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Jiang J, Zhang L, Zou J, Liu J, Yang J, Jiang Q, Duan P, Jiang B. Phosphorylated S6K1 and 4E-BP1 play different roles in constitutively active Rheb-mediated retinal ganglion cell survival and axon regeneration after optic nerve injury. Neural Regen Res 2023; 18:2526-2534. [PMID: 37282486 PMCID: PMC10360084 DOI: 10.4103/1673-5374.371372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Ras homolog enriched in brain (Rheb) is a small GTPase that activates mammalian target of rapamycin complex 1 (mTORC1). Previous studies have shown that constitutively active Rheb can enhance the regeneration of sensory axons after spinal cord injury by activating downstream effectors of mTOR. S6K1 and 4E-BP1 are important downstream effectors of mTORC1. In this study, we investigated the role of Rheb/mTOR and its downstream effectors S6K1 and 4E-BP1 in the protection of retinal ganglion cells. We transfected an optic nerve crush mouse model with adeno-associated viral 2-mediated constitutively active Rheb and observed the effects on retinal ganglion cell survival and axon regeneration. We found that overexpression of constitutively active Rheb promoted survival of retinal ganglion cells in the acute (14 days) and chronic (21 and 42 days) stages of injury. We also found that either co-expression of the dominant-negative S6K1 mutant or the constitutively active 4E-BP1 mutant together with constitutively active Rheb markedly inhibited axon regeneration of retinal ganglion cells. This suggests that mTORC1-mediated S6K1 activation and 4E-BP1 inhibition were necessary components for constitutively active Rheb-induced axon regeneration. However, only S6K1 activation, but not 4E-BP1 knockdown, induced axon regeneration when applied alone. Furthermore, S6K1 activation promoted the survival of retinal ganglion cells at 14 days post-injury, whereas 4E-BP1 knockdown unexpectedly slightly decreased the survival of retinal ganglion cells at 14 days post-injury. Overexpression of constitutively active 4E-BP1 increased the survival of retinal ganglion cells at 14 days post-injury. Likewise, co-expressing constitutively active Rheb and constitutively active 4E-BP1 markedly increased the survival of retinal ganglion cells compared with overexpression of constitutively active Rheb alone at 14 days post-injury. These findings indicate that functional 4E-BP1 and S6K1 are neuroprotective and that 4E-BP1 may exert protective effects through a pathway at least partially independent of Rheb/mTOR. Together, our results show that constitutively active Rheb promotes the survival of retinal ganglion cells and axon regeneration through modulating S6K1 and 4E-BP1 activity. Phosphorylated S6K1 and 4E-BP1 promote axon regeneration but play an antagonistic role in the survival of retinal ganglion cells.
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Affiliation(s)
- Jikuan Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Lusi Zhang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingling Zou
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingyuan Liu
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jia Yang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Qian Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Peiyun Duan
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Bing Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
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2
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Zhao Y, Shen Y. Light-Induced Retinal Ganglion Cell Damage and the Relevant Mechanisms. Cell Mol Neurobiol 2020; 40:1243-1252. [PMID: 32107750 DOI: 10.1007/s10571-020-00819-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/18/2020] [Indexed: 12/21/2022]
Abstract
While light is the basic element for inducing vision and modulating circadian rhythms, excessive light has been reported to have a negative effect on the survival of various types of retinal cells. Among them photoreceptors and retinal pigment epithelial (RPE) cells degeneration after light exposure is widely observed, but light-induced retinal ganglion cell (RGC) damage achieves relatively little attention. The purpose of this article is to summarize the experimental evidence for the possible negative effects of excessive light on RGCs. By searching the database, twenty-six related articles have been included. Taken together, excessive light may insult RGCs through the three main ways: (i) directly action on RGC mitochondria, as well as DNA, resulting in an upregulation of reactive oxygen species (ROS) and subsequently caspase-dependent or -independent cell death; (ii) mediation in gliotransmitters or relevant receptors of retinal glial cells; and (iii) a secondary event to photoreceptors and RPE cells degeneration and subsequent retinal remodeling. So RGCs can certainly be injured by excessive light, especially when they are already energetically compromised in some diseases. And more attentions should be paid to this topic to take timely measures to protect these frail RGCs from being damaged by excessive light.
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Affiliation(s)
- Yuan Zhao
- Department of Ophthalmology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ye Shen
- Department of Ophthalmology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
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3
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McDougald DS, Papp TE, Zezulin AU, Zhou S, Bennett J. AKT3 Gene Transfer Promotes Anabolic Reprogramming and Photoreceptor Neuroprotection in a Pre-clinical Model of Retinitis Pigmentosa. Mol Ther 2019; 27:1313-1326. [PMID: 31043342 DOI: 10.1016/j.ymthe.2019.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 10/27/2022] Open
Abstract
Mutations within over 250 known genes are associated with inherited retinal degeneration. Clinical success following gene-replacement therapy for congenital blindness due to RPE65 mutations establishes a platform for the development of downstream treatments targeting other forms of inherited ocular disease. Unfortunately, several challenges relevant to complex disease pathology and limitations of current gene-transfer technologies impede the development of related strategies for each specific form of inherited retinal degeneration. Here, we describe a gene-augmentation strategy that delays retinal degeneration by stimulating features of anabolic metabolism necessary for survival and structural maintenance of photoreceptors. We targeted two critical points of regulation in the canonical insulin/AKT/mammalian target of rapamycin (mTOR) pathway with AAV-mediated gene augmentation in a mouse model of retinitis pigmentosa. AAV vectors expressing the serine/threonine kinase, AKT3, promote dramatic preservation of photoreceptor numbers, structure, and partial visual function. This protective effect was associated with successful reprogramming of photoreceptor metabolism toward pathways associated with cell growth and survival. Collectively, these findings underscore the importance of AKT activity and downstream pathways associated with anabolic metabolism in photoreceptor survival and maintenance.
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Affiliation(s)
- Devin S McDougald
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tyler E Papp
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandra U Zezulin
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shangzhen Zhou
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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4
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Ye D, Yang Y, Lu X, Xu Y, Shi Y, Chen H, Huang J. Spatiotemporal Expression Changes of PACAP and Its Receptors in Retinal Ganglion Cells After Optic Nerve Crush. J Mol Neurosci 2018; 68:465-474. [PMID: 30415445 DOI: 10.1007/s12031-018-1203-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/30/2018] [Indexed: 12/14/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) has been demonstrated to play a crucial part in protecting retinal ganglion cells (RGCs) from apoptosis in various retinal injury animal models. PACAP has two basic groups of receptors: PACAP receptor type 1 (PAC1R) and vasoactive intestinal polypeptide/PACAP receptors (VPAC1R and VPAC2R). However, few studies illustrated the spatial and temporal expression changes of endogenous PACAP and its receptors in a rodent optic nerve crush (ONC) model. In this study, a significant upregulation of PACAP and PAC1R in the retina after ONC was observed in both protein and RNA levels. The peak level of PACAP and PAC1R expression could be found on the fifth day following ONC. In addition, immunofluorescent labeling indicated that PACAP and PAC1R were localized mainly in RGCs. On the contrary, VPAC1R and VPAC2R were hardly detected in the retina. Collectively, the spatiotemporal expression of PACAP and its high-affinity receptor PAC1R were remarkably changed after ONC, and mainly expressed in the ganglion cell layer of the retina. This suggested that the upregulation of PACAP and PAC1R may play a vital role in RGC death after ONC.
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Affiliation(s)
- Dan Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Yao Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Xi Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Yue Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Yuxun Shi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Hailiu Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China
| | - Jingjing Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlienan Road, Guangzhou, 510060, China.
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5
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Chen XB, Wang ZL, Yang QY, Zhao FY, Qin XL, Tang XE, Du JL, Chen ZH, Zhang K, Huang FJ. Diosgenin Glucoside Protects against Spinal Cord Injury by Regulating Autophagy and Alleviating Apoptosis. Int J Mol Sci 2018; 19:ijms19082274. [PMID: 30072674 PMCID: PMC6121626 DOI: 10.3390/ijms19082274] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 12/25/2022] Open
Abstract
Spinal cord injury (SCI) is a severe traumatic lesion of central nervous system (CNS) with only a limited number of restorative therapeutic options. Diosgenin glucoside (DG), a major bioactive ingredient of Trillium tschonoskii Max., possesses neuroprotective effects through its antioxidant and anti-apoptotic functions. In this study, we investigated the therapeutic benefit and underlying mechanisms of DG treatment in SCI. We found that in Sprague-Dawley rats with traumatic SCI, the expressions of autophagy marker Light Chain 3 (LC3) and Beclin1 were decreased with concomitant accumulation of autophagy substrate protein p62 and ubiquitinated proteins, indicating an impaired autophagic activity. DG treatment, however, significantly attenuated p62 expression and upregulated the Rheb/mTOR signaling pathway (evidenced as Ras homolog enriched in brain) due to the downregulation of miR-155-3p. We also observed significantly less tissue injury and edema in the DG-treated group, leading to appreciable functional recovery compared to that of the control group. Overall, the observed neuroprotection afforded by DG treatment warrants further investigation on its therapeutic potential in SCI.
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Affiliation(s)
- Xian-Bing Chen
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu 610041, China.
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Zi-Li Wang
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Qing-Yu Yang
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Fang-Yu Zhao
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Xiao-Li Qin
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Xian-E Tang
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Jun-Long Du
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Zong-Hai Chen
- College of Medicine, Hubei University for Nationalities, Enshi 445000, China.
| | - Kui Zhang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu 610041, China.
| | - Fei-Jun Huang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu 610041, China.
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6
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Wang L, Du J, Zhao F, Chen Z, Chang J, Qin F, Wang Z, Wang F, Chen X, Chen N. Trillium tschonoskii maxim saponin mitigates D-galactose-induced brain aging of rats through rescuing dysfunctional autophagy mediated by Rheb-mTOR signal pathway. Biomed Pharmacother 2017; 98:516-522. [PMID: 29287199 DOI: 10.1016/j.biopha.2017.12.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 12/04/2017] [Accepted: 12/13/2017] [Indexed: 12/22/2022] Open
Abstract
During the expansion of aging population, the study correlated with brain aging is one of the important research topics. Developing novel and effective strategies for delaying brain aging is highly desired. Brain aging is characteristics of impaired cognitive capacity due to dysfunctional autophagy regulated by Rheb-mTOR signal pathway in hippocampal tissues. In the present study, we have established a rat model with brain aging through subcutaneous injection of D-galactose (D-gal). Upon the intervention of Trillium tschonoskii Maxim (TTM) saponin, one of bioactive components from local natural herbs in China, the learning and memory capacity of D-gal-induced aging rats was evaluated through Morris water maze test, and the regulation of Rheb-mTOR signal pathway and functional status of autophagy in hippocampal tissues of D-gal-induced aging rats was explored by Western blot. TTM saponin revealed an obvious function to improve learning and memory capacity of D-gal-induced aging rats through up-regulating Rheb and down-regulating mTOR, thereby rescuing dysfunctional autophagy to execute anti-aging role. Meanwhile, this study confirmed the function of TTM saponin for preventing and treating brain aging, and provided a reference for the development and utilization of natural products in health promotion and aging-associated disease treatment.
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Affiliation(s)
- Lingjie Wang
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Junlong Du
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Fangyu Zhao
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Zonghai Chen
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Jingru Chang
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, College of Health Science, Wuhan Sports University, Wuhan, 430079, China
| | - Furong Qin
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Zili Wang
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Fengjie Wang
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China
| | - Xianbing Chen
- College of Medicine, Hubei University for Nationalities, Enshi, 445000, China; Key Laboratory of Biological Resource Prevention and Utilization of Hubei Province, Enshi, 445000, China.
| | - Ning Chen
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, College of Health Science, Wuhan Sports University, Wuhan, 430079, China.
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7
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Vallée A, Lecarpentier Y, Guillevin R, Vallée JN. PPARγ agonists: Potential treatments for exudative age-related macular degeneration. Life Sci 2017; 188:123-130. [PMID: 28887057 DOI: 10.1016/j.lfs.2017.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/29/2017] [Accepted: 09/05/2017] [Indexed: 12/22/2022]
Abstract
Choroidal neovascularization (CNV) characterizes the progression of exudative age-related macular degeneration (AMD) with the deterioration in the central vision. Vascular inflammation, and overproduction of inflammatory cytokines, growth factors and aberrant endothelial cell migration, initiate defective blood vessel proliferation in exudative AMD. CNV formation is initiated by the interplay between inflammation, the hallmark of exudative AMD, and the activation of WNT/β-catenin pathway. Upregulation of WNT/β-catenin pathway involves activation of PI3K/Akt pathway and then the Warburg effect to produce lactate. Lactate production generates VEGF expression and then participates to the initiation of CNV in exudative AMD. WNT/β-catenin pathway and PPARγ act in an opposite manner in several diseases. We focus this review on the interplay between PPARγ and canonical WNT/β-catenin pathway and the anti-inflammatory role of PPARγ in exudative AMD. In exudative AMD, PPARγ agonists downregulate inflammation and the WNT/β-catenin pathway. PPARγ agonists can appear as promising treatment against the initiation and the progression of CNV in exudative AMD.
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Affiliation(s)
- Alexandre Vallée
- Experimental and Clinical Neurosciences Laboratory, INSERM U1084, University of Poitiers, Poitiers, France; Laboratoire de Mathématiques et Applications (LMA), UMR CNRS 7348, Université de Poitiers, France.
| | - Yves Lecarpentier
- Centre de Recherche Clinique, Grand Hôpital de l'Est Francilien (GHEF), Meaux, France
| | - Rémy Guillevin
- Université de Poitiers et CHU de Poitiers, DACTIM, Laboratoire de Mathématiques et Applications, UMR CNRS 7348, SP2MI, Futuroscope, France
| | - Jean-Noël Vallée
- Laboratoire de Mathématiques et Applications (LMA), UMR CNRS 7348, Université de Poitiers, France; CHU Amiens Picardie, Université Picardie Jules Verne (UPJV), Amiens, France
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8
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Potheraveedu VN, Schöpel M, Stoll R, Heumann R. Rheb in neuronal degeneration, regeneration, and connectivity. Biol Chem 2017; 398:589-606. [PMID: 28212107 DOI: 10.1515/hsz-2016-0312] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 02/02/2017] [Indexed: 01/31/2023]
Abstract
The small GTPase Rheb was originally detected as an immediate early response protein whose expression was induced by NMDA-dependent synaptic activity in the brain. Rheb's activity is highly regulated by its GTPase activating protein (GAP), the tuberous sclerosis complex protein, which stimulates the conversion from the active, GTP-loaded into the inactive, GDP-loaded conformation. Rheb has been established as an evolutionarily conserved molecular switch protein regulating cellular growth, cell volume, cell cycle, autophagy, and amino acid uptake. The subcellular localization of Rheb and its interacting proteins critically regulate its activity and function. In stem cells, constitutive activation of Rheb enhances differentiation at the expense of self-renewal partially explaining the adverse effects of deregulated Rheb in the mammalian brain. In the context of various cellular stress conditions such as oxidative stress, ER-stress, death factor signaling, and cellular aging, Rheb activation surprisingly enhances rather than prevents cellular degeneration. This review addresses cell type- and cell state-specific function(s) of Rheb and mainly focuses on neurons and their surrounding glial cells. Mechanisms will be discussed in the context of therapy that interferes with Rheb's activity using the antibiotic rapamycin or low molecular weight compounds.
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Affiliation(s)
- Veena Nambiar Potheraveedu
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
| | - Miriam Schöpel
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Raphael Stoll
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Rolf Heumann
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
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9
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Vallée A, Lecarpentier Y, Guillevin R, Vallée JN. Aerobic Glycolysis Hypothesis Through WNT/Beta-Catenin Pathway in Exudative Age-Related Macular Degeneration. J Mol Neurosci 2017; 62:368-379. [PMID: 28689265 DOI: 10.1007/s12031-017-0947-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 06/28/2017] [Indexed: 12/18/2022]
Abstract
Exudative age-related macular degeneration (AMD) is characterized by molecular mechanisms responsible for the initiation of choroidal neovascularization (CNV). Inflammatory processes are associated with upregulation of the canonical WNT/beta-catenin pathway in exudative AMD. We focus this review on the link between WNT/beta-catenin pathway activation and neovascular progression in exudative AMD through activation of aerobic glycolysis for production of angiogenic factors. Increased WNT/beta-catenin pathway involves hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2). WNT/beta-catenin pathway stimulates PI3K/Akt pathway and then HIF-1alpha which activates glycolytic enzymes: glucose transporter (Glut), pyruvate dehydrogenase kinase 1 (PDK1), lactate dehydrogenase A (LDH-A), and monocarboxylate lactate transporter (MCT-1). This phenomenon is called aerobic glycolysis or the Warburg effect. Consequently, phosphorylation of PDK-1 inhibits the pyruvate dehydrogenase complex (PDH). Thus, a large part of pyruvate cannot be converted into acetyl-CoA in mitochondria and only a part of acetyl-CoA can enter the tricarboxylic acid cycle. Cytosolic pyruvate is converted into lactate through the action of LDH-A. In exudative AMD, high level of cytosolic lactate is correlated with increase of VEGF expression, the angiogenic factor of CNV. Photoreceptors in retina cells can metabolize glucose through aerobic glycolysis to protect them against oxidative damage, as cancer cells do.
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Affiliation(s)
- Alexandre Vallée
- Experimental and Clinical Neurosciences Laboratory, INSERM U1084, University of Poitiers, Poitiers, France.
- Laboratoire de Mathématiques et Applications (LMA), UMR CNRS 7348, Université de Poitiers, 11 Boulevard Marie et Pierre Curie, Poitiers, France.
| | | | - Rémy Guillevin
- DACTIM, Laboratoire de Mathématiques et Applications, Université de Poitiers et CHU de Poitiers, UMR CNRS 7348, SP2MI Futuroscope, Chasseneuil-du-Poitou, France
| | - Jean-Noël Vallée
- Laboratoire de Mathématiques et Applications (LMA), UMR CNRS 7348, Université de Poitiers, 11 Boulevard Marie et Pierre Curie, Poitiers, France
- CHU Amiens Picardie, Université Picardie Jules Verne (UPJV), Amiens, France
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10
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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: 51] [Impact Index Per Article: 7.3] [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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11
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Yang X, Chen H, Zhu M, Zhu R, Qin B, Fang H, Dai M, Sang A, Liu X. Up-Regulation of PKM2 Relates to Retinal Ganglion Cell Apoptosis After Light-Induced Retinal Damage in Adult Rats. Cell Mol Neurobiol 2015; 35:1175-86. [PMID: 25990228 DOI: 10.1007/s10571-015-0211-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 05/13/2015] [Indexed: 01/09/2023]
Abstract
Pyruvate kinase isozyme type M2 (PKM2), a key glycolytic enzyme, which is involved in ATP generation and pyruvate production, participates in tumor metabolism, growth, and other multiple cellular processes. However, one attractive biological function of PKM2 is that it translocates to the nucleus and induces cell apoptosis. Recently, increased PKM2 has been found in age-related macular degeneration (AMD), but little is known regarding its function in the AMD pathophysiology. To investigate whether PKM2 participated in retinal degeneration, we performed a light-induced retinal damage model in adult rats. Western blot and immunohistochemistry analysis showed a significant up-regulation of PKM2 in retinal ganglion cells (RGCs) layer (GCL) after light exposure. Immunofluorescent labeling indicated that PKM2 located mainly in RGCs. Co-localization of PKM2 and active caspase-3 as well as TUNEL in RGCs suggested that PKM2 might participate in RGC apoptosis. In addition, the expression patterns of cyclin D1 and phosphorylated extracellular signal-regulated kinase (p-ERK) were parallel with that of PKM2. Furthermore, PKM2, cyclin D1, and active caspase-3 protein expression decreased by intravitreal injection of U0126, a highly selective inhibitor of MAPK/ERK kinase. Collectively, we hypothesized that PKM2 might participate in RGC apoptosis after light-induced retinal damage medicated by p-ERK through cycle re-entry mechanism.
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Affiliation(s)
- Xiaowei Yang
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Hui Chen
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Manhui Zhu
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Rongrong Zhu
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Bai Qin
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Hongda Fang
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Ming Dai
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Aimin Sang
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.
| | - Xiaojuan Liu
- Department of Pathogen Biology, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.
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Gu RP, Fu LL, Jiang CH, Xu YF, Wang X, Yu J. Retina Is Protected by Neuroserpin from Ischemic/Reperfusion-Induced Injury Independent of Tissue-Type Plasminogen Activator. PLoS One 2015; 10:e0130440. [PMID: 26176694 PMCID: PMC4503687 DOI: 10.1371/journal.pone.0130440] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 05/20/2015] [Indexed: 11/18/2022] Open
Abstract
The purpose of the present study was to investigate the potential neuroprotective effect of neuroserpin (NSP) on acute retinal ischemic/reperfusion-induced (IR) injury. An IR injury model was established by elevating intraocular pressure (IOP) for 60 minutes in wild type and tPA-deficient (tPA-/-) mice. Prior to IR injury, 1 μL of 20 μmol/L NSP or an equal volume of bovine serum albumin (BSA) was intravitreally administered. Retinal function was evaluated by electroretinograph (ERG) and the number of apoptotic neurons was determined via TUNEL labeling. Caspase-3, -8, -9,poly (ADP-ribose) polymerase (PARP)and their cleaved forms were subsequently analyzed. It was found that IR injury significantly damaged retinal function, inducing apoptosis in the retina, while NSP attenuated the loss of retinal function and significantly reduced the number of apoptotic neurons in both wild type and tPA-/- mice. The levels of cleaved caspase-3, cleaved PARP (the substrate of caspase-3) and caspase-9 (the modulator of the caspase-3), which had increased following IR injury, were significantly inhibited by NSP in both wild type and tPA-/- mice. NSP increased ischemic tolerance in the retina at least partially by inhibiting the intrinsic cell death signaling pathway of caspase-3. It was therefore concluded that the protective effect of neuroserpin maybe independent from its canonical interaction with a tissue-type plasminogen activator.
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Affiliation(s)
- R. P. Gu
- Department of Ophthalmology and Vision Sciences and Key Laboratory of Myopia of State Health Ministry, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China
| | - L. L. Fu
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - C. H. Jiang
- Department of Ophthalmology and Vision Sciences and Key Laboratory of Myopia of State Health Ministry, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China
- Department of Ophthalmology, No. 5 people’s Hospital of Shanghai, Shanghai, 200240, China
| | - Y. F. Xu
- Department of Ophthalmology and Vision Sciences and Key Laboratory of Myopia of State Health Ministry, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China
| | - X. Wang
- Department of Ophthalmology and Vision Sciences and Key Laboratory of Myopia of State Health Ministry, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China
| | - J. Yu
- Department of Ophthalmology and Vision Sciences and Key Laboratory of Myopia of State Health Ministry, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China
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13
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Sang A, Yang X, Chen H, Qin B, Zhu M, Dai M, Zhu R, Liu X. Upregulation of SYF2 Relates to Retinal Ganglion Cell Apoptosis and Retinal Glia Cell Proliferation After Light-Induced Retinal Damage. J Mol Neurosci 2015; 56:480-90. [DOI: 10.1007/s12031-015-0534-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 02/19/2015] [Indexed: 12/21/2022]
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14
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Huang Y, Xu Y, Cheng Q, Yu S, Gao Y, Shu Q, Yang C, Sun Y, Wang J, Xu F, Liang X. The expression changes of myelin and lymphocyte protein (MAL) following optic nerve crush in adult rats retinal ganglion cells. J Mol Neurosci 2014; 54:614-21. [PMID: 24878628 DOI: 10.1007/s12031-014-0332-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/13/2014] [Indexed: 01/09/2023]
Abstract
Myelin and lymphocyte protein (MAL), a component of compact myelin, is highly expressed in oligodendrocytes and Schwann cells. It has been reported that MAL may play a vital role in the process of neuronal apoptosis following acute spinal cord injury. However, acquaintance regarding its distribution and possible function in the retina is limited. Therefore, in a rodent model of optic nerve crush (ONC), the dynamic changes of MAL in retina was detected. The expression of MAL was mainly located in the retinal ganglion cells (RGCs) and was increased strongly after ONC. The peak of MAL expression appeared on the third day. In addition, there was a concomitant upregulation of active-caspase-3, which also co-localized with MAL in RGCs. Moreover, co-localization of MAL with terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling (TUNEL) was detected in RGCs after ONC. Collectively, all these results suggested that the upregulation of MAL might play an important role in the pathophysiology of RGCs after ONC.
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Affiliation(s)
- Yongsheng Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, People's Republic of China
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