCLUSIONS These results serve as proof-of-principal that the small peptide inhibitor of the Fas receptor, ONL1204, can provide robust neuroprotection in an inducible mouse model of glaucoma, even when administered after IOP elevation. Moreover, Fas signaling contributes to the pathogenesis of glaucoma through activation of both apoptotic and inflammatory pathways.
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Affiliation(s)
- Anitha Krishnan
- Department of Ophthalmology, The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, USA
| | | | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Ann Marshak-Rothstein
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Meredith Gregory-Ksander
- Department of Ophthalmology, The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, USA.
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Park HYL, Kim SW, Kim JH, Park CK. Increased levels of synaptic proteins involved in synaptic plasticity after chronic intraocular pressure elevation and modulation by brain-derived neurotrophic factor in a glaucoma animal model. Dis Model Mech 2019; 12:dmm.037184. [PMID: 31142572 PMCID: PMC6602315 DOI: 10.1242/dmm.037184] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 05/08/2019] [Indexed: 12/30/2022] Open
Abstract
The dendrites of retinal ganglion cells (RGCs) synapse with the axon terminals of bipolar cells in the inner plexiform layer (IPL). Changes in the RGC dendrites and synapses between the bipolar cells in the inner retinal layer may critically alter the function of RGCs in glaucoma. The present study attempted to discover changes in the synapse using brain-derived neurotrophic factor (BDNF) after glaucoma induction by chronic intraocular pressure elevation in a rat model. Immunohistochemical staining revealed that the BDNF-injected group had a significant increase in the level of synaptophysin, which is a presynaptic vesicle protein, in the innermost IPL compared with the phosphate-buffered saline (PBS)-injected group. SMI-32, which is a marker of RGCs, was colocalized with synaptophysin in RGC dendrites, and this colocalization significantly increased in the BDNF-injected group. After the induction of glaucoma, the BDNF-injected group exhibited increases in the total number of ribbon synapses, as seen using electron microscopy. Expression of calcium/calmodulin-dependent protein kinase II (CaMKII), cAMP-response element binding protein (CREB) and F-actin, which are key molecules involved in synaptic changes were upregulated after BDNF injection. These initial findings show the capability of BDNF to induce beneficial synaptic changes in glaucoma. Summary: Application of BDNF increased the expression of synaptic vesicle proteins in the inner retina via the p-Akt, CaMKII and CREB pathways, increasing F-actin in RGC dendrites.
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Affiliation(s)
- Hae-Young Lopilly Park
- Department of Ophthalmology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Si Won Kim
- Department of Ophthalmology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Jie Hyun Kim
- Department of Ophthalmology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Chan Kee Park
- Department of Ophthalmology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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11
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Pérez de Lara MJ, Avilés-Trigueros M, Guzmán-Aránguez A, Valiente-Soriano FJ, de la Villa P, Vidal-Sanz M, Pintor J. Potential role of P2X7 receptor in neurodegenerative processes in a murine model of glaucoma. Brain Res Bull 2019; 150:61-74. [PMID: 31102752 DOI: 10.1016/j.brainresbull.2019.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 04/23/2019] [Accepted: 05/10/2019] [Indexed: 12/20/2022]
Abstract
Glaucoma is a common cause of visual impairment and blindness, characterized by retinal ganglion cell (RGC) death. The mechanisms that trigger the development of glaucoma remain unknown and have gained significant relevance in the study of this neurodegenerative disease. P2X7 purinergic receptors (P2X7R) could be involved in the regulation of the synaptic transmission and neuronal death in the retina through different pathways. The aim of this study was to characterize the molecular signals underlying glaucomatous retinal injury. The time-course of functional, morphological, and molecular changes in the glaucomatous retina of the DBA/2J mice were investigated. The expression and localization of P2X7R was analysed in relation with retinal markers. Caspase-3, JNK, and p38 were evaluated in control and glaucomatous mice by immunohistochemical and western-blot analysis. Furthermore, electroretinogram recordings (ERG) were performed to assess inner retina dysfunction. Glaucomatous mice exhibited changes in P2X7R expression as long as the pathology progressed. There was P2X7R overexpression in RGCs, the primary injured neurons, which correlated with the loss of function through ERG measurements. All analyzed MAPK and caspase-3 proteins were upregulated in the DBA/2J retinas suggesting a pro-apoptotic cell death. The increase in P2X7Rs presence may contribute, together with other factors, to the changes in retinal functionality and the concomitant death of RGCs. These findings provide evidence of possible intracellular pathways responsible for apoptosis regulation during glaucomatous degeneration.
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Affiliation(s)
- María J Pérez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
| | - Marcelino Avilés-Trigueros
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain
| | - Ana Guzmán-Aránguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
| | - F Javier Valiente-Soriano
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain
| | - Pedro de la Villa
- Systems Biology Department, Faculty of Medicine, University of Alcalá, Alcalá de Henares, Madrid, Spain
| | - Manuel Vidal-Sanz
- Laboratory of Experimental Ophthalmology, Dept. of Ophthalmology, Faculty of Medicine, University of Murcia and Murcia Institute of Bio-Health Research (IMIB), E-30120, El Palmar, Murcia, Spain.
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, E-28037, Madrid, Spain
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12
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Stifter J, Ulbrich F, Goebel U, Böhringer D, Lagrèze WA, Biermann J. Neuroprotection and neuroregeneration of retinal ganglion cells after intravitreal carbon monoxide release. PLoS One 2017; 12:e0188444. [PMID: 29176876 PMCID: PMC5703485 DOI: 10.1371/journal.pone.0188444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 11/07/2017] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Retinal ischemia induces apoptosis leading to neurodegeneration and vision impairment. Carbon monoxide (CO) in gaseous form showed cell-protective and anti-inflammatory effects after retinal ischemia-reperfusion-injury (IRI). These effects were also demonstrated for the intravenously administered CO-releasing molecule (CORM) ALF-186. This article summarizes the results of intravitreally released CO to assess its suitability as a neuroprotective and neuroregenerative agent. METHODS Water-soluble CORM ALF-186 (25 μg), PBS, or inactivated ALF (iALF) (all 5 μl) were intravitreally applied into the left eyes of rats directly after retinal IRI for 1 h. Their right eyes remained unaffected and were used for comparison. Retinal tissue was harvested 24 h after intervention to analyze mRNA or protein expression of Caspase-3, pERK1/2, p38, HSP70/90, NF-kappaB, AIF-1 (allograft inflammatory factor), TNF-α, and GAP-43. Densities of fluorogold-prelabeled retinal ganglion cells (RGC) were examined in flat-mounted retinae seven days after IRI and were expressed as mean/mm2. The ability of RGC to regenerate their axon was evaluated two and seven days after IRI using retinal explants in laminin-1-coated cultures. Immunohistochemistry was used to analyze the different cell types growing out of the retinal explants. RESULTS Compared to the RGC-density in the contralateral right eyes (2804±214 RGC/mm2; data are mean±SD), IRI+PBS injection resulted in a remarkable loss of RGC (1554±159 RGC/mm2), p<0.001. Intravitreally injected ALF-186 immediately after IRI provided RGC protection and reduced the extent of RGC-damage (IRI+PBS 1554±159 vs. IRI+ALF 2179±286, p<0.001). ALF-186 increased the IRI-mediated phosphorylation of MAP-kinase p38. Anti-apoptotic and anti-inflammatory effects were detectable as Caspase-3, NF-kappaB, TNF-α, and AIF-1 expression were significantly reduced after IRI+ALF in comparison to IRI+PBS or IRI+iALF. Gap-43 expression was significantly increased after IRI+ALF. iALF showed effects similar to PBS. The intrinsic regenerative potential of RGC-axons was induced to nearly identical levels after IRI and ALF or iALF-treatment under growth-permissive conditions, although RGC viability differed significantly in both groups. Intravitreal CO further increased the IRI-induced migration of GFAP-positive cells out of retinal explants and their transdifferentiation, which was detected by re-expression of beta-III tubulin and nestin. CONCLUSION Intravitreal CORM ALF-186 protected RGC after IRI and stimulated their axons to regenerate in vitro. ALF conveyed anti-apoptotic, anti-inflammatory, and growth-associated signaling after IRI. CO's role in neuroregeneration and its effect on retinal glial cells needs further investigation.
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Affiliation(s)
- Julia Stifter
- Eye Center, Medical Center—University of Freiburg, Killianstrasse 5, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Felix Ulbrich
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Anesthesiology and Intensive Care, Medical Center—University of Freiburg, Hugstetter Strasse 55, Freiburg, Germany
| | - Ulrich Goebel
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Anesthesiology and Intensive Care, Medical Center—University of Freiburg, Hugstetter Strasse 55, Freiburg, Germany
| | - Daniel Böhringer
- Eye Center, Medical Center—University of Freiburg, Killianstrasse 5, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Wolf Alexander Lagrèze
- Eye Center, Medical Center—University of Freiburg, Killianstrasse 5, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Biermann
- Eye Center, Medical Center—University of Freiburg, Killianstrasse 5, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Ophthalmology, University of Muenster Medical Center, Domagkstrasse 15, Muenster, Germany
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Thomas CN, Berry M, Logan A, Blanch RJ, Ahmed Z. Caspases in retinal ganglion cell death and axon regeneration. Cell Death Discov 2017; 3:17032. [PMID: 29675270 PMCID: PMC5903394 DOI: 10.1038/cddiscovery.2017.32] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 03/31/2017] [Accepted: 04/23/2017] [Indexed: 02/07/2023] Open
Abstract
Retinal ganglion cells (RGC) are terminally differentiated CNS neurons that possess limited endogenous regenerative capacity after injury and thus RGC death causes permanent visual loss. RGC die by caspase-dependent mechanisms, including apoptosis, during development, after ocular injury and in progressive degenerative diseases of the eye and optic nerve, such as glaucoma, anterior ischemic optic neuropathy, diabetic retinopathy and multiple sclerosis. Inhibition of caspases through genetic or pharmacological approaches can arrest the apoptotic cascade and protect a proportion of RGC. Novel findings have also highlighted a pyroptotic role of inflammatory caspases in RGC death. In this review, we discuss the molecular signalling mechanisms of apoptotic and inflammatory caspase responses in RGC specifically, their involvement in RGC degeneration and explore their potential as therapeutic targets.
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Affiliation(s)
- Chloe N Thomas
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Martin Berry
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Ann Logan
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Richard J Blanch
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham, UK
| | - Zubair Ahmed
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
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Epigenetics and Signaling Pathways in Glaucoma. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5712341. [PMID: 28210622 PMCID: PMC5292191 DOI: 10.1155/2017/5712341] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/28/2016] [Accepted: 12/13/2016] [Indexed: 12/22/2022]
Abstract
Glaucoma is the most common cause of irreversible blindness worldwide. This neurodegenerative disease becomes more prevalent with aging, but predisposing genetic and environmental factors also contribute to increased risk. Emerging evidence now suggests that epigenetics may also be involved, which provides potential new therapeutic targets. These three factors work through several pathways, including TGF-β, MAP kinase, Rho kinase, BDNF, JNK, PI-3/Akt, PTEN, Bcl-2, Caspase, and Calcium-Calpain signaling. Together, these pathways result in the upregulation of proapoptotic gene expression, the downregulation of neuroprotective and prosurvival factors, and the generation of fibrosis at the trabecular meshwork, which may block aqueous humor drainage. Novel therapeutic agents targeting these pathway members have shown preliminary success in animal models and even human trials, demonstrating that they may eventually be used to preserve retinal neurons and vision.
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15
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Nucci C, Russo R, Martucci A, Giannini C, Garaci F, Floris R, Bagetta G, Morrone LA. New strategies for neuroprotection in glaucoma, a disease that affects the central nervous system. Eur J Pharmacol 2016; 787:119-26. [DOI: 10.1016/j.ejphar.2016.04.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 01/30/2023]
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16
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Retinal Cell Degeneration in Animal Models. Int J Mol Sci 2016; 17:ijms17010110. [PMID: 26784179 PMCID: PMC4730351 DOI: 10.3390/ijms17010110] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 12/25/2015] [Accepted: 01/08/2016] [Indexed: 01/01/2023] Open
Abstract
The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl2-induced), autoimmune (experimental autoimmune encephalomyelitis), mechanical stress (optic nerve crush-induced, light-induced) and ischemia (transient retinal ischemia-induced). The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage.
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17
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Levkovitch-Verbin H. Retinal ganglion cell apoptotic pathway in glaucoma: Initiating and downstream mechanisms. PROGRESS IN BRAIN RESEARCH 2015; 220:37-57. [PMID: 26497784 DOI: 10.1016/bs.pbr.2015.05.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Apoptosis of retinal ganglion cells (RGCs) in glaucoma causes progressive visual field loss, making it the primary cause of irreversible blindness worldwide. Elevated intraocular pressure and aging, the main risk factors for glaucoma, accelerate RGC apoptosis. Numerous pathways and mechanisms were found to be involved in RGC death in glaucoma. Neurotrophic factors deprivation is an early event. Oxidative stress, mitochondrial dysfunction, inflammation, glial cell dysfunction, and activation of apoptotic pathways and prosurvival pathways play a significant role in RGC death in glaucoma. The most important among the involved pathways are the MAP-kinase pathway, PI-3 kinase/Akt pathway, Bcl-2 family, caspase family, and IAP family.
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Affiliation(s)
- Hani Levkovitch-Verbin
- Glaucoma Service, Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Hashomer, Israel.
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18
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Caspase-7: a critical mediator of optic nerve injury-induced retinal ganglion cell death. Mol Neurodegener 2015; 10:40. [PMID: 26306916 PMCID: PMC4550044 DOI: 10.1186/s13024-015-0039-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/19/2015] [Indexed: 12/18/2022] Open
Abstract
Background Axonal injury of the optic nerve (ON) is involved in various ocular diseases, such as glaucoma and traumatic optic neuropathy, which leads to apoptotic death of retinal ganglion cells (RGCs) and loss of vision. Caspases have been implicated in RGC pathogenesis. However, the role of caspase-7, a functionally unique caspase, in ON injury and RGC apoptosis has not been reported previously. The purpose of this study is to evaluate the role of caspase-7 in ON injury-induced RGC apoptosis. Results C57BL/6 (wildtype, WT) and caspase-7 knockout (Casp7−/−) mice were used. We show that ON crush activated caspase-7 and calpain-1, an upstream activator of caspase-7, in mouse RGCs, as well as hydrolysis of kinectin and co-chaperone P23, specific substrates of caspase-7. ON crush caused a progressive loss of RGCs to 28 days after injury. Knockout of caspase-7 partially and significantly protected against the ON injury-induced RGC loss; RGC density at 28 days post ON crush in Casp7−/− mice was approximately twice of that in WT ON injured retinas. Consistent with changes in RGC counts, spectral-domain optical coherence tomography analysis revealed that ON crush significantly reduced the in vivo thickness of the ganglion cell complex layer (including ganglion cell layer, nerve fiber layer, and inner plexiform layer) in the retina. The ON crush-induced thinning of retinal layer was significantly ameliorated in Casp7−/− mice when compared to WT mice. Moreover, electroretinography analysis demonstrated a decline in the positive component of scotopic threshold response amplitude in ON crushed eyes of the WT mice, whereas this RGC functional response was significantly higher in Casp7−/− mice at 28 days post injury. Conclusion Altogether, our findings indicate that caspase-7 plays a critical role in ON injury-induced RGC death, and inhibition of caspase-7 activity may be a novel therapeutic strategy for glaucoma and other neurodegenerative diseases of the retina. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0039-2) contains supplementary material, which is available to authorized users.
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19
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Gidday JM, Zhang L, Chiang CW, Zhu Y. Enhanced Retinal Ganglion Cell Survival in Glaucoma by Hypoxic Postconditioning After Disease Onset. Neurotherapeutics 2015; 12:502-14. [PMID: 25549850 PMCID: PMC4404439 DOI: 10.1007/s13311-014-0330-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The neuroprotective efficacy of adaptive epigenetics, wherein beneficial gene expression changes are induced by nonharmful "conditioning" stimuli, is now well established in several acute, preclinical central nervous system injury models. Recently, in a mouse model of glaucoma, we demonstrated retinal ganglion cell (RGC) protection by repetitively "preconditioning" with hypoxia prior to disease onset, indicating an epigenetic approach may also yield benefits in chronic neurodegenerative disease. Herein, we determined whether presenting the repetitive hypoxic stimulus after disease initiation [repetitive hypoxic "postconditioning" (RH-Post)] could afford similar functional and morphologic protection against glaucomatous RGC injury. Chronic elevations in intraocular pressure (IOP) were induced unilaterally in adult male C57BL/6 mice by episcleral vein ligation. Mice were randomized to an RH-Post [1 h of systemic hypoxia (11% oxygen) every other day, starting 4 days after IOP elevation] or an untreated control group. After 3 weeks of experimental glaucoma, the 21-27% reduction and 5-25% prolongation in flash visual-evoked potential amplitudes and latencies, respectively, and the 30% impairment in visual acuity were robustly improved in RH-Post-treated mice, as was the 17% loss in RGC soma number and 20% reduction in axon integrity. These protective effects were observed without RH-Post affecting IOP. The present findings demonstrate that functional and morphologic protection of RGCs can be realized by stimulating epigenetic responses during the early stages of disease, and thus constitute a new conceptual approach to glaucoma therapeutics.
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Affiliation(s)
- Jeffrey M Gidday
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, 63110, USA,
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20
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Wei T, Kang Q, Ma B, Gao S, Li X, Liu Y. Activation of autophagy and paraptosis in retinal ganglion cells after retinal ischemia and reperfusion injury in rats. Exp Ther Med 2014; 9:476-482. [PMID: 25574219 PMCID: PMC4280957 DOI: 10.3892/etm.2014.2084] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 11/04/2014] [Indexed: 12/14/2022] Open
Abstract
Glaucoma is a neurodegenerative disease characterized by elevated intraocular pressure (IOP), which causes retinal ischemia and progressive neuronal death. Retinal ischemia/reperfusion (RIR) injury is a common clinical condition representing the main cause of irreversible visual field defects in humans. The aim of this study was to investigate whether non-apoptotic forms of programmed cell death (PCD) have an effect on RIR injury in an experimental model that replicates features of acute hypertensive glaucoma and to explore the possible underlying mechanisms. The activation of autophagy was investigated in retinal ganglion cells (RGCs) following RIR in comparison with a control group, using immunofluorescence against microtubule-associated protein 1 light chain 3 (LC3). RIR injury increased LC3 expression in the cytoplasm of RGCs in the ganglion cell layer (GCL) 6 h after the insult, and the increased expression was sustained throughout the experimental period. Following RIR insult, the number of neurons in the GCL significantly decreased. Ultra-structural analyses showed that double- or multiple-membrane autophagosomes were markedly accumulated in the cytoplasm of RGCs following IOP elevation. Since there are no known markers for paraptosis, its identification was based on morphological criteria. Electron microscopy (EM) analysis revealed severe structural alterations associated with cytoplasmatic vacuolization within the 6 h after RIR injury and RGC death. EM also revealed that vacuoles were derived predominantly from the progressive swelling of the endoplasmic reticulum (ER) and/or mitochondria in RGCs after RIR injury. The results provide novel evidence implicating an important role of autophagy and paraptosis in the pathogenesis of RIR injury. Autophagy and paraptosis take place during developmental cell death in the nervous system as well as in certain cases of neurodegeneration. Therefore, targeting autophagy and paraptosis could have therapeutic potential for the prevention of glaucoma involving RIR injury.
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Affiliation(s)
- Ting Wei
- Department of Ophthalmology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Qianyan Kang
- Department of Ophthalmology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Ma
- Department of Ophthalmology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Shan Gao
- Department of Ophthalmology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Xueying Li
- Department of Ophthalmology, The First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yong Liu
- Institute of Neurobiology, National Key Academic Subject of Physiology, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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21
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Park HYL, Kim JH, Park CK. Alterations of the synapse of the inner retinal layers after chronic intraocular pressure elevation in glaucoma animal model. Mol Brain 2014; 7:53. [PMID: 25116810 PMCID: PMC4237962 DOI: 10.1186/s13041-014-0053-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 07/23/2014] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Dendrites of retinal ganglion cells (RGCs) synapse with axon terminals of bipolar cells in the inner plexiform layer (IPL). Changes in RGC dendrites and synapses between bipolar cells in the inner retinal layer may critically alter the function of RGCs in glaucoma. Recently, synaptic plasticity has been observed in the adult central nervous system, including the outer retinal layers. However, few studies have focused on changes in the synapses between RGCs and bipolar cells in glaucoma. In the present study, we used a rat model of ocular hypertension induced by episcleral vein cauterization to investigate changes in synaptic structure and protein expression in the inner retinal layer at various time points after moderate intraocular pressure (IOP) elevation. RESULTS Synaptophysin, a presynaptic vesicle protein, increased throughout the IPL, outer plexiform layer, and outer nuclear layer after IOP elevation. Increased synaptophysin after IOP elevation was expressed in bipolar cells in the innermost IPL. The RGC marker, SMI-32, co-localized with synaptophysin in RGC dendrites and were significantly increased at 1 week and 4 weeks after IOP elevation. Both synaptophysin and postsynaptic vesicle protein, PSD-95, were increased after IOP elevation by western blot analysis. Ribbon synapses in the IPL were quantified and structurally evaluated in retinal sections by transmission electron microscopy. After IOP elevation the total number of ribbon synapses decreased. There were increases in synapse diameter and synaptic vesicle number and decreases in active zone length and the number of docked vesicles after IOP elevation. CONCLUSIONS Although the total number of synapses decreased as RGCs were lost after IOP elevation, there are attempts to increase synaptic vesicle proteins and immature synapse formation between RGCs and bipolar cells in the inner retinal layers after glaucoma induction.
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Affiliation(s)
| | | | - Chan Kee Park
- Department of Ophthalmology and Visual Science, Seoul St, Mary's Hospital, College of Medicine, The Catholic University of Korea, #505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea.
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Jiang Y, Pagadala J, Miller DD, Steinle JJ. Insulin-like growth factor-1 binding protein 3 (IGFBP-3) promotes recovery from trauma-induced expression of inflammatory and apoptotic factors in retina. Cytokine 2014; 70:115-9. [PMID: 25082650 DOI: 10.1016/j.cyto.2014.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/28/2014] [Accepted: 07/07/2014] [Indexed: 11/28/2022]
Abstract
Ocular trauma affects 20% of Americans in their lifetime and can cause permanent visual system damage. We have used a mouse model of ocular trauma (exposure to an air blast from a paintball gun) to examine pathways that trigger the resulting retinal damage and to develop treatment strategies that might ameliorate the deleterious effects of trauma on retinal tissue. Our previous studies have shown that ocular blast causes an increase in protein levels of inflammatory mediators and apoptotic factors, including tumor necrosis factor alpha (TNFα) and interleukin-1-beta (IL-1β), as well as the apoptotic markers, Bax, cytochrome C, and cleaved caspase 3. Furthermore, topical treatment by eye drop application of a β-adrenergic receptor agonist, Compound 49b, was shown to decrease these inflammation/apoptosis markers and thus ameliorate the effects of blast trauma. We postulate that the protective effect of Compound 49b may be linked to its demonstrated ability to activate the β-adrenergic receptor and in turn trigger production of insulin-like growth factor binding protein 3 (IGFBP-3). In the current study, we tested this hypothesis using mice with minimal IGFBP-3 activity (IGFBP-3 knockdown mouse) vs. wildtype mice. We found that ocular blast alone did not affect IGFBP-3 levels in retinas of wild type or knockdown mice and surprisingly, the lower levels of IGFBP-3 in knockdown animals did not exacerbate the blast-induced increase in protein levels of inflammation/apoptosis markers. Nevertheless, the levels of IGFBP-3 were significantly increased in knockdown mouse retina by treatment with Compound 49b 24h post-trauma and as expected, the increase in IGFBP-3 was linked to a decrease in inflammation/apoptosis markers. We conclude that while lowered IGFBP-3 may not make the retina more vulnerable to blast injury, an increase in IGFBP-3 post-trauma may play an important role in limiting trauma-induced inflammatory and apoptotic pathways leading to retinal damage. Eye drop application of the β-adrenergic receptor agonist, Compound 49b, provides a promising treatment strategy for increasing IGFBP-3 levels to promote recovery from retinal inflammation and apoptosis after ocular blast.
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Affiliation(s)
- Youde Jiang
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Jayaprakash Pagadala
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Duane D Miller
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Jena J Steinle
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, United States; Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN, United States; Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States.
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Su W, Li Z, Jia Y, Zhuo Y. Rapamycin is neuroprotective in a rat chronic hypertensive glaucoma model. PLoS One 2014; 9:e99719. [PMID: 24923557 PMCID: PMC4055719 DOI: 10.1371/journal.pone.0099719] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 05/19/2014] [Indexed: 12/20/2022] Open
Abstract
Glaucoma is a leading cause of irreversible blindness. Injury of retinal ganglion cells (RGCs) accounts for visual impairment of glaucoma. Here, we report rapamycin protects RGCs from death in experimental glaucoma model and the underlying mechanisms. Our results showed that treatment with rapamycin dramatically promote RGCs survival in a rat chronic ocular hypertension model. This protective action appears to be attributable to inhibition of neurotoxic mediators release and/or direct suppression of RGC apoptosis. In support of this mechanism, in vitro, rapamycin significantly inhibits the production of NO, TNF-α in BV2 microglials by modulating NF-κB signaling. In experimental animals, treatment with rapamycin also dramatically inhibited the activation of microglials. In primary RGCs, rapamycin was capable of direct suppression the apoptosis of primary RGCs induced by glutamate. Mechanistically, rapamycin-mediated suppression of RGCs apoptosis is by sparing phosphorylation of Akt at a site critical for maintenance of its survival-promoting activity in cell and animal model. These results demonstrate that rapamycin is neuroprotective in experimental glaucoma, possibly via decreasing neurotoxic releasing and suppressing directly apoptosis of RGCs.
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Affiliation(s)
- Wenru Su
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zuohong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yu Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- * E-mail:
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Wilson AM, Chiodo VA, Boye SL, Brecha NC, Hauswirth WW, Di Polo A. Inhibitor of apoptosis-stimulating protein of p53 (iASPP) is required for neuronal survival after axonal injury. PLoS One 2014; 9:e94175. [PMID: 24714389 PMCID: PMC3979759 DOI: 10.1371/journal.pone.0094175] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/11/2014] [Indexed: 11/18/2022] Open
Abstract
The transcription factor p53 mediates the apoptosis of post-mitotic neurons exposed to a wide range of stress stimuli. The apoptotic activity of p53 is tightly regulated by the apoptosis-stimulating proteins of p53 (ASPP) family members: ASPP1, ASPP2 and iASPP. We previously showed that the pro-apoptotic members ASPP1 and ASPP2 contribute to p53-dependent death of retinal ganglion cells (RGCs). However, the role of the p53 inhibitor iASPP in the central nervous system (CNS) remains to be elucidated. To address this, we asked whether iASPP contributes to the survival of RGCs in an in vivo model of acute optic nerve damage. We demonstrate that iASPP is expressed by injured RGCs and that iASPP phosphorylation at serine residues, which increase iASPP affinity towards p53, is significantly reduced following axotomy. We show that short interference RNA (siRNA)-induced iASPP knockdown exacerbates RGC death, whereas adeno-associated virus (AAV)-mediated iASPP expression promotes RGC survival. Importantly, our data also demonstrate that increasing iASPP expression in RGCs downregulates p53 activity and blocks the expression of pro-apoptotic targets PUMA and Fas/CD95. This study demonstrates a novel role for iASPP in the survival of RGCs, and provides further evidence of the importance of the ASPP family in the regulation of neuronal loss after axonal injury.
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Affiliation(s)
- Ariel M Wilson
- Department of Neuroscience and Groupe de Recherche sur le Système Nerveux Central, University of Montreal Hospital Research Center (CR-CHUM), University of Montreal, Montreal, Quebec, Canada
| | - Vince A Chiodo
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Nicholas C Brecha
- Departments of Neurobiology and Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Adriana Di Polo
- Department of Neuroscience and Groupe de Recherche sur le Système Nerveux Central, University of Montreal Hospital Research Center (CR-CHUM), University of Montreal, Montreal, Quebec, Canada
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25
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Upregulation of CREM-1 relates to retinal ganglion cells apoptosis after light-induced damage in vivo. J Mol Neurosci 2013; 52:331-8. [PMID: 24166353 DOI: 10.1007/s12031-013-0153-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
Abstract
Previous studies have shown activation of cyclic AMP response element-binding protein (CREB) family is involved in the retinal ganglion cells (RGCs) protection. However, the function of cyclic AMP response element modulator-1 (CREM-1), one member of the CREB family, is still with limited acquaintance. To investigate whether CREM-1 is involved in RGCs death, we performed a light-induced retinal damage model in adult rats. Upregulation of CREM-1 was observed in retina after light-induced damage by performing western blot. Immunofluorescent labeling indicated that upregulated CREM-1 was localized mainly in the RGCs. We also investigated co-localization of CREM-1 with active-caspase-3 and TUNEL (apoptotic markers) in the retina after light-induced damage. In addition, the expression patterns of B cell lymphoma/leukemia-2 and Bcl-2 associated X protein were parallel with that of CREM-1. Collectively, we hypothesized upregulation of CREM-1 in the retina was associated with RGCs death after light-induced damage.
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26
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Aslan M, Dogan S, Kucuksayan E. Oxidative stress and potential applications of free radical scavengers in glaucoma. Redox Rep 2013; 18:76-87. [PMID: 23485101 DOI: 10.1179/1351000212y.0000000033] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness in industrialized countries and comprises a group of diseases characterized by progressive optic nerve degeneration. Glaucoma is commonly associated with elevated intraocular pressure due to impaired outflow of aqueous humor resulting from abnormalities within the drainage system of the anterior chamber angle (open-angle glaucoma) or impaired access of aqueous humor to the drainage system (angle-closure glaucoma). Oxidative injury and altered antioxidant defense mechanisms in glaucoma appear to play a role in the pathophysiology of glaucomatous neurodegeneration that is characterized by death of retinal ganglion cells. Oxidative protein modifications occurring in glaucoma serve as immunostimulatory signals and alter neurosupportive and immunoregulatory functions of glial cells. Initiation of the apoptotic cascade observed in glaucomatous retinopathy can involve oxidant mechanisms and different agents have been shown to be neuroprotective. This review focuses on the molecular mechanisms of oxidant injury and summarizes studies that have investigated novel free radical scavengers in the treatment of glaucomatous neurodegeneration.
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Affiliation(s)
- Mutay Aslan
- Akdeniz University Medical School, Antalya, Turkey.
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27
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VEGF-A is necessary and sufficient for retinal neuroprotection in models of experimental glaucoma. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1379-90. [PMID: 23416159 PMCID: PMC3608027 DOI: 10.1016/j.ajpath.2012.12.032] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/19/2012] [Accepted: 12/31/2012] [Indexed: 12/12/2022]
Abstract
Vascular endothelial growth factor A (VEGF-A) is a validated therapeutic target in several angiogenic- and vascular permeability–related pathological conditions, including certain cancers and potentially blinding diseases, such as age-related macular degeneration and diabetic retinopathy. We and others have shown that VEGF-A also plays an important role in neuronal development and neuroprotection, including in the neural retina. Antagonism of VEGF-A function might therefore present a risk to neuronal survival as a significant adverse effect. Herein, we demonstrate that VEGF-A acts directly on retinal ganglion cells (RGCs) to promote survival. VEGF receptor-2 signaling via the phosphoinositide-3-kinase/Akt pathway was required for the survival response in isolated RGCs. These results were confirmed in animal models of staurosporine-induced RGC death and experimental hypertensive glaucoma. Importantly, we observed that VEGF-A blockade significantly exacerbated neuronal cell death in the hypertensive glaucoma model. Our findings highlight the need to better define the risks associated with use of VEGF-A antagonists in the ocular setting.
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28
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Zimering MB, Moritz TE, Donnelly RJ. Anti-neurotrophic effects from autoantibodies in adult diabetes having primary open angle glaucoma or dementia. Front Endocrinol (Lausanne) 2013; 4:58. [PMID: 23720653 PMCID: PMC3654220 DOI: 10.3389/fendo.2013.00058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 05/01/2013] [Indexed: 12/27/2022] Open
Abstract
AIM To test for anti-endothelial and anti-neurotrophic effects from autoantibodies in subsets of diabetes having open-angle glaucoma, dementia, or control subjects. METHODS Protein-A eluates from plasma of 20 diabetic subjects having glaucoma or suspects and 34 age-matched controls were tested for effects on neurite outgrowth in rat pheochromocytoma PC12 cells or endothelial cell survival. The mechanism of the diabetic glaucoma autoantibodies' neurite-inhibitory effect was investigated in co-incubations with the selective Rho kinase inhibitor Y27632 or the sulfated proteoglycan synthesis inhibitor sodium chlorate. Stored protein-A eluates from certain diabetic glaucoma or dementia subjects which contained long-lasting, highly stable cell inhibitory substances were characterized using mass spectrometry and amino acid sequencing. RESULTS Diabetic primary open angle glaucoma (POAG) or suspects (n = 20) or diabetic dementia (n = 3) autoantibodies caused significantly greater mean inhibition of neurite outgrowth in PC12 cells (p < 0.0001) compared to autoantibodies in control diabetic (n = 24) or non-diabetic (n = 10) subjects without glaucoma (p < 0.01). Neurite inhibition by the diabetic glaucoma autoantibodies was completely abolished by 10 μM concentrations of Y27632 (n = 4). It was substantially reduced by 30 mM concentrations of sodium chlorate (n = 4). Peak, long-lasting activity survived storage ×5 years at 0-4°C and was associated with a restricted subtype of Ig kappa light chain. Diabetic glaucoma or dementia autoantibodies (n = 5) caused contraction and process retraction in quiescent cerebral cortical astrocytes effects which were blocked by 5 μM concentrations of Y27632. CONCLUSION These data suggest that autoantibodies in subsets of adult diabetes having POAG (glaucoma suspects) and/or dementia inhibit neurite outgrowth and promote a reactive astrocyte morphology by a mechanism which may involve activation of the RhoA/p160 ROCK signaling pathway.
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Affiliation(s)
- Mark B. Zimering
- Medical Service, New Jersey Health Care System, Department of Veterans AffairsLyons, NJ, USA
- Robert Wood Johnson Medical School, University of Medicine and Dentistry of New JerseyNew Brunswick, NJ, USA
- *Correspondence: Mark B. Zimering, Medical Service 111, Veterans Affairs New Jersey Healthcare System, Lyons, NJ 07939, USA. e-mail:
| | - Thomas E. Moritz
- Cooperative Study Coordinating Center, Hines Veterans HospitalHines, IL, USA
| | - Robert J. Donnelly
- Molecular Resource Facility, University of Medicine and Dentistry of New Jersey, New Jersey Medical SchoolNewark, NJ, USA
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29
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Park HYL, Kim JH, Park CK. Activation of autophagy induces retinal ganglion cell death in a chronic hypertensive glaucoma model. Cell Death Dis 2012; 3:e290. [PMID: 22476098 PMCID: PMC3358006 DOI: 10.1038/cddis.2012.26] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autophagy is reported to have important roles in relation to regulated cell death pathways and neurodegeneration. This study used chronic hypertensive glaucoma rat model to investigate whether the autophagy pathway has a role in the apoptosis of retinal ganglion cells (RGCs) after chronic intraocular pressure (IOP) elevation. Under electron microscopy, autophagosomes were markedly accumulated in the dendrites and cytoplasm of RGCs after IOP elevation. Western blot analysis showed that LC3-II/LC3-I and beclin-1 were upregulated throughout the 8-weeks period after IOP elevation. The pattern of LC3 immunostaining showed autophagy activation in the cytoplasm of RGCs to increase and peak at 4 weeks after IOP elevation. Most of these LC3B-positive RGCs underwent apoptosis by terminal deoxynucleotidyltransferase-mediated biotinylated UTP nick end labeling, and inhibition of autophagy with 3-methyladenine decreased RGC apoptosis. The activated pattern shows that autophagy is initially activated in the dendrites of the RGCs, but, thereafter autophagy is mainly activated in the cytoplasm of RGCs. This may show that autophagy is differently regulated in different compartments of the neuron. This present study showed that autophgy is activated in RGCs and has a role in autophagic cell death after chronic IOP elevation.
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Affiliation(s)
- H Y Lopilly Park
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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30
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Involvement of caspase-6 and caspase-8 in neuronal apoptosis and the regenerative failure of injured retinal ganglion cells. J Neurosci 2011; 31:10494-505. [PMID: 21775595 DOI: 10.1523/jneurosci.0148-11.2011] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
To promote functional recovery after CNS injuries, it is crucial to develop strategies that enhance both neuronal survival and regeneration. Here, we report that caspase-6 is upregulated in injured retinal ganglion cells and that its inhibition promotes both survival and regeneration in these adult CNS neurons. Treatment of rat retinal whole mounts with Z-VEID-FMK, a selective inhibitor of caspase-6, enhanced ganglion cell survival. Moreover, retinal explants treated with this drug extended neurites on myelin. We also show that caspase-6 inhibition resulted in improved ganglion cell survival and robust axonal regeneration following optic nerve injury in adult rats. The effects of Z-VEID-FMK were similar to other caspase inhibitory peptides including Z-LEHD-FMK and Z-VAD-FMK. In searching for downstream effectors for caspase-6, we identified caspase-8, whose expression pattern resembled that of caspase-6 in the injured eye. We then showed that caspase-8 is activated downstream of caspase-6 in the injured adult retina. Furthermore, we investigated the role of caspase-8 in RGC apoptosis and regenerative failure both in vitro and in vivo. We observed that caspase-8 inhibition by Z-IETD-FMK promoted survival and regeneration to an extent similar to that obtained with caspase-6 inhibition. Our results indicate that caspase-6 and caspase-8 are components of a cellular pathway that prevents neuronal survival and regeneration in the adult mammalian CNS.
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31
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Qu J, Wang D, Grosskreutz CL. WITHDRAWN: Reprint of: Mechanisms of retinal ganglion cell injury and defense in glaucoma. Exp Eye Res 2011:S0014-4835(11)00227-2. [PMID: 21819981 DOI: 10.1016/j.exer.2011.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 04/07/2010] [Indexed: 11/30/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.exer.2010.04.002. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Juan Qu
- Department of Ophthalmology, Howe Laboratory of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
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Mali RS, Zhang XM, Chintala SK. A decrease in phosphorylation of cAMP-response element-binding protein (CREBP) promotes retinal degeneration. Exp Eye Res 2011; 92:528-36. [PMID: 21459086 DOI: 10.1016/j.exer.2011.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/15/2011] [Accepted: 03/24/2011] [Indexed: 01/14/2023]
Abstract
Excitotoxicity, induced either by N-Methyl-d-aspartate (NMDA) or kainic acid (KA), promotes irreversible loss of retinal ganglion cells (RGCs). Although the intracellular signaling mechanisms underlying excitotoxic cell death are still unclear, recent studies on the retina indicate that NMDA promotes RGC death by increasing phosphorylation of cyclic AMP (cAMP) response element (CRE)-binding protein (CREBP), while studies on the central nervous system indicate that KA promotes neuronal cell death by decreasing phosphorylation of CREBP, suggesting that CREBP can elicit dual responses depending on the excitotoxic-agent. Interestingly, the role of CREBP in KA-mediated death of RGCs has not been investigated. Therefore, by using an animal model of excitotoxicity, the aim of this study was to investigate whether excitotoxicity induces RGC death by decreasing Ser(133)-CREBP in the retina. Death of RGCs was induced in CD-1 mice by an intravitreal injection of 20 nmoles of kainic acid (KA). Decrease in CREBP levels was determined by immunohistochemistry, western blot analysis, and electrophoretic mobility gel shift assays (EMSAs). Immunohistochemical analysis indicated that CREBP was constitutively expressed in the nuclei of cells both in the ganglion cell layer (GCL) and in the inner nuclear layer (INL) of CD-1 mice. At 6 h after KA injection, nuclear localization of Ser(133)-CREBP was decreased in the GCL. At 24 h after KA injection, Ser(133)-CREBP was decreased further in GCL and the INL, and a decrease in Ser(133)-CREBP correlated with apoptotic death of RGCs and amacrine cells. Western blot analysis indicated that KA decreased Ser(133)-CREBP levels in retinal protein extracts. EMSA assays indicated that KA also reduced the binding of Ser(133)-CREBP to CRE consensus oligonucleotides. In contrast, intravitreal injection of CNQX, a non-NMDA glutamate receptor antagonist, restored the KA-induced decrease in Ser(133)-CREBP both in the GCL and INL, and inhibited loss of RGCs and amacrine cells. These results, for the first time, suggest that KA promotes retinal degeneration by reducing phosphorylation of Ser(133)-CREBP in the retina.
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Affiliation(s)
- Raghuveer S Mali
- Eye Research Institute, Oakland University, Rochester, MI 48309, USA
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33
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Park HYL, Kim JH, Lee DE, Lee JH, Park CK. Changes of the Retina and Intrinsic Survival Signals in a Rat Model of Glaucoma following Brinzolamide and Travoprost Treatments. Ophthalmic Res 2011; 46:208-17. [DOI: 10.1159/000324779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 02/02/2011] [Indexed: 01/28/2023]
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Qu J, Wang D, Grosskreutz CL. Mechanisms of retinal ganglion cell injury and defense in glaucoma. Exp Eye Res 2010; 91:48-53. [PMID: 20394744 DOI: 10.1016/j.exer.2010.04.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 03/23/2010] [Accepted: 04/07/2010] [Indexed: 12/22/2022]
Abstract
Glaucoma is a disease in which retinal ganglion cells (RGCs) die leading ultimately to blindness. Over the past decade and a half, information has begun to emerge regarding specific molecular responses of the retina to conditions of elevated intraocular pressure (IOP). It is now clear that the state of the RGC in glaucoma depends on a balance of pro-survival and pro-death pathways in the retina and details of these responses are still being worked out. In this review, we will discuss the evidence supporting the involvement of specific apoptotic cascades as well as the insults that trigger RGC apoptosis. In addition, we will present evidence supporting the existence of endogenous protective mechanisms as well as exogenous neuroprotective strategies.
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Affiliation(s)
- Juan Qu
- Department of Ophthalmology, Howe Laboratory of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
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35
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Vidal L, Díaz F, Villena A, Moreno M, Campos JG, Pérez de Vargas I. Reaction of Müller cells in an experimental rat model of increased intraocular pressure following timolol, latanoprost and brimonidine. Brain Res Bull 2010; 82:18-24. [PMID: 20206241 DOI: 10.1016/j.brainresbull.2010.02.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 02/19/2010] [Accepted: 02/23/2010] [Indexed: 11/30/2022]
Abstract
The aim of this study was to evaluate the reaction of Müller cells in an experimental rat model of intraocular pressure (IOP) and their response to treatment with ocular hypotensive drugs. Episcleral vein cauterization in unilateral eyes of Wistar rats was performed to produce elevated IOP. The animals were divided into five groups: control, experimental, and experimental treated with timolol, latanoprost or brimonidine. Histological sections of retina were studied by immunochemistry with antibodies to glial fibrillary acidic protein (GFAP), and the percentage of labeled area was measured to evaluate the degree of reactive gliosis. In the experimental group, the Müller cells showed hypertrophy and a significant increase in GFAP (4.39+/-0.32%) in relation to retinas of the control group (2.05+/-0.14%). Gliosis was detected in all three treated groups, with a varying increase in GFAP intensity. The timolol-treated group showed the most intense and persistent glial reactivity after 3 months of treatment (13.89+/-0.63%). Treatment with brimonidine, however, resulted in a decrease in the level of GFAP immunoreactivity (8.37+/-0.4%). The group treated with latanoprost showed the lowest glial reactivity (4.8+/-0.36%). Given that all three drugs are effective hypotensive agents, their neuroprotective effect could be related with other factors, such as gliosis, which, over long periods may have noxious effects on the neurons. Thus, hypotensives like brimonidine, and specially latanoprost, may afford greater neuroprotection to the ganglion cells by attenuating the retinal glial reaction.
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Affiliation(s)
- Lourdes Vidal
- Department of Histology and Histopathology, School of Medicine, University of Malaga, Boulevard Louis Pasteur 32, 29071 Malaga, Spain.
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36
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Retinal ganglion cell death induced by endoplasmic reticulum stress in a chronic glaucoma model. Brain Res 2010; 1308:158-66. [DOI: 10.1016/j.brainres.2009.10.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/09/2009] [Accepted: 10/09/2009] [Indexed: 12/31/2022]
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37
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Sanders EJ, Baudet ML, Parker E, Harvey S. Signaling mechanisms mediating local GH action in the neural retina of the chick embryo. Gen Comp Endocrinol 2009; 163:63-9. [PMID: 19344664 DOI: 10.1016/j.ygcen.2009.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 12/16/2008] [Accepted: 01/13/2009] [Indexed: 12/25/2022]
Abstract
Growth hormone (GH) is found in the retina and vitreous of the chick embryo, where it appears to act as a growth and differentiation factor, having neuroprotective effects on retinal ganglion cells (RGCs). Here, we review the molecular mechanisms of the anti-apoptotic effect of GH in chick RGCs. GH treatment of RGCs reduces Akt levels, while raising Akt-phos levels, consistent with a role for Akt signaling pathways in the GH neuroprotective action. The induction of apoptosis by immunoneutralization with GH antiserum is accompanied by an increase in caspase-3 and caspase-9 activation, and also PARP-1 cleavage. Calpain activation also appears to be a major caspase-independent pathway to PARP-1 cleavage and apoptosis in these cells, supporting the view that caspase and calpain inhibitors are major neuroprotective agents for RGCs, and that pathways that activate both caspases and calpains are important for the anti-apoptotic actions of GH in these cells. These pathways involve the activation of cytosolic tyrosine kinases (Trks) and extracellular-signal-related kinases (ERKs). Occupation of the GH receptor by GH involves downstream intracellular Trk pathways. The Akt and Trk pathways appear to converge on the activation of cAMP response element binding protein (CREB), which is able to initiate transcription of pro- or anti-apoptotic genes. These results indicate that the action of GH in the neuroprotection of embryonic RGCs involves pathways common to with other neurotrophins, and that GH can be considered to be a growth and differentiation factor in the development of the embryonic retina. We have also investigated the relationship between the overlapping anti-apoptotic effects of GH and insulin-like growth factor-1 (IGF-1), two functionally closely related factors. We find that simultaneous immunoneutralization of GH and IGF-1 does not increase the level of apoptosis in the cultures above that achieved by immunoneutralization of GH alone. We therefore conclude that the neuroprotective actions of GH in the developing retina are likely mediated in large part through the action of IGF-1.
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Affiliation(s)
- Esmond J Sanders
- Department of Physiology, University of Alberta, Edmonton, Alta., Canada
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38
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Guo Y, Johnson E, Cepurna W, Jia L, Dyck J, Morrison JC. Does elevated intraocular pressure reduce retinal TRKB-mediated survival signaling in experimental glaucoma? Exp Eye Res 2009; 89:921-33. [PMID: 19682984 DOI: 10.1016/j.exer.2009.08.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 06/16/2009] [Accepted: 08/02/2009] [Indexed: 12/11/2022]
Abstract
Reduced retrograde transport of neurotrophins (NT) and their receptors has been hypothesized to contribute directly to retinal ganglion cell (RGC) loss in glaucoma. However, strategies of supplementing NT and NT receptors have failed to avert ultimate RGC death in experimental glaucoma. This study examines the response of major components of the NT system and their interacting proteins in a rat glaucoma model. Unilateral chronic intraocular pressure (IOP) elevation was produced by episcleral vein injection of hypertonic saline (N = 99). Retinas were collected and grouped by extent of optic nerve injury. Quantitative reverse transcription PCR, western blot analysis and immunohistochemistry were used to determine mRNA and protein levels and protein localization. Out of three RGC-specific Brn3 proteins (Brn3a, b, and c), only Brn3a was significantly downregulated at the message level to 35 +/- 4% of fellow values with the severest nerve injury. With IOP elevation, no significant alterations were found in retinal mRNA levels for BDNF, NGF, NT-4/5 or NT-3. The abundance of mature retinal BDNF protein was not significantly affected by elevated IOP, while proBDNF protein decreased linearly with increasing injury grade (r(2) = 0.50). In retinas with the severest nerve injury, TrkB and TrkC receptor mRNA levels significantly declined to 67 +/- 9% and 44 +/- 5% of fellow values, respectively. However, the levels of TRKB protein and its phosphorylated form were unchanged. Message level for p75(NTR) was linearly upregulated up to 219 +/- 26% with increasing injury (r(2) = 0.46), but no alteration was detected at protein level. The mRNA expression of p75(NTR) apoptosis adaptor proteins NADE, NRIF, and Lingo1 were significantly downregulated in retinas with the greatest nerve injury. A positive correlation was found between injury extent and message levels for Jun (r(2) = 0.23) as well as Junb (r(2) = 0.27), and RGC labeling of activated JUN protein increased. Atf3 mRNA levels demonstrated a positive linear correlation to the extent of injury (r(2) = 0.53), resulting in a nearly five-fold increase (482 +/- 76%) in eyes with the greatest nerve damage. Among downstream pro-survival signaling components, Erk5 mRNA expression was linearly upregulated (r(2) = 0.32) up to 157 +/- 15% of fellow values in retinas with the severest nerve injury (p < 0.01). A slight positive correlation was found between NF-kappaB message levels and injury extent (r(2) = 0.12). Bcl-xl mRNA levels in the most severely injured retinas were significantly reduced to 83 +/- 7% by elevated IOP exposure. Message levels for Erk1/2, Akt1-3 or Bcl2 appeared unaffected. Elevated IOP did not alter mRNA levels of pro-apoptotic Bim, Bax, or p53. This study demonstrates that elevated IOP exposure does not result in a dramatic decrease in retinal levels of either BDNF or its receptor, TrkB. It shows that the responses of NT pathways to elevated IOP are complex, particularly with regard to the role of p75(NTR) and Atf3. A better understanding of the roles of these proteins in IOP-induced injury is likely to suggest informed strategies for neuroprotection in glaucoma.
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Affiliation(s)
- Ying Guo
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, 3375 SW Terwilliger Blvd, Portland, OR 97239, USA.
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39
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Cell death and proliferation in acute slices and organotypic cultures of mammalian CNS. Prog Neurobiol 2009; 88:221-45. [DOI: 10.1016/j.pneurobio.2009.01.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 12/09/2008] [Accepted: 01/07/2009] [Indexed: 11/24/2022]
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40
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Beltran WA, Allore HG, Johnson E, Towle V, Tao W, Acland GM, Aguirre GD, Zeiss CJ. CREB1/ATF1 activation in photoreceptor degeneration and protection. Invest Ophthalmol Vis Sci 2009; 50:5355-63. [PMID: 19643965 DOI: 10.1167/iovs.09-3741] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The cAMP response element binding protein 1 (CREB1) and activating transcription factor 1 (ATF1) are closely related members of the bZIP superfamily of transcription factors. Both are activated in response to a wide array of stimuli, including cellular stress. This study was conducted to assess the CREB1/ATF1 pathway in photoreceptor disease and protection. METHODS The expression levels of p-CREB1, CREB1, and ATF1 were examined by immunoblot and immunohistochemistry in normal canine retina and retinas of several canine models of retinal degeneration (rcd1, rcd2, erd, prcd, XLPRA1, XLPRA2, T4R RHO). Humans retinas affected with age-related macular degeneration (AMD) were also examined. p-CREB1/ATF1 immunolabeling was assessed in normal and rcd1 dogs treated with ciliary neurotrophic factor (CNTF), to examine the effect of a neuroprotective stimulus on activation of CREB1/ATF1. RESULTS Native CREB1 and ATF1 as well as phosphorylated CREB1/ATF1 was examined in normal canine retina by immunoblot. The p-CREB1 antibody identified phosphorylated CREB1 and ATF1 and labeled the inner retina only in normal dogs. In degenerate canine and human retinas, strong immunolabeling appeared in rod and cone photoreceptors, indicating increased expression of native CREB1 and ATF1, as well as increased phosphorylation of these proteins. Retinal protection by CNTF in rcd1 dogs was accompanied by a significant increase in the number of p-CREB1/ATF1-labeled photoreceptor nuclei. CONCLUSIONS Positive association of CREB1/ATF1 phosphorylation with photoreceptor protection suggests that it may contribute to an innate protective response. These data identify a signaling mechanism in rods and cones of potential importance for therapies of RP and AMD.
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Affiliation(s)
- William A Beltran
- Section of Ophthalmology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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41
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Whitaker CM, Cooper NGF. The novel distribution of phosphodiesterase-4 subtypes within the rat retina. Neuroscience 2009; 163:1277-91. [PMID: 19638302 DOI: 10.1016/j.neuroscience.2009.07.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 01/01/2023]
Abstract
Phosphodiesterases (PDEs) are important regulators of signal transduction processes. While much is known about the function of cyclic GMP-specific PDEs in the retina, much less is known about the closely related, cyclic AMP-specific PDEs. The purpose of the present study is to characterize and localize PDE4 within the adult rat retina. We have used Western blotting, RT-PCR, and immunohistochemistry together with retrograde labeling to determine the presence and location of each PDE4 subtype. Western blot analysis revealed that multiple isoforms of PDE4A, B, and D subtypes are present within the retina, whereas the PDE4C subtype was absent. These data were confirmed by RT-PCR. Using immunohistochemistry we show that all three PDE4s are abundantly expressed within the retina where they all colocalize with retrograde-labeled retinal ganglion cells, as well as bipolar cells, horizontal cells, and cholinergic amacrine cells, whereas Müller cells lack PDE4 expression. Uniquely, PDE4B was expressed by the inner and outer segments of rod photoreceptors as well as their terminals within the outer plexiform layer. Collectively, our results demonstrate that PDE4s are abundantly expressed throughout the rodent retina and this study provides the framework for further functional studies.
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Affiliation(s)
- C M Whitaker
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
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42
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Ni YQ, Gan DK, Xu HD, Xu GZ, Da CD. Neuroprotective effect of transcorneal electrical stimulation on light-induced photoreceptor degeneration. Exp Neurol 2009; 219:439-52. [PMID: 19576889 DOI: 10.1016/j.expneurol.2009.06.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 06/17/2009] [Accepted: 06/20/2009] [Indexed: 10/20/2022]
Abstract
Direct electrical stimulation of neural tissues is a strategic approach to treat injured axons by accelerating their outgrowth [Al-Majed, A.A., Neumann, C.M., Brushart, T.M., Gordon, T., 2000. Brief electrical stimulation promotes the speed and accuracy of motor axonal regeneration. J. Neurosci. 20, 2602-2608] and promoting their regeneration [Geremia, N.M., Gordon, T., Brushart, T.M., Al-Majed, A.A., Verge, V.M.K., 2007. Electrical stimulation promotes sensory neuron regeneration and growth-associated gene expression. Exp. Neurol. 205, 347-359]. Recently, transcorneal electrical stimulation (TCES), a novel less invasive method, has been shown to rescue axotomized and damaged retinal ganglion cells [Morimoto, T., Miyoshi, T., Matsuda, S., Tano, Y., Fujikado, T., Fukuda, Y., 2005. Transcorneal electrical stimulation rescues axotomized retinal ganglion cells by activating endogenous retinal IGF-1 system. Invest. Ophthalmol. Vis. Sci. 46(6), 2147-2155]. Here, we investigated the neuroprotection of TCES on light-induced photoreceptor degeneration and the underlying mechanism. Adult male Sprague-Dawley (SD) rats received TCES before (pre-TCES) or after (post-TCES) intense light exposure. After fourteen days of light exposure, retinal histology and electroretinography were performed to evaluate the neuroprotective effect of TCES. The mRNA and protein levels of apoptotic-associated genes including Bcl-2, Bax, Caspase-3 as well as ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in the retinas were determined by real-time PCR and Western blot analysis. The localization of these gene products in the retinas was examined by immunohistochemistry. Both pre- and post-TCES ameliorated the progressive photoreceptor degeneration. The degree of rescue depended on the strength of the electric charge. Post-TCES showed a relatively better and longer-term protective effect than pre-TCES. Real-time PCR and Western blot analysis revealed an upregulation of Bcl-2, CNTF, and BDNF and a downregulation of Bax in the retinas after TCES. Immunohistochemical studies showed that Bcl-2 and CNTF were selectively upregulated in Müller cells. These findings provide a new therapeutic method to prevent or delay photoreceptor degeneration through activating the intrinsic survival system.
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Affiliation(s)
- Ying-qin Ni
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fen Yang Road, Shanghai 200031, People's Republic of China
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Gaddini L, Villa M, Matteucci A, Mallozzi C, Petrucci TC, Di Stasi AMM, Leo L, Malchiodi-Albedi F, Pricci F. Early effects of high glucose in retinal tissue cultures Renin-Angiotensin system-dependent and -independent signaling. Neurobiol Dis 2009; 35:278-85. [PMID: 19481149 DOI: 10.1016/j.nbd.2009.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/27/2009] [Accepted: 05/15/2009] [Indexed: 12/14/2022] Open
Abstract
The early effects of the diabetic milieu on retinal tissue and their relation to the Renin-Angiotensin system (RAS) activation are poorly known. Here we investigated RAS signaling in retinas explanted from adult rats exposed for 48 h to high glucose (HG), with or without the Angiotensin Converting Enzyme inhibitor enalaprilat, which blocks RAS. HG was observed to i) initiate a phosphotyrosine-dependent signaling cascade; ii) up-regulate Angiotensin(1) Receptor (AT(1)R); iii) activate src tyrosine kinase and increase phosphorylation of Pyk2, PLCgamma1 and ERK1/2; and iv) activate Akt and the transcription factor CREB. In the presence of enalaprilat, tyrosine phosphorylation signal and AT(1)R upregulation decreased and activation of PLCgamma1 and CREB reverted, showing their relation to RAS signaling. In line with Akt activation, no apoptosis or synapse degeneration was found. Müller glia was activated, but in a RAS-independent manner. Our results suggest that, in early phases of HG exposure, a pro-survival cell program may be induced in the retina.
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Affiliation(s)
- Lucia Gaddini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
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Johnson EC, Guo Y, Cepurna WO, Morrison JC. Neurotrophin roles in retinal ganglion cell survival: lessons from rat glaucoma models. Exp Eye Res 2009; 88:808-15. [PMID: 19217904 PMCID: PMC2704056 DOI: 10.1016/j.exer.2009.02.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 01/13/2009] [Accepted: 02/03/2009] [Indexed: 12/19/2022]
Abstract
The neurotrophin (NT) hypothesis proposes that the obstruction of retrograde transport at the optic nerve head results in the deprivation of neurotrophic support to retinal ganglion cells (RGC) leading to apoptotic cell death in glaucoma. An important corollary to this concept is the implication that appropriate enhancement of neurotrophic support will prolong the survival of injured RGC indefinitely. This hypothesis is, perhaps, the most widely recognized theory to explain RGC loss resulting from exposure of the eye to elevated intraocular pressure (IOP). Recent studies of NT signaling using rat glaucoma models, have examined the endogenous responses of the retina to pressure exposure as well as studies designed to augment NT signaling in order to rescue RGC from apoptosis following pressure-induced injury. The examination of these studies in this review reveals a number of consistent observations and provides direction for further investigations of this hypothesis.
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Affiliation(s)
- Elaine C Johnson
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, CERES, Oregon Health and Science University, Portland, OR 97239, USA.
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45
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Park HY, Lee NY, Kim JH, Park CK. Intraocular pressure lowering, change of antiapoptotic molecule expression, and neuroretinal changes by dorzolamide 2%/timolol 0.5% combination in a chronic ocular hypertension rat model. J Ocul Pharmacol Ther 2009; 24:563-71. [PMID: 19049297 DOI: 10.1089/jop.2008.0039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aim of this study was to examine intraocular pressure lowering, change of antiapoptotic molecules expression, and neuroretinal changes by a commercially available dorzolamide 2%/timolol 0.5% combination in a chronic ocular hypertension rat model. Chronic ocular hypertension was induced by three episcleral vein cauterizations. The expression of antiapoptotic molecules and the effect of dorzolamide 2%/timolol 0.5% combination in chronic ocular hypertensive retina were evaluated. Retinal ganglion cell (RGC) retrograde labeling and quantification with 4-di-10-ASP (DiA) and expression of glial fibrillary acidic protein (GFAP) were detected before and after the administration of dorzolamide 2%/timolol 0.5%. Treatment of ocular hypertensive eyes with dorzolamide 2%/timolol 0.5% significantly reduced, intraocular pressure when compared to the control eyes. Labeling of RGCs with DiA showed a significant decrease in RGC loss after the administration of dorzolamide 2%/timolol 0.5%. GFAP expression revealed a significant decrease in retinal damage after dorzolamide 2%/timolol 0.5% administration. However, dorzolamide 2%/timolol 0.5% did not affect Bcl-2 and Bcl-xL mRNA expression. In conclusion, dorzolamide 2%/timolol 0.5% may have neuroprotective potential in the animal model, which is not mediated by Bcl-2 or Bcl-xL. The mechanism of neuroprotection by dorzolamide 2%/timolol 0.5% in chronic glaucoma models requires further investigation.
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Affiliation(s)
- Hae Y Park
- Department of Ophthalmology and Visual Science, College of Medicine, St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
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Russo R, Rotiroti D, Tassorelli C, Nucci C, Bagetta G, Bucci MG, Corasaniti MT, Morrone LA. Identification of novel pharmacological targets to minimize excitotoxic retinal damage. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 85:407-23. [PMID: 19607984 DOI: 10.1016/s0074-7742(09)85028-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Excitotoxic neuronal death is a common feature of neurodegenerative and ischemic diseases of the central nervous system (CNS) and of a variety of ocular diseases, including glaucoma. Glaucoma, one of the leading causes of blindness in the world, is characterized by a progressive degeneration of retinal ganglion cells (RGCs) and their axons and is often associated with elevated intraocular pressure (IOP). Retinal ischemia/reperfusion induced by experimental elevation of IOP leads to damage and loss of RGCs. Under these conditions, structural, functional, and biochemical changes implicate the accumulation of extracellular glutamate and activation of the excitotoxic cascade. Beside the activation of associated pathways, death of RGCs is accompanied by impaired endogenous defenses, such as the PI3K/Akt prosurvival pathway. Original neurochemical and pharmacological evidence are discussed here to strengthen the role for excitotoxicity in RGCs death occurring in experimental, angle closure, glaucoma in conjunction with the discovery of novel molecular targets to potentiate endogenous prosurvival defenses in the glaucomatous retina.
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Affiliation(s)
- Rossella Russo
- Department of Pharmacobiology, University of Calabria, 87036 Arcavacata di Rende, Italy
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Surgucheva I, Shestopalov VI, Surguchov A. Effect of gamma-synuclein silencing on apoptotic pathways in retinal ganglion cells. J Biol Chem 2008; 283:36377-85. [PMID: 18936092 PMCID: PMC2606004 DOI: 10.1074/jbc.m806660200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/15/2008] [Indexed: 11/06/2022] Open
Abstract
gamma-Synuclein (Syn G) is highly expressed in retinal ganglion cells and the loss of these cells in glaucoma is associated with significant reduction of the intracellular Syn G level. However, a causative relationship between these two events has not been established. Here we show that the knockdown of Syn G results in a decreased viability of the immortalized retinal ganglion cells (RGC-5). The Syn G silencing reduces phosphorylation of serine 112 (Ser112) in Bad protein, a member of the Bcl-2 family that plays a critical role in apoptotic cell death signaling. Our gene expression analysis data suggests that changes in Bad phosphorylation status may be caused by a coordinated shift in activities of kinases controlling Bad phosphorylation and phosphatases catalyzing its dephosphorylation. Moreover, increased phosphorylation of Bad-sequestering protein 14-3-3 detected in these cells is also pro-apoptotic. These results suggest that the homeostatic level of Syn G in RGC-5 cells is required for transcriptional regulation of protein kinases and phosphatases, controlling phosphorylation of Bad and 14-3-3. Lowering Syn G causes Bad dephosphorylation, dissociation from phosphorylated 14-3-3, and translocation to mitochondria where it initiates apoptotic death cascade.
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Affiliation(s)
- Irina Surgucheva
- Laboratory of Retinal Biology, Veterans Affairs Medical Center, Kansas City, Missouri 64128, USA
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Li SY, Yau SY, Chen BY, Tay DK, Lee VWH, Pu ML, Chan HHL, So KF. Enhanced survival of melanopsin-expressing retinal ganglion cells after injury is associated with the PI3 K/Akt pathway. Cell Mol Neurobiol 2008; 28:1095-107. [PMID: 18512147 PMCID: PMC11514987 DOI: 10.1007/s10571-008-9286-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
In the present study, we studied the factors that contribute to the injury-resistant property of melanopsin-expressing retinal ganglion cells (mRGCs). Since phosphatidylinositol-3 kinase (PI3 K)/Akt signaling pathway is one of the well-known pathways for neuronal cell survival, we investigated the survival of mRGCs by applying the PI3 K/Akt specific inhibitors after injury. Two injury models, unilateral optic nerve transection and ocular hypertension, were adopted using Sprague-Dawley rats. Inhibitors of PI3 K/Akt were injected intravitreally following injuries to inhibit the PI3 K/Akt signaling pathway. Retinas were dissected after designated survival time, immunohistochemistry was carried out to visualize the mRGCs using melanopsin antibody and the number of mRGCs was counted. Co-expression of melanopsin and phospho-Akt (pAkt) was also examined. Compared to the survival of non-melanopsin-expressing RGCs, mRGCs showed a marked resistance to injury and co-expressed pAkt. Application of PI3 K/Akt inhibitors decreased the survival of mRGCs after injury. Our previous study has shown that mRGC are less susceptible to injury following the induction of ocular hypertension. In this study, we report that mRGCs were injury-resistant to a more severe type of injury, the optic nerve transection. More importantly, the PI3 K/Akt pathway was found to play a role in maintaining the survival of mRGCs after injury.
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Affiliation(s)
- Suk-Yee Li
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
- Eye Institute, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Suk-Yu Yau
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Bai-Yu Chen
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
- Department of Anatomy, Health Science Centre, Peking University, Beijing, China
| | - David K. Tay
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Vincent W. H. Lee
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- Mr. and Mrs. Tung Kay Fung Ophthalmic Laser Centre, Hong Kong Adventist Hospital, Hong Kong, China
| | - Ming-Liang Pu
- Department of Anatomy, Health Science Centre, Peking University, Beijing, China
| | - Henry H. L. Chan
- School of Optometry, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hum Hom, Hong Kong, China
| | - Kwok-Fai So
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Pokfulam, Hong Kong, China
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Russo R, Cavaliere F, Berliocchi L, Nucci C, Gliozzi M, Mazzei C, Tassorelli C, Corasaniti MT, Rotiroti D, Bagetta G, Morrone LA. Modulation of pro-survival and death-associated pathways under retinal ischemia/reperfusion: effects of NMDA receptor blockade. J Neurochem 2008; 107:1347-57. [DOI: 10.1111/j.1471-4159.2008.05694.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Yang X, Luo C, Cai J, Pierce WM, Tezel G. Phosphorylation-dependent interaction with 14-3-3 in the regulation of bad trafficking in retinal ganglion cells. Invest Ophthalmol Vis Sci 2008; 49:2483-94. [PMID: 18296656 DOI: 10.1167/iovs.07-1344] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To focus on the proteomic analysis of 14-3-3 proteins and to determine their cellular localization and functional role during glaucomatous neurodegeneration. METHODS Complementary proteomic approaches were used to identify phosphorylated proteins in a chronic pressure-induced rat model of glaucoma. To detect interacting proteins, specific protein complexes were eluted using coimmunoprecipitation and recombinant protein-based affinity pull-down for subsequent mass spectrometric analysis. Western blot analysis was performed for validation of the proteomic findings, and immunohistochemical analysis of rat eyes and human donor eyes determined the cellular localization of 14-3-3 proteins. In addition, in vivo treatment experiments were conducted using JNK and protein phosphatase inhibitors. RESULTS Findings of mass spectrometry, Western blotting, and tissue immunolabeling revealed the presence of different 14-3-3 isotopes in RGCs and their up-regulation and phosphorylation during glaucomatous neurodegeneration. Consecutive experiments through proteomic analysis identified various proteins interacting with 14-3-3, which included calmodulin and a proapoptotic member of the Bcl-2 family, Bad; 14-3-3 was found to keep phospho-Bad sequestered in the cytoplasm. However, this association was disrupted in ocular hypertensive eyes in correlation with Bad dephosphorylation and 14-3-3 phosphorylation, thereby leading to mitochondrial translocation of Bad for apoptotic function. Inhibition of JNK activity and of protein phosphatase activity complementarily secured the 14-3-3-scaffold of Bad in the cytoplasm and preserved optic nerve axons in ocular hypertensive eyes. CONCLUSIONS Findings of this in vivo study identify that an important protein family associated with checkpoint control pathways, 14-3-3, is involved in cellular signaling during glaucomatous neurodegeneration in a phosphorylation-dependent manner.
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Affiliation(s)
- Xiangjun Yang
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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