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Yu N, Wu X, Zhang C, Qin Q, Gu Y, Ke W, Liu X, Zhang Q, Liu Z, Chen M, Wang K. NADPH and NAC synergistically inhibits chronic ocular hypertension-induced neurodegeneration and neuroinflammation through regulating p38/MAPK pathway and peroxidation. Biomed Pharmacother 2024; 175:116711. [PMID: 38735082 DOI: 10.1016/j.biopha.2024.116711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/14/2024] Open
Abstract
Glaucoma, the leading cause of irreversible blindness worldwide, is characterized by neurodegeneration and neuroinflammation with retinal NAD/NADP and GSH decline. Nicotinamide adenine dinucleotide (NAD)/NAD phosphate (NADP) and glutathione (GSH) are two redox reducers in neuronal and glial metabolism. However, therapeutic strategies targeting NAD/NADP or GSH do not exert ideal effects, and the underlying mechanisms are still poorly understood. We assessed morphological changes in retinal ganglion cells (RGCs), the affected neurons in glaucoma, and Müller cells, the major glial cells in the retina, as well as the levels of phosphorylated p38 (p-p38) and Caspase-3 in glaucoma patients. We constructed a modified chronic ocular hypertensive rat model and an oxygen-glucose deprivation (OGD) cell model. After applying NADPH and N-acetylcysteine (NAC), a precursor to cysteine, the rate-limiting substrate in GSH biosynthesis, to cells, apoptosis, axonal damage and peroxidation were reduced in the RGCs of the NAC group and p-p38 levels were decreased in the RGCs of the NADPH group, while in stimulated Müller cells cultured individually or cocultured with RGCs, gliosis and p38/MAPK, rather than JNK/MAPK, activation were inhibited. The results were more synergistic in the rat model, where either NADPH or NAC showed crossover effects on inhibiting peroxidation and p38/MAPK pathway activation. Moreover, the combination of NADPH and NAC ameliorated RGC electrophysiological function and prevented Müller cell gliosis to the greatest extent. These data illustrated conjoined mechanisms in glaucomatous RGC injury and Müller cell gliosis and suggested that NADPH and NAC collaborate as a neuroprotective and anti-inflammatory combination treatment for glaucoma and other underlying human neurodegenerative diseases.
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Affiliation(s)
- Naiji Yu
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Xingdi Wu
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Chengshou Zhang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Qiyu Qin
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Yuxiang Gu
- Department of Ophthalmology, The First People's Hospital of Xiaoshan District, Xiaoshan Affiliated Hospital of Wenzhou Medical University, Hangzhou, Zhejiang 311200, China
| | - Weishaer Ke
- Department of Ophthalmology, Xinjiang 474 Hospital, Urumqi, Xinjiang 841100, China
| | - Xin Liu
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Qi Zhang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China
| | - Zhenjie Liu
- Department of Vascular Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310000, China.
| | - Min Chen
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China.
| | - Kaijun Wang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang Provincial Key Laboratory of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Diseases, Hangzhou, Zhejiang 310000, China.
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Navneet S, Wilson K, Rohrer B. Müller Glial Cells in the Macula: Their Activation and Cell-Cell Interactions in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2024; 65:42. [PMID: 38416457 PMCID: PMC10910558 DOI: 10.1167/iovs.65.2.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/10/2024] [Indexed: 02/29/2024] Open
Abstract
Müller glia, the main glial cell of the retina, are critical for neuronal and vascular homeostasis in the retina. During age-related macular degeneration (AMD) pathogenesis, Müller glial activation, remodeling, and migrations are reported in the areas of retinal pigment epithelial (RPE) degeneration, photoreceptor loss, and choroidal neovascularization (CNV) lesions. Despite this evidence indicating glial activation localized to the regions of AMD pathogenesis, it is unclear whether these glial responses contribute to AMD pathology or occur merely as a bystander effect. In this review, we summarize how Müller glia are affected in AMD retinas and share a prospect on how Müller glial stress might directly contribute to the pathogenesis of AMD. The goal of this review is to highlight the need for future studies investigating the Müller cell's role in AMD. This may lead to a better understanding of AMD pathology, including the conversion from dry to wet AMD, which has no effective therapy currently and may shed light on drug intolerance and resistance to current treatments.
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Affiliation(s)
- Soumya Navneet
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kyrie Wilson
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, United States
- Ralph H. Johnson VA Medical Center, Division of Research, Charleston, South Carolina, United States
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Zhou YF, Liu HW, Yang X, Li CX, Chen JS, Chen ZP. Probucol attenuates high glucose-induced Müller cell damage through enhancing the Nrf2/p62 signaling pathway. Int Ophthalmol 2023; 43:4595-4604. [PMID: 37688651 PMCID: PMC10724314 DOI: 10.1007/s10792-023-02859-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 08/20/2023] [Indexed: 09/11/2023]
Abstract
PURPOSE This study investigated the protective effect of probucol on Müller cells exposed to high glucose conditions and examined potential mechanisms of action. METHODS Primary human retinal Müller cells were incubated with high glucose (HG, 35 mM) in the present or absence of different concentrations of probucol for 24 h. Cell viability was determined using the CCK-8 method. Mitochondrial membrane potential (MMP) was measured using JC-1 staining and cell cycle by flow cytometry. The expression of nuclear factor E2-related factor 2 (Nrf2), glutamate-cysteine ligase catalytic subunit, and p62 was quantified using quantitative polymerase chain reaction and western blot. RESULTS We found that HG inhibited cell proliferation, arrested cell cycle, and increased MMP in human Müller cells. Probucol activated the Nrf2/p62 pathway and upregulated the anti-apoptotic protein, Bcl2, and attenuated HG-mediated damage in Müller cells. CONCLUSIONS Our results suggest that probucol may protect Müller cells from HG-induced damage through enhancing the Nrf2/p62 signaling pathway.
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Affiliation(s)
- Yu-Fan Zhou
- Department of Ophthalmology, Aier Eye Hospital of Changsha, Changsha, 410015, Hunan Province, China
- Aier School of Ophthalmology, Central South University, Changsha, 410015, Hunan Province, China
| | - Heng-Wei Liu
- Department of Ophthalmology, Aier Eye Hospital of Changsha, Changsha, 410015, Hunan Province, China
- Aier School of Ophthalmology, Central South University, Changsha, 410015, Hunan Province, China
| | - Xu Yang
- Aier Eye Research Laboratory, Aier Eye Institute, Changsha, 410015, Hunan Province, China
| | - Chen-Xiang Li
- Department of Ophthalmology, Aier Eye Hospital of Changsha, Changsha, 410015, Hunan Province, China
- Aier School of Ophthalmology, Central South University, Changsha, 410015, Hunan Province, China
| | - Jian-Su Chen
- Aier School of Ophthalmology, Central South University, Changsha, 410015, Hunan Province, China
- Medical College, Jinan University, Guangzhou, 510632, Guangdong Province, China
| | - Zhong-Ping Chen
- Department of Ophthalmology, Aier Eye Hospital of Changsha, Changsha, 410015, Hunan Province, China.
- Aier School of Ophthalmology, Central South University, Changsha, 410015, Hunan Province, China.
- The First Clinical Medical College of Jinan University, Guangzhou, 510000, China.
- School of Stomatology and Ophthalmology, Xianning Medical College, Hubei University of Science and Technology, Xianning, 437100, China.
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Catalani E, Brunetti K, Del Quondam S, Cervia D. Targeting Mitochondrial Dysfunction and Oxidative Stress to Prevent the Neurodegeneration of Retinal Ganglion Cells. Antioxidants (Basel) 2023; 12:2011. [PMID: 38001864 PMCID: PMC10669517 DOI: 10.3390/antiox12112011] [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: 10/16/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
The imbalance of redox homeostasis contributes to neurodegeneration, including that related to the visual system. Mitochondria, essential in providing energy and responsible for several cell functions, are a significant source of reactive oxygen and/or nitrogen species, and they are, in turn, sensitive to free radical imbalance. Dysfunctional mitochondria are implicated in the development and progression of retinal pathologies and are directly involved in retinal neuronal degeneration. Retinal ganglion cells (RGCs) are higher energy consumers susceptible to mitochondrial dysfunctions that ultimately cause RGC loss. Proper redox balance and mitochondrial homeostasis are essential for maintaining healthy retinal conditions and inducing neuroprotection. In this respect, the antioxidant treatment approach is effective against neuronal oxidative damage and represents a challenge for retinal diseases. Here, we highlighted the latest findings about mitochondrial dysfunction in retinal pathologies linked to RGC degeneration and discussed redox-related strategies with potential neuroprotective properties.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, Largo dell’Università snc, 01100 Viterbo, Italy; (K.B.); (S.D.Q.)
| | | | | | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, Largo dell’Università snc, 01100 Viterbo, Italy; (K.B.); (S.D.Q.)
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Cha Z, Yin Z, A L, Ge L, Yang J, Huang X, Gao H, Chen X, Feng Z, Mo L, He J, Zhu S, Zhao M, Tao Z, Gu Z, Xu H. Fullerol rescues the light-induced retinal damage by modulating Müller glia cell fate. Redox Biol 2023; 67:102911. [PMID: 37816275 PMCID: PMC10570010 DOI: 10.1016/j.redox.2023.102911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/12/2023] Open
Abstract
Excessive light exposure can damage photoreceptors and lead to blindness. Oxidative stress serves a key role in photo-induced retinal damage. Free radical scavengers have been proven to protect against photo-damaged retinal degeneration. Fullerol, a potent antioxidant, has the potential to protect against ultraviolet-B (UVB)-induced cornea injury by activating the endogenous stem cells. However, its effects on cell fate determination of Müller glia (MG) between gliosis and de-differentiation remain unclear. Therefore, we established a MG lineage-tracing mouse model of light-induced retinal damage to examine the therapeutic effects of fullerol. Fullerol exhibited superior protection against light-induced retinal injury compared to glutathione (GSH) and reduced oxidative stress levels, inhibited gliosis by suppressing the TGF-β pathway, and enhanced the de-differentiation of MG cells. RNA sequencing revealed that transcription candidate pathways, including Nrf2 and Wnt10a pathways, were involved in fullerol-induced neuroprotection. Fullerol-mediated transcriptional changes were validated by qPCR, Western blotting, and immunostaining using mouse retinas and human-derived Müller cell lines MIO-M1 cells, confirming that fullerol possibly modulated the Nrf2, Wnt10a, and TGF-β pathways in MG, which suppressed gliosis and promoted the de-differentiation of MG in light-induced retinal degeneration, indicating its potential in treating retinal diseases.
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Affiliation(s)
- Zhe Cha
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Zhiyuan Yin
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Luodan A
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Lingling Ge
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Junling Yang
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Xiaona Huang
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Hui Gao
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Xia Chen
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Zhou Feng
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Lingyue Mo
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Juncai He
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China; Joint Logistics Support Force of Chinese PLA, No. 927 Hospital, Puer 665000, Yunnan, China
| | - Shuang Zhu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Maoru Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zui Tao
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China.
| | - Zhanjun Gu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Haiwei Xu
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China.
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Feng Y, Hu C, Cui K, Fan M, Xiang W, Ye D, Shi Y, Ye H, Bai X, Wei Y, Xu Y, Huang J. GSK840 Alleviates Retinal Neuronal Injury by Inhibiting RIPK3/MLKL-Mediated RGC Necroptosis After Ischemia/Reperfusion. Invest Ophthalmol Vis Sci 2023; 64:42. [PMID: 38015174 PMCID: PMC10691386 DOI: 10.1167/iovs.64.14.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Purpose This study aimed to explore the impact of GSK840 on retinal neuronal injury after retinal ischemia/reperfusion (IR) and its associated mechanism. Methods We established an in vivo mouse model of IR and an in vitro model of oxygen and glucose deprivation/reoxygenation (OGDR) in primary mouse retinal ganglion cells (RGCs). GSK840, a small-molecule compound, was used to specifically inhibit RIPK3/MLKL-dependent necroptosis. Retinal structure and function evaluation was performed by using hematoxylin and eosin staining, optical coherence tomography, and electroretinography. Propidium Iodide (PI) staining was used for detection of necroptotic cell death, whereas Western blot analysis and immunofluorescence were used to assess necroptosis-related proteins and inner retinal neurons. Results RIPK3/MLKL-dependent necroptosis was rapidly activated in RGCs following retinal IR or OGDR. GSK840 helped maintain relatively normal inner retinal structure and thickness by preserving inner retinal neurons, particularly RGCs. Meanwhile, GSK840 ameliorated IR-induced visual dysfunction, as evidenced by the improved amplitudes of photopic negative response, a-wave, b-wave, and oscillatory potentials. And GSK840 treatment significantly reduced the population of PI+ RGCs after injury. Mechanistically, GSK840 ameliorated RGC necroptosis by inhibiting the RIPK3/MLKL pathway. Conclusions GSK840 exerts protective effects against retinal neuronal injury after IR by inhibiting RIPK3/MLKL-mediated RGC necroptosis. GSK840 may represent a protective strategy for RGC degeneration in ischemic retinopathy.
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Affiliation(s)
- Yanlin Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Chenyang Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Kaixuan Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Matthew Fan
- Yale College, Yale University, New Haven, Connecticut, United States
| | - Wu Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Dan Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yuxun Shi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Huiwen Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xue Bai
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yantao Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yue Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jingjing Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Kaur B, Sharma PK, Chatterjee B, Bissa B, Nattarayan V, Ramasamy S, Bhat A, Lal M, Samaddar S, Banerjee S, Roy SS. Defective quality control autophagy in Hyperhomocysteinemia promotes ER stress and consequent neuronal apoptosis through proteotoxicity. Cell Commun Signal 2023; 21:258. [PMID: 37749555 PMCID: PMC10518934 DOI: 10.1186/s12964-023-01288-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/19/2023] [Indexed: 09/27/2023] Open
Abstract
Homocysteine (Hcy), produced physiologically in all cells, is an intermediate metabolite of methionine and cysteine metabolism. Hyperhomocysteinemia (HHcy) resulting from an in-born error of metabolism that leads to accumulation of high levels of Hcy, is associated with vascular damage, neurodegeneration and cognitive decline. Using a HHcy model in neuronal cells, primary cortical neurons and transgenic zebrafish, we demonstrate diminished autophagy and Hcy-induced neurotoxicity associated with mitochondrial dysfunction, fragmentation and apoptosis. We find this mitochondrial dysfunction is due to Hcy-induced proteotoxicity leading to ER stress. We show this sustained proteotoxicity originates from the perturbation of upstream autophagic pathways through an aberrant activation of mTOR and that protetoxic stress act as a feedforward cues to aggravate a sustained ER stress that culminate to mitochondrial apoptosis in HHcy model systems. Using chemical chaperones to mitigate sustained ER stress, Hcy-induced proteotoxicity and consequent neurotoxicity were rescued. We also rescue neuronal lethality by activation of autophagy and thereby reducing proteotoxicity and ER stress. Our findings pave the way to devise new strategies for the treatment of neural and cognitive pathologies reported in HHcy, by either activation of upstream autophagy or by suppression of downstream ER stress. Video Abstract.
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Affiliation(s)
- Bhavneet Kaur
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
| | - Pradeep Kumar Sharma
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Barun Chatterjee
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
| | - Bhawana Bissa
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Present address: Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, India
| | - Vasugi Nattarayan
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
| | - Soundhar Ramasamy
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
| | - Ajay Bhat
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
| | - Megha Lal
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India
| | | | | | - Soumya Sinha Roy
- CSIR-Institute of Genomics & Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, 110020, India.
- Academy of Scientific & Innovative Research, Ghaziabad, 201002, India.
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8
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Wang Q, Qiao Z, Kang W, Zhu L, Zhang X. Comparative analysis of co-culture and monoculture models in simulating diabetic neurovascular dysfunction: insights into diabetic retinopathy. Front Endocrinol (Lausanne) 2023; 14:1215218. [PMID: 37745714 PMCID: PMC10515208 DOI: 10.3389/fendo.2023.1215218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/17/2023] [Indexed: 09/26/2023] Open
Abstract
Background Interaction between retinal vascular endothelial cells and neurons plays a critical role in the pathogenesis of diabetic retinopathy (DR). This study aims to compare an in vitro model over a monoculture model to simulate the neurovascular coupling under the hyperglycemic microenvironment of diabetes. Methods Rat retinal vascular endothelial cells (RRMECs) and ganglion cells (RGCs) were seeded mono- or co-cultured in a normal (NG, 5.5 mM) and high (HG, 75 mM) glucose concentrations culture medium. Cell viability was detected by the cell counting kit-8 (CCK-8) assay. The ability of migration and lumen formation of RRMECs were determined by scratch wound, transwell migration, and lumen formation assays. The apoptosis index of cells was calculated and detected by propidium iodide (PI)/Hoechst staining. Quantitative and morphological analysis of RGCs was performed through the labeling of RGCs by brain-specific homeobox/POU domain protein 3A (BRN3A) and anti-beta-III tubulin (TUJ1). The gene and protein expression levels of occludin (OCLN) and zonula occludens-1 (ZO-1) were evaluated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Results The viability, migration, and lumen formation abilities of RRMECs in the HG group significantly increased (P<0.05) in both mono- and co-culture models. Migration and lumen formation abilities of RRMECs in the co-culture with HG were lower than that in the monoculture group (P<0.05). The viability of RGCs cells with HG significantly decreased in both mono- and co-culture models (Pmono<0.001, Pco<0.001), the apoptosis index of RGCs in the co-culture with HG was higher than that in the monoculture (P=0.010). The protein and gene expression of OCLN, and ZO-1 in RRMECs significantly decreased with HG culture medium in both culture models (P<0.05). In the HG group, the protein and gene expression level of the ZO-1 and OCLN of RRMECs significantly decreased in the co-culture model than that in the monoculture model (P<0.05). Conclusion Compared with mono cell culture, the established co-culture in vitro system for diabetic neurovascular dysfunction can better stimulate the micro-environment of the retinal neurovascular unit.
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Affiliation(s)
- Qiyun Wang
- Beijing Tongren Eye Center, Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Retinal and Choroidal Vascular Disorders Study Group, Beijing, China
| | - Zhixin Qiao
- Clinical Research Center, Tongren Hospital, Capital Medical University, Beijing, China
| | - Wenting Kang
- Clinical Research Center, Tongren Hospital, Capital Medical University, Beijing, China
| | - Ling Zhu
- Save Sight Institute, Department of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Xinyuan Zhang
- Beijing Tongren Eye Center, Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Retinal and Choroidal Vascular Disorders Study Group, Beijing, China
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9
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Liu S, Ji Y, Li H, Ren L, Zhu J, Yang T, Li X, Yao J, Cao X, Yan B. EYE-503: A Novel Retinoic Acid Drug for Treating Retinal Neurodegeneration. Pharmaceuticals (Basel) 2023; 16:1033. [PMID: 37513944 PMCID: PMC10386480 DOI: 10.3390/ph16071033] [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: 06/12/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Retinal neurodegeneration is a major cause of vision loss. Retinoic acid signaling is critical for the maintenance of retinal function, and its dysfunction can cause retinal neurodegeneration. However, the therapeutic effects of retinoic acid drugs on retinal neurodegeneration remain unclear. In this study, we designed a novel retinoic acid drug called EYE-503 and investigated its therapeutic effects of EYE-503 on retinal neurodegeneration. The optic nerve crush (ONC) model was selected for the retinal neurodegeneration study. H&E staining, TUNEL staining, immunofluorescence staining, and visual electrophysiology assays were performed to determine the role of EYE-503 in retinal neurodegeneration in vivo. The CCK-8 assay, EdU incorporation assay, PI staining, and flow cytometry assays were performed to investigate the effects of EYE-503 administration on retinal neurodegeneration in vitro. The potential mechanism of EYE-503 in retinal neurodegeneration was investigated by network pharmacology and Western blots. The results showed that EYE-503 administration had no detectable cytotoxicity and tissue toxicity. EYE-503 administration alleviated ONC-induced retinal injury and optic nerve injury in vivo. EYE-503 administration attenuated retinal ganglion cell apoptosis, inhibited reactive gliosis, and retarded the progression of retinal neurodegeneration. Mechanistically, EYE-503 regulated retinal neurodegeneration by targeting the JNK/p38 signaling pathway. This study suggests that EYE-503 is a promising therapeutic agent for retinal neurodegenerative diseases.
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Affiliation(s)
- Sha Liu
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Yuke Ji
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Huan Li
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Ling Ren
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
| | - Junya Zhu
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Tianjing Yang
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Xiumiao Li
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Jin Yao
- The Affiliated Eye Hospital, Nanjing Medical University, Nanjing 210093, China
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing 210093, China
| | - Xin Cao
- Institute of Clinical Science, Zhongshan Hospital, Fudan University, Shanghai 200433, China
| | - Biao Yan
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
- NHC Key Laboratory of Myopia, Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200433, China
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10
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Washington J, Ritch R, Liu Y. Homocysteine and Glaucoma. Int J Mol Sci 2023; 24:10790. [PMID: 37445966 DOI: 10.3390/ijms241310790] [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: 04/08/2023] [Revised: 06/10/2023] [Accepted: 06/11/2023] [Indexed: 07/15/2023] Open
Abstract
Elevated levels of homocysteine (Hcy), a non-proteinogenic amino acid, may lead to a host of manifestations across the biological systems, particularly the nervous system. Defects in Hcy metabolism have been associated with many neurodegenerative diseases including glaucoma, i.e., the leading cause of blindness. However, the pathophysiology of elevated Hcy and its eligibility as a risk factor for glaucoma remain unclear. We aimed to provide a comprehensive review of the relationship between elevated Hcy levels and glaucoma. Through a systemic search of the PubMed and Google Scholar databases, we found that elevated Hcy might play an important role in the pathogenesis of glaucoma. Further research will be necessary to help clarify the specific contribution of elevated Hcy in the pathogenesis of glaucoma. A discovery and conceptual understanding of Hcy-associated glaucoma could be the keys to providing better therapeutic treatment, if not prophylactic treatment, for this disease.
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Affiliation(s)
- Joshua Washington
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Robert Ritch
- New York Eye & Ear Infirmary, New York, NY 10003, USA
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- James & Jean Culver Vision Discovery Institute, 4 Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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11
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Zhang J, Zhang T, Zeng S, Zhang X, Zhou F, Gillies MC, Zhu L. The Role of Nrf2/sMAF Signalling in Retina Ageing and Retinal Diseases. Biomedicines 2023; 11:1512. [PMID: 37371607 DOI: 10.3390/biomedicines11061512] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/10/2023] [Accepted: 05/19/2023] [Indexed: 06/29/2023] Open
Abstract
Age-related diseases, such as Parkinson's disease, Alzheimer's disease, cardiovascular diseases, cancers, and age-related macular disease, have become increasingly prominent as the population ages. Oxygen is essential for living organisms, but it may also cause disease when it is transformed into reactive oxygen species via biological processes in cells. Most of the production of ROS occurs in mitochondrial complexes I and III. The accumulation of ROS in cells causes oxidative stress, which plays a crucial role in human ageing and many diseases. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a key antioxidant transcription factor that plays a central role in many diseases and ageing in general. It regulates many downstream antioxidative enzymes when cells are exposed to oxidative stress. A basic-region leucine zipper (bZIP) transcription factor, MAF, specifically the small MAF subfamily (sMAFs), forms heterodimers with Nrf2, which bind with Maf-recognition elements (MAREs) in response to oxidative stress. The role of this complex in the human retina remains unclear. This review summarises the current knowledge about Nrf2 and its downstream signalling, especially its cofactor-MAF, in ageing and diseases, with a focus on the retina. Since Nrf2 is the master regulator of redox homeostasis in cells, we hypothesise that targeting Nrf2 is a promising therapeutic approach for many age-related diseases.
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Affiliation(s)
- Jialing Zhang
- Save Sight Institute, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ting Zhang
- Save Sight Institute, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Shaoxue Zeng
- Save Sight Institute, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Xinyuan Zhang
- Department of Ocular Fundus Diseases, Beijing Tongren Eye Centre, Tongren Hospital, Capital Medical University, Beijing 100073, China
| | - Fanfan Zhou
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia
| | - Mark C Gillies
- Save Sight Institute, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ling Zhu
- Save Sight Institute, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
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12
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Barwick SR, Xiao H, Wolff D, Wang J, Perry E, Marshall B, Smith SB. Sigma 1 receptor activation improves retinal structure and function in the Rho P23H/+ mouse model of autosomal dominant retinitis pigmentosa. Exp Eye Res 2023; 230:109462. [PMID: 37003581 PMCID: PMC10155485 DOI: 10.1016/j.exer.2023.109462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/17/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
Retinitis pigmentosa (RP) is a group of devastating inherited retinal diseases that leads to visual impairment and oftentimes complete blindness. Currently no cure exists for RP thus research into prolonging vision is imperative. Sigma 1 receptor (Sig1R) is a promising small molecule target that has neuroprotective benefits in retinas of rapidly-degenerating mouse models. It is not clear whether Sig1R activation can provide similar neuroprotective benefits in more slowly-progressing RP models. Here, we examined Sig1R-mediated effects in the slowly-progressing RhoP23H/+ mouse, a model of autosomal dominant RP. We characterized the retinal degeneration of the RhoP23H/+ mouse over a 10 month period using three in vivo methods: Optomotor Response (OMR), Electroretinogram (ERG), and Spectral Domain-Optical Coherence Tomography (SD-OCT). A slow retinal degeneration was observed in both male and female RhoP23H/+ mice when compared to wild type. The OMR, which reflects visual acuity, showed a gradual decline through 10 months. Interestingly, female mice had more reduction in visual acuity than males. ERG assessment showed a gradual decline in scotopic and photopic responses in RhoP23H/+ mice. To investigate the neuroprotective benefits of Sig1R activation in the RhoP23H/+ mouse model, mutant mice were treated with a high-specificity Sig1R ligand (+)-pentazocine ((+)-PTZ) 3x/week at 0.5 mg/kg and examined using OMR, ERG, SD-OCT. A significant retention of visual function was observed in males and females at 10 months of age, with treated females retaining ∼50% greater visual acuity than non-treated mutant females. ERG revealed significant retention of scotopic and photopic b-wave amplitudes at 6 months in male and female RhoP23H/+ mice treated with (+)-PTZ. Further, in vivo analysis by SD-OCT revealed a significant retention of outer nuclear layer (ONL) thickness in male and female treated RhoP23H/+ mice. Histological studies showed significant retention of IS/OS length (∼50%), ONL thickness, and number of rows of photoreceptor cell nuclei at 6 months in (+)-PTZ-treated mutant mice. Interestingly, electron microscopy revealed preservation of OS discs in (+)-PTZ treated mutant mice compared to non-treated. Taken collectively, the in vivo and in vitro data provide the first evidence that targeting Sig1R can rescue visual function and structure in the RhoP23H/+ mouse. These results are promising and provide a framework for future studies to investigate Sig1R as a potential therapeutic target in retinal degenerative disease.
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Affiliation(s)
- Shannon R Barwick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.
| | - Haiyan Xiao
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - David Wolff
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Elizabeth Perry
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Brendan Marshall
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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13
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Kowluru RA, Alka K. Mitochondrial Quality Control and Metabolic Memory Phenomenon Associated with Continued Progression of Diabetic Retinopathy. Int J Mol Sci 2023; 24:ijms24098076. [PMID: 37175784 PMCID: PMC10179288 DOI: 10.3390/ijms24098076] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023] Open
Abstract
Diabetic retinopathy continues to progress even when hyperglycemia is terminated, suggesting a 'metabolic memory' phenomenon. Mitochondrial dysfunction is closely associated with the development of diabetic retinopathy, and mitochondria remain dysfunctional. Quality control of mitochondria requires a fine balance between mitochondrial fission-fusion, removal of the damaged mitochondria (mitophagy) and formation of new mitochondria (biogenesis). In diabetes, while mitochondrial fusion protein (Mfn2) is decreased, fission protein (Drp1) is increased, resulting in fragmented mitochondria. Re-institution of normal glycemia fails to reverse mitochondrial fragmentation, and dysfunctional mitochondria continue to accumulate. Our aim was to investigate the direct effect of regulation of the mitochondrial fusion process during normal glycemia that follows a high glucose insult on mitochondrial quality control in the 'metabolic memory' phenomenon. Human retinal endothelial cells, incubated in 20 mM glucose for four days, followed by 5 mM glucose for four additional days, with or without the Mfn2 activator leflunomide, were analyzed for mitochondrial fission (live cell imaging), mitophagy (flow cytometry and immunofluorescence microscopy), and mitochondrial mass (mitochondrial copy numbers and MitoTracker labeling). Mitochondrial health was determined by quantifying mitochondrial reactive oxygen species (ROS), respiration rate (Seahorse XF96) and mitochondrial DNA (mtDNA) damage. Addition of leflunomide during normal glucose exposure that followed high glucose prevented mitochondrial fission, facilitated mitophagy and increased mitochondrial mass. Glucose-induced decrease in mitochondrial respiration and increase in ROS and mtDNA damage were also prevented. Thus, direct regulation of mitochondrial dynamics can help maintain mitochondrial quality control and interfere with the metabolic memory phenomenon, preventing further progression of diabetic retinopathy.
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Affiliation(s)
- Renu A Kowluru
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Kumari Alka
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI 48201, USA
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14
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Controlling the Impact of Helicobacter pylori-Related Hyperhomocysteinemia on Neurodegeneration. Medicina (B Aires) 2023; 59:medicina59030504. [PMID: 36984505 PMCID: PMC10056452 DOI: 10.3390/medicina59030504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023] Open
Abstract
Helicobacter pylori infection consists a high global burden affecting more than 50% of the world’s population. It is implicated, beyond substantiated local gastric pathologies, i.e., peptic ulcers and gastric cancer, in the pathophysiology of several neurodegenerative disorders, mainly by inducing hyperhomocysteinemia-related brain cortical thinning (BCT). BCT has been advocated as a possible biomarker associated with neurodegenerative central nervous system disorders such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and/or glaucoma, termed as “ocular Alzheimer’s disease”. According to the infection hypothesis in relation to neurodegeneration, Helicobacter pylori as non-commensal gut microbiome has been advocated as trigger and/or mediator of neurodegenerative diseases, such as the development of Alzheimer’s disease. Among others, Helicobacter pylori-related inflammatory mediators, defensins, autophagy, vitamin D, dietary factors, role of probiotics, and some pathogenetic considerations including relevant involved genes are discussed within this opinion article. In conclusion, by controlling the impact of Helicobacter pylori-related hyperhomocysteinemia on neurodegenerative disorders might offer benefits, and additional research is warranted to clarify this crucial topic currently representing a major worldwide burden.
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15
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Samra YA, Zaidi Y, Rajpurohit P, Raghavan R, Cai L, Kaddour-Djebbar I, Tawfik A. Warburg Effect as a Novel Mechanism for Homocysteine-Induced Features of Age-Related Macular Degeneration. Int J Mol Sci 2023; 24:ijms24021071. [PMID: 36674587 PMCID: PMC9865636 DOI: 10.3390/ijms24021071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
Age-related macular degeneration (AMD) is a major cause of blindness. Recent studies have reported impaired glycolysis in AMD patients with a high lactate/pyruvate ratio. Elevated homocysteine (Hcy) (Hyperhomocysteinemia, HHcy) was observed in several clinical studies, reporting an association between HHcy and AMD. We established the effect of HHcy on barrier function, retinal pigment epithelium (RPE) structure, and induced choroidal neovascularization (CNV) in mice. We hypothesize that HHcy contributes to AMD by inducing a metabolic switch in the mitochondria, in which cells predominantly produce energy by the high rate of glycolysis, or "Warburg", effect. Increased glycolysis results in an increased production of lactate, cellular acidity, activation of angiogenesis, RPE barrier dysfunction, and CNV. Evaluation of cellular energy production under HHcy was assessed by seahorse analysis, immunofluorescence, and western blot experiments. The seahorse analysis evaluated the extracellular acidification rate (ECAR) as indicative of glycolysis. HHcy showed a significant increase in ECAR both in vivo using (Cystathionine β-synthase) cbs+/- and cbs-/- mice retinas and in vitro (Hcy-treated ARPE-19) compared to wild-type mice and RPE cells. Moreover, HHcy up-regulated glycolytic enzyme (Glucose transporter-1 (GlUT-1), lactate dehydrogenase (LDH), and hexokinase 1 (HK1)) in Hcy-treated ARPE-19 and primary RPE cells isolated from cbs+/+, cbs+/-, and cbs-/- mice retinas. Inhibition of GLUT-1 or blocking of N-methyl-D-aspartate receptors (NMDAR) reduced glycolysis in Hcy-treated RPE and improved albumin leakage and CNV induction in Hcy-injected mice eyes. The current study suggests that HHcy causes a metabolic switch in the RPE cells from mitochondrial respiration to glycolysis during AMD and confirms the involvement of NMDAR in this process. Therefore, targeting Glycolysis or NMDAR could be a novel therapeutic target for AMD.
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Affiliation(s)
- Yara A. Samra
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yusra Zaidi
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Pragya Rajpurohit
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Raju Raghavan
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Lun Cai
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Ismail Kaddour-Djebbar
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Charlie Norwood VA Medical Center, One Freedom Way, Augusta, GA 30904, USA
| | - Amany Tawfik
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
- Eye Research Institute, Oakland University, Rochester, MI 48309-4479, USA
- Eye Research Center (OUWB)/ERC, William Beaumont School of Medicine, Royal Oak, MI 48309-4479, USA
- Correspondence: ; Tel.: +1-248-370-2398; Fax: +1-248-370-4211
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16
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Inoue-Yanagimachi M, Himori N, Uchida K, Tawarayama H, Sato K, Yamamoto M, Namekata K, Harada T, Nakazawa T. Changes in glial cells and neurotrophic factors due to rotenone-induced oxidative stress in Nrf2 knockout mice. Exp Eye Res 2023; 226:109314. [PMID: 36400285 DOI: 10.1016/j.exer.2022.109314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 10/22/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Glaucoma is one of the most common causes of blindness worldwide. It is thought to be a multifactorial disease with underlying mechanisms that include mitochondrial dysfunction and oxidative stress. Here, we used NF-E2 related factor 2 (Nrf2) knockout (KO) mice, which are vulnerable to oxidative stress, to examine a neuroprotective effect against oxidative stress due to rotenone, a mitochondrial complex I inhibitor. Wild-type (WT) and Nrf2 KO mice received an oral solution of rotenone for 30 days. We then extracted the retinas and performed immunohistochemistry and quantitative RT-PCR. We also prepared a primary Müller cell culture of samples from each mouse, added 30 μM rotenone, and then measured cell viability, cytotoxicity and CellRox absorbance. We also examined gene expression. We found a significant increase in the number of 8-OHdG-positive retinal ganglion cells (RGCs) after rotenone administration in both the WT and Nrf2 KO mice. There was no difference in the number of RNA-binding protein with multiple splicing (RBPMS)-positive RGCs in the WT and Nrf2 KO mice, but Nrf2 KO mice that were given rotenone had significantly less retinal gene expression of RBPMS than Nrf2 KO mice given a control. Moreover, there was significantly higher mRNA gene expression of vimentin and glial fibrillary acidic protein (GFAP) in Nrf2 KO mice that received rotenone than WT mice that received rotenone. A statistical analysis of the in vitro experiment showed that cell viability was lower, cytotoxicity was higher, and oxidative stress was higher in the Müller cells of the Nrf2 KO mice than the WT mice. Finally, brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor (bFGF) were significantly higher in the Müller cells of the Nrf2 KO mice than the WT mice. These findings suggest that in Nrf2 KO mice under oxidative stress caused by rotenone, temporary neurotrophic factors are secreted from the Müller cells, conferring neuroprotection in these cells.
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Affiliation(s)
- Maki Inoue-Yanagimachi
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Noriko Himori
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Aging Vision Healthcare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
| | - Keiko Uchida
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hiroshi Tawarayama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kota Sato
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Japan; Collaborative Program for Ophthalmic Drug Discovery, Tohoku University Graduate School of Medicine, Sendai, Japan.
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17
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Robinson R, Glass J, Sharma A, Sharma S. Generation and characterization of a Müller-glial-cell-specific Il6ra knockout mouse to delineate the effects of IL-6 trans-signaling in the retina. Sci Rep 2022; 12:17626. [PMID: 36271280 PMCID: PMC9587029 DOI: 10.1038/s41598-022-22329-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/12/2022] [Indexed: 01/13/2023] Open
Abstract
Interleukin-6 (IL-6) is implicated in various retinal and vascular complications associated with diabetic retinopathy (DR). This cytokine functions through two main modalities: classical signaling, in cells expressing the membrane-bound receptor (IL-6Rα); and trans-signaling, possible in most cells through a soluble form of the receptor (sIL-6R). These pathways are considered to be anti-inflammatory and pro-inflammatory, respectively. Our recent studies in retinal endothelial cells and diabetic mice have shown that inhibiting only IL-6 trans-signaling is sufficient to prevent increased vascular leakage, oxidative stress, and inflammation characteristic of DR. Isolating the specific effects of each signaling pathway, however, remains difficult in cells expressing IL-6Rα that are thus capable of both classical and trans-signaling. Müller glial cells (MGCs), the most abundant retinal macroglial cells, span the entire retinal thickness with vital roles in maintaining retinal homeostasis and regulating the blood-retinal barrier through secreted factors. The specific effects of IL-6 trans-signaling in MGCs remain poorly understood given their responsiveness to both IL-6 signaling modalities. In this study, we addressed these concerns by generating an MGC-specific knockout mouse using Cre-loxP deletion of the Il6ra cytokine-binding region. We assessed transcriptional and translational Il6ra expression to confirm the knockout and characterized the effects of knockout on visual functioning in these mice.
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Affiliation(s)
- Rebekah Robinson
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, CAII 4139, Augusta, GA, 30912, USA
| | - Joshua Glass
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, CAII 4139, Augusta, GA, 30912, USA
| | - Ashok Sharma
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, CAII 4139, Augusta, GA, 30912, USA
- Department of Population Health Sciences, Augusta University, Augusta, GA, USA
- Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
- Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - Shruti Sharma
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, 1120 15th Street, CAII 4139, Augusta, GA, 30912, USA.
- Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.
- Department of Ophthalmology, Augusta University, Augusta, GA, USA.
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18
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Chen H, Wang M, Xia L, Dong J, Xu G, Wang Z, Feng L, Zhou Y. New Evidence of Central Nervous System Damage in Diabetes: Impairment of Fine Visual Discrimination. Diabetes 2022; 71:1772-1784. [PMID: 35612428 DOI: 10.2337/db21-0715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 05/04/2022] [Indexed: 11/13/2022]
Abstract
Diabetes can damage both the peripheral sensory organs, causing retinopathy, and the central visual system, leading to contrast sensitivity and impaired color vision in patients without retinopathy. Orientation discrimination is important for shape recognition by the visual system. Our psychophysical findings in this study show diminished orientation discrimination in patients with diabetes without retinopathy. To reveal the underlying mechanism, we established a diabetic mouse model and recorded in vivo electrophysiological data in the dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (V1). Reduced orientation selectivity was observed in both individual and populations of neurons in V1 and dLGN, which increased in severity with disease duration. This diabetes-associated neuronal dysfunction appeared earlier in the V1 than dLGN. Additionally, neuronal activity and signal-to-noise ratio are reduced in V1 neurons of diabetic mice, leading to a decreased capacity for information processing by V1 neurons. Notably, the V1 in diabetic mice exhibits reduced excitatory neuronal activity and lower levels of phosphorylated mammalian target of rapamycin (mTOR). Our findings show that altered responses of both populations of and single V1 neurons may impair fine vision, thus expanding our understanding of the underlying causes of diabetes-related impairment of the central nervous system.
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Affiliation(s)
- He Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Menghan Wang
- School of Information Science and Technology, University of Science and Technology of China, Hefei, China
| | - Lin Xia
- Department of Ophthalmology, First Affiliated Hospital of Anhui Medical University, Hefei, China
- Anhui Branch of National Clinical Research Center for Ocular Diseases, Hefei, China
| | - Jiong Dong
- Department of Ophthalmology, First Affiliated Hospital of Anhui Medical University, Hefei, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Hefei, China
| | - Guangwei Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ziyi Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Lixia Feng
- Department of Ophthalmology, First Affiliated Hospital of Anhui Medical University, Hefei, China
- Anhui Branch of National Clinical Research Center for Ocular Diseases, Hefei, China
| | - Yifeng Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Hefei, China
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Xu Z, Lei Y, Qin H, Zhang S, Li P, Yao K. Sigma-1 Receptor in Retina: Neuroprotective Effects and Potential Mechanisms. Int J Mol Sci 2022; 23:ijms23147572. [PMID: 35886921 PMCID: PMC9321618 DOI: 10.3390/ijms23147572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 02/04/2023] Open
Abstract
Retinal degenerative diseases are the major factors leading to severe visual impairment and even irreversible blindness worldwide. The therapeutic approach for retinal degenerative diseases is one extremely urgent and hot spot in science research. The sigma-1 receptor is a novel, multifunctional ligand-mediated molecular chaperone residing in endoplasmic reticulum (ER) membranes and the ER-associated mitochondrial membrane (ER-MAM); it is widely distributed in numerous organs and tissues of various species, providing protective effects on a variety of degenerative diseases. Over three decades, considerable research has manifested the neuroprotective function of sigma-1 receptor in the retina and has attempted to explore the molecular mechanism of action. In the present review, we will discuss neuroprotective effects of the sigma-1 receptor in retinal degenerative diseases, mainly in aspects of the following: the localization in different types of retinal neurons, the interactions of sigma-1 receptors with other molecules, the correlated signaling pathways, the influence of sigma-1 receptors to cellular functions, and the potential therapeutic effects on retinal degenerative diseases.
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Zhang H, Shen H, Gong W, Sun X, Jiang X, Wang J, Jin L, Xu X, Luo D, Wang X. Plasma homocysteine and macular thickness in older adults-the Rugao Longevity and Aging Study. Eye (Lond) 2022; 36:1050-1060. [PMID: 33976397 PMCID: PMC9046221 DOI: 10.1038/s41433-021-01549-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/08/2021] [Accepted: 04/09/2021] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES To determine the association of plasma homocysteine levels with retinal layer thickness in a large community cohort of older adults. METHODS The Rugao Longevity and Ageing Study is an observational, prospective and community-based cohort study. A total of 989 older adults who underwent spectral-domain optical coherence tomography (SD-OCT) were included and analyzed. Foveal, macular retinal nerve fibre layer (mRNFL) and ganglion cell layer plus inner plexiform layer (GC-IPL) thicknesses were measured by SD-OCT. Plasma homocysteine levels were measured using chemiluminescence immunoassay. Linear regression analyses were performed to evaluate the relationship between plasma homocysteine and retinal layer thickness while controlling for confounding factors. RESULTS Of the 989 participants, 500 (50.56%) were men. The mean age was 78.26 (4.58) years, and the mean plasma homocysteine level was 16.38 (8.05) μmol/L. In multivariable analyses, each unit increase in plasma homocysteine was associated with an 8.84 × 10-2 (95% CI: -16.54 × 10-2 to -1.15 × 10-2, p = 0.032) μm decrease in the average inner thickness of the GC-IPL after controlling for confounding factors. The association remained significant even in participants without major cardiovascular disease or diabetes (β = -10.33 × 10-2, 95% CI: -18.49 × 10-2 to -2.18 × 10-2, p = 0.013). No significant associations of plasma homocysteine levels with macular thickness or mRNFL were found in primary and sensitivity analyses (p > 0.05). CONCLUSIONS Increased plasma homocysteine levels are associated with a thinner GC-IPL. Plasma homocysteine may be a risk factor for thinner retinas in older adults.
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Affiliation(s)
- Hui Zhang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Hangqi Shen
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Wei Gong
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xuehui Sun
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Xiaoyan Jiang
- grid.24516.340000000123704535Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, China
| | - Jiucun Wang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Li Jin
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Xun Xu
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Dawei Luo
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xiaofeng Wang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China ,grid.413597.d0000 0004 1757 8802Shanghai Key Laboratory of Clinical Geriatric Medicine and Huadong Hospital Clinical Research Center for Geriatric Medicine, Shanghai, China ,grid.8547.e0000 0001 0125 2443National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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Effect of long-term chronic hyperhomocysteinemia on retinal structure and function in the cystathionine-β-synthase mutant mouse. Exp Eye Res 2022; 214:108894. [PMID: 34906600 PMCID: PMC9251730 DOI: 10.1016/j.exer.2021.108894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 02/03/2023]
Abstract
Elevated levels of the excitatory amino acid homocysteine (Hcy) have been implicated in retinal diseases in humans including glaucoma and macular degeneration. It is not clear whether elevated Hcy levels are pathogenic. Models of hyperhomocysteinemia (Hhcy) have proven useful in addressing this including mice with deficiency in the enzyme cystathionine β-synthase (CBS). Cbs+/- mice have a ∼two-fold increase in plasma and retinal Hcy levels. Previous studies of visual function and structure in Cbs+/- mice during the first 10 months of life revealed mild ganglion cell loss, but minimal electrophysiological alterations. It is not clear whether extended, chronic exposure to moderate Hhcy elevation will lead to visual function loss and retinal pathology. The present study addressed this by performing comprehensive analyses of retinal function/structure in 20 month Cbs+/- and Cbs+/+ (WT) mice including IOP, SD-OCT, scotopic and photopic ERG, pattern ERG (pERG), and visual acuity. Eyes were harvested for histology and immunohistochemical analysis of Brn3a (ganglion cells), dihydroethidium (oxidative stress) and GFAP (gliosis). The analyses revealed no difference in IOP between groups for age/strain. Visual acuity measured ∼0.36c/d for mice at 20 months in Cbs+/- and WT mice; contrast sensitivity did not differ between groups at either age. Similarly SD-OCT, scotopic/photopic ERG and pERG revealed no differences between 20 month Cbs+/- and WT mice. There was minimal disruption in retinal structure when eyes were examined histologically. Morphometric analysis revealed no significant differences in retinal layers. Immunohistochemistry revealed ∼5 RGCs/100 μm retinal length in both Cbs+/- and WT mice at 20 months. While there was greater oxidative stress and gliosis in older (20 month) mice versus young (4 month) mice, there was no difference in these parameters between the 20 month Cbs+/- and WT mice. We conclude that chronic, moderate Hhcy (at least due to deficiency of Cbs) is not accompanied by retinal structural/functional changes that differ significantly from age-matched WT littermates. Despite considerable evidence that severe Hhcy is toxic to retina, moderate Hhcy appears tolerated by retina suggesting compensatory cellular survival mechanisms.
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22
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Tabibzadeh S. Resolving Geroplasticity to the Balance of Rejuvenins and Geriatrins. Aging Dis 2022; 13:1664-1714. [DOI: 10.14336/ad.2022.0414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/14/2022] [Indexed: 11/18/2022] Open
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Tribble JR, Otmani A, Sun S, Ellis SA, Cimaglia G, Vohra R, Jöe M, Lardner E, Venkataraman AP, Domínguez-Vicent A, Kokkali E, Rho S, Jóhannesson G, Burgess RW, Fuerst PG, Brautaset R, Kolko M, Morgan JE, Crowston JG, Votruba M, Williams PA. Nicotinamide provides neuroprotection in glaucoma by protecting against mitochondrial and metabolic dysfunction. Redox Biol 2021; 43:101988. [PMID: 33932867 PMCID: PMC8103000 DOI: 10.1016/j.redox.2021.101988] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD) is a REDOX cofactor and metabolite essential for neuronal survival. Glaucoma is a common neurodegenerative disease in which neuronal levels of NAD decline. We assess the effects of nicotinamide (a precursor to NAD) on retinal ganglion cells (the affected neuron in glaucoma) in normal physiological conditions and across a range of glaucoma relevant insults including mitochondrial stress and axon degenerative insults. We demonstrate retinal ganglion cell somal, axonal, and dendritic neuroprotection by nicotinamide in rodent models which represent isolated ocular hypertensive, axon degenerative, and mitochondrial degenerative insults. We performed metabolomics enriched for small molecular weight metabolites for the retina, optic nerve, and superior colliculus which demonstrates that ocular hypertension induces widespread metabolic disruption, including consistent changes to α-ketoglutaric acid, creatine/creatinine, homocysteine, and glycerophosphocholine. This metabolic disruption is prevented by nicotinamide. Nicotinamide provides further neuroprotective effects by increasing oxidative phosphorylation, buffering and preventing metabolic stress, and increasing mitochondrial size and motility whilst simultaneously dampening action potential firing frequency. These data support continued determination of the utility of long-term nicotinamide treatment as a neuroprotective therapy for human glaucoma. Nicotinamide is neuroprotective in cell and animal models that recapitulate isolated features of glaucoma. Systemic nicotinamide administration has limited molecular side-effects on visual system tissue under basal conditions. Nicotinamide provides a robust reversal in the disease metabolic profile of glaucomatous animals. Nicotinamide increases oxidative phosphorylation, buffers and prevents metabolic stress, and increases mitochondrial size.
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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.
| | - Amin Otmani
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Shanshan Sun
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Sevannah A Ellis
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia.
| | - Gloria Cimaglia
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden; School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Rupali Vohra
- Department of Veterinary and Animal Sciences, Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Melissa Jöe
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Emma Lardner
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Abinaya P Venkataraman
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Alberto Domínguez-Vicent
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Eirini Kokkali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Seungsoo Rho
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
| | - Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden; Wallenberg Centre of Molecular Medicine, Umeå University, Umeå, Sweden.
| | | | - Peter G Fuerst
- WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA.
| | - Rune Brautaset
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark.
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK; School of Medicine, Cardiff University, Cardiff, UK.
| | - Jonathan G Crowston
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore; Centre for Vision Research, Neuroscience and Behavioural Disorders, Duke-NUS, Singapore, Singapore.
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK.
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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Wyse ATS, Bobermin LD, Dos Santos TM, Quincozes-Santos A. Homocysteine and Gliotoxicity. Neurotox Res 2021; 39:966-974. [PMID: 33786757 DOI: 10.1007/s12640-021-00359-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/15/2022]
Abstract
Homocysteine is a sulfur amino acid that does not occur in the diet, but it is an essential intermediate in normal mammalian metabolism of methionine. Hyperhomocysteinemia results from dietary intakes of Met, folate, and vitamin B12 and lifestyle or from the deficiency of specific enzymes, leading to tissue accumulation of this amino acid and/or its metabolites. Severe hyperhomocysteinemic patients can present neurological symptoms and structural brain abnormalities, of which the pathogenesis is poorly understood. Moreover, a possible link between homocysteine (mild hyperhomocysteinemia) and neurodegenerative/neuropsychiatric disorders has been suggested. In recent years, increasing evidence has emerged suggesting that astrocyte dysfunction is involved in the neurotoxicity of homocysteine and possibly associated with the physiopathology of hyperhomocysteinemia. This review addresses some of the findings obtained from in vivo and in vitro experimental models, indicating high homocysteine levels as an important neurotoxin determinant of the neuropathophysiology of brain damage. Recent data show that this amino acid impairs glutamate uptake, redox/mitochondrial homeostasis, inflammatory response, and cell signaling pathways. Therefore, the discussion of this review focuses on homocysteine-induced gliotoxicity, and its impacts in the brain functions. Through understanding the Hcy-induced gliotoxicity, novel preventive/therapeutic strategies might emerge for these diseases.
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Affiliation(s)
- Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - Larissa Daniele Bobermin
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Tiago Marcon Dos Santos
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Wang J, Xiao H, Barwick S, Liu Y, Smith SB. Optimal timing for activation of sigma 1 receptor in the Pde6b rd10/J (rd10) mouse model of retinitis pigmentosa. Exp Eye Res 2021; 202:108397. [PMID: 33310057 PMCID: PMC7808329 DOI: 10.1016/j.exer.2020.108397] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/24/2020] [Accepted: 12/07/2020] [Indexed: 11/18/2022]
Abstract
Sigma 1 Receptor (Sig1R), a pluripotent modulator of cell survival, is a promising target for treatment of retinal degenerative diseases. Previously, we reported that administration of the high-affinity, high-specificity Sig1R ligand (+)-pentazocine, ((+)-PTZ) beginning at post-natal day 14 (P14) and continuing every other day improves visual acuity and delays loss of photoreceptor cells (PRCs) in the Pde6βrd10/J (rd10) mouse model of retinitis pigmentosa. Whether administration of (+)-PTZ, at time points concomitant with (P18) or following (P21, P24) onset of PRC death, would prove neuroprotective was investigated in this study. Rd10 mice were administered (+)-PTZ intraperitoneally [0.5 mg/kg], starting at either P14, P18, P21 or P24. Injections continued every other day through P42. Visual acuity was assessed using the optokinetic tracking response (OKR). Rd10 mice treated with (+)-PTZ beginning at P14 retained visual acuity for the duration of the study (~0.33 c/d at P21, ~0.38 c/d at P28, ~0.32 c/d at P35, ~0.32 c/d at P42), whereas mice injected beginning at P18, P21, P24 showed a decline in acuity when tested at P35 and P42. Their acuity was only slightly better than rd10-non-treated mice. Electrophysiologic function was assessed using scotopic and photopic electroretinography (ERG) to assess rod and cone function, respectively. Photopic a- and b-wave amplitudes were significantly greater in rd10 mice treated with (+)-PTZ beginning at P14 compared with non-treated mice and those in the later-onset (+)-PTZ injection groups. Retinal architecture was visualized in living mice using spectral domain-optical coherence tomography (SD-OCT) allowing measurement of the total retinal thickness, the inner retina and the outer retina (the area most affected in rd10 mice). The outer retina measured ~35 μm in rd10 mice treated with (+)-PTZ beginning at P14, which was significantly greater than mice in the later-onset (+)-PTZ injection groups (~25 μm) and non-treated rd10 mice (~25 μm). Following the visual function studies performed in the living mice, eyes were harvested at P42 for histologic analysis. While the inner retina was largely intact in all (+)-PTZ-injection groups, there was a marked reduction in the outer retina of non-treated rd10 mice (e.g. in the outer nuclear layer there were ~10 PRCs/100 μm retinal length). The rd10 mice treated with (+)-PTZ beginning at P14 had ~20 PRCs/100 μm retinal length, whereas the mice in groups beginning P18, P21 and P24 had ~16 PRCs/100 μm retinal length. In conclusion, the data indicate that delaying (+)-PTZ injection past the onset of PRC death in rd10 mice - even by a few days - can negatively impact the long-term preservation of retinal function. Our findings suggest that optimizing the administration of Sig1R ligands is critical for retinal neuroprotection.
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Affiliation(s)
- Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, United States
| | - Haiyan Xiao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, United States
| | - Shannon Barwick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, United States
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, United States
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, United States; Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA, United States.
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Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina. MICROMACHINES 2020; 11:mi11121089. [PMID: 33316971 PMCID: PMC7763644 DOI: 10.3390/mi11121089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022]
Abstract
Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.
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Wang J, Xiao H, Barwick SR, Smith SB. Comparison of Sigma 1 Receptor Ligands SA4503 and PRE084 to (+)-Pentazocine in the rd10 Mouse Model of RP. Invest Ophthalmol Vis Sci 2020; 61:3. [PMID: 33137196 PMCID: PMC7645203 DOI: 10.1167/iovs.61.13.3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/07/2020] [Indexed: 12/18/2022] Open
Abstract
Purpose Sigma 1 receptor is a novel therapeutic target for retinal disease. Its activation, using a high-affinity, high-specificity ligand (+)-pentazocine ((+)-PTZ), rescues photoreceptor cells in the rd10 mouse model of RP. Here, we asked whether the robust retinal neuroprotective properties of (+)-PTZ are generalizable to SA4503 and PRE084, two other high-affinity sigma 1 receptor ligands. Methods We treated 661W cells with SA4503 or PRE084. Cell viability, oxidative stress, and expression of Nrf2 and NRF2-regulated antioxidant genes (Nqo1, Cat, and Sod1) were assessed. Rd10 mice were administered SA4503 (1 mg/kg), PRE084 (0.5 mg/kg), or (+)-PTZ (0.5 mg/kg). Visual acuity, retinal architecture, and retinal electrophysiologic function were measured in vivo and retinal structure was assessed histologically. Results Similar to (+)-PTZ, SA4503 and PRE084 improved cell viability, attenuated oxidative stress, and increased Nrf2, Nqo1 and Cat expression. Although treatment of rd10 mice with (+)-PTZ improved visual acuity, increased outer retinal thickness, and improved photopic a- and b-wave responses compared with nontreated rd10 mice, treatment with SA4503 or PRE084 did not. The number of photoreceptor nuclei/100 µm retinal length in SA4503- and PRE084-treated rd10 mice (approximately 11/100) did not differ significantly from nontreated rd10 mice, whereas (+)-PTZ-treated mice had significantly more nuclei (approximately 22/100 µm). Conclusions Cell survival and gene regulation experiments yielded similar outcomes when SA4503, PRE084, or (+)-PTZ were conducted in vitro, however neither SA4503 or PRE084 afforded in vivo protection in the severe rd10 retinopathy model comparable to (+)-PTZ. Despite all three compounds demonstrating the potential to activate sigma 1 receptor, the retinal neuroprotective properties of the three ligands differ significantly.
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Affiliation(s)
- Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Haiyan Xiao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Shannon R. Barwick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Sylvia B. Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
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Kaplan P, Tatarkova Z, Sivonova MK, Racay P, Lehotsky J. Homocysteine and Mitochondria in Cardiovascular and Cerebrovascular Systems. Int J Mol Sci 2020; 21:ijms21207698. [PMID: 33080955 PMCID: PMC7589705 DOI: 10.3390/ijms21207698] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/20/2022] Open
Abstract
Elevated concentration of homocysteine (Hcy) in the blood plasma, hyperhomocysteinemia (HHcy), has been implicated in various disorders, including cardiovascular and neurodegenerative diseases. Accumulating evidence indicates that pathophysiology of these diseases is linked with mitochondrial dysfunction. In this review, we discuss the current knowledge concerning the effects of HHcy on mitochondrial homeostasis, including energy metabolism, mitochondrial apoptotic pathway, and mitochondrial dynamics. The recent studies suggest that the interaction between Hcy and mitochondria is complex, and reactive oxygen species (ROS) are possible mediators of Hcy effects. We focus on mechanisms contributing to HHcy-associated oxidative stress, such as sources of ROS generation and alterations in antioxidant defense resulting from altered gene expression and post-translational modifications of proteins. Moreover, we discuss some recent findings suggesting that HHcy may have beneficial effects on mitochondrial ROS homeostasis and antioxidant defense. A better understanding of complex mechanisms through which Hcy affects mitochondrial functions could contribute to the development of more specific therapeutic strategies targeted at HHcy-associated disorders.
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Natural Products: Evidence for Neuroprotection to Be Exploited in Glaucoma. Nutrients 2020; 12:nu12103158. [PMID: 33081127 PMCID: PMC7602834 DOI: 10.3390/nu12103158] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/14/2022] Open
Abstract
Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.
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Zhang W, Kong Y. YAP is essential for TGF-β-induced retinal fibrosis in diabetic rats via promoting the fibrogenic activity of Müller cells. J Cell Mol Med 2020; 24:12390-12400. [PMID: 32951332 PMCID: PMC7686973 DOI: 10.1111/jcmm.15739] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/23/2020] [Accepted: 07/30/2020] [Indexed: 12/11/2022] Open
Abstract
The purpose of this study was to investigate whether Yes-associated protein (YAP) activation and proliferation of retinal Müller cells play a role in the development of TGF-β-induced retinal fibrosis. We studied the effects of YAP activation on retinal fibrosis in diabetic rats and human retinal Müller cells (hMCs) in vitro. The retinal expression of YAP and fibrogenic molecules in rats was detected using Western blotting and immunohistochemistry. After treatment with transforming growth factor-β1 (TGF-β1), the levels of fibrogenic molecules, and the activation of YAP and PI3K/Akt signalling pathway in hMCs were detected with Western blotting. The effect of YAP on retinal fibrotic changes was evaluated using YAP knockdown experiments and YAP inhibitors. Results showed that YAP expression was increased in the retina of diabetic rats along with increased retinal fibrosis. In cultured hMCs, YAP inhibition suppressed TGF-β1-stimulated hMC differentiation to myofibroblasts and extracellular matrix (ECM) production, while YAP activation promoted hMC differentiation and ECM production independent of TGF-β1. Furthermore, hMCs cultured on a gel with greater stiffness differentiated into myofibroblasts in a YAP-dependent manner. In diabetic rats, treatment with the YAP inhibitor verteporfin suppressed retinal fibrogenesis. In addition, the TGF-β1-induced PI3K/Akt signalling pathway mediated YAP activation as well as expression of fibrogenic molecules. The interaction between ECM stiffness and YAP forms a feed-forward process leading to retinal fibrosis. Our work highlights YAP as an essential regulator of pro-fibrotic responses in TGF-β-induced retinal fibrosis.
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Affiliation(s)
- Wei Zhang
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Clinical College of Ophthalmology Tianjin Medical University, Tianjin, China
| | - Yichun Kong
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Clinical College of Ophthalmology Tianjin Medical University, Tianjin, China.,Tianjin NanKai Hospital, NanKai Hospital, Tianjin Medical University, Nankai university affiliated Nankai hospital, Tianjin, China
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Diabetic Retinopathy: Mitochondria Caught in a Muddle of Homocysteine. J Clin Med 2020; 9:jcm9093019. [PMID: 32961662 PMCID: PMC7564979 DOI: 10.3390/jcm9093019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/09/2020] [Accepted: 09/17/2020] [Indexed: 12/17/2022] Open
Abstract
Diabetic retinopathy is one of the most feared complications of diabetes. In addition to the severity of hyperglycemia, systemic factors also play an important role in its development. Another risk factor in the development of diabetic retinopathy is elevated levels of homocysteine, a non-protein amino acid, and hyperglycemia and homocysteine are shown to produce synergistic detrimental effects on the vasculature. Hyperhomocysteinemia is associated with increased oxidative stress, and in the pathogenesis of diabetic retinopathy, oxidative stress-mitochondrial dysfunction precedes the development of histopathology characteristic of diabetic retinopathy. Furthermore, homocysteine biosynthesis from methionine forms S-adenosyl methionine (SAM), and SAM is a co-substrate of DNA methylation. In diabetes, DNA methylation machinery is activated, and mitochondrial DNA (mtDNA) and several genes associated with mitochondrial homeostasis undergo epigenetic modifications. Consequently, high homocysteine, by further affecting methylation of mtDNA and that of genes associated with mtDNA damage and biogenesis, does not give any break to the already damaged mitochondria, and the vicious cycle of free radicals continues. Thus, supplementation of sensible glycemic control with therapies targeting hyperhomocysteinemia could be valuable for diabetic patients to prevent/slow down the development of this sight-threatening disease.
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Yuan R, Yang M, Fan W, Lan J, Zhou YG. Paired Immunoglobulin-like Receptor B Inhibition in Müller Cells Promotes Neurite Regeneration After Retinal Ganglion Cell Injury in vitro. Neurosci Bull 2020; 36:972-984. [PMID: 32445021 DOI: 10.1007/s12264-020-00510-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/31/2020] [Indexed: 02/07/2023] Open
Abstract
In the central nervous system (CNS), three types of myelin-associated inhibitors (MAIs) have major inhibitory effects on nerve regeneration. They include Nogo-A, myelin-associated glycoprotein, and oligodendrocyte-myelin glycoprotein. MAIs possess two co-receptors, Nogo receptor (NgR) and paired immunoglobulin-like receptor B (PirB). Previous studies have confirmed that the inhibition of NgR only results in a modest increase in regeneration in the CNS; however, the inhibitory effects of PirB with regard to nerve regeneration after binding to MAIs remain controversial. In this study, we demonstrated that PirB is expressed in primary cultures of retinal ganglion cells (RGCs), and the inhibitory effects of the three MAIs on the growth of RGC neurites are not significantly decreased after direct PirB knockdown using adenovirus PirB shRNA. Interestingly, we found that retinal Müller cells expressed PirB and that its knockdown enhanced the regeneration of co-cultured RGC neurites. PirB knockdown also activated the JAK/Stat3 signaling pathway in Müller cells and upregulated ciliary neurotrophic factor levels. These findings indicate that PirB plays a novel role in retinal Müller cells and that its action in these cells may indirectly affect the growth of RGC neurites. The results also reveal that PirB in Müller cells affects RGC neurite regeneration. Our findings provide a novel basis for the use of PirB as a target molecule to promote nerve regeneration.
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Affiliation(s)
- Rongdi Yuan
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China.,The Molecular Biology Centre, State Key Laboratory of Trauma, Burn and Combined Injury, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Mei Yang
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Wei Fan
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Jian Lan
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Yuan-Guo Zhou
- The Molecular Biology Centre, State Key Laboratory of Trauma, Burn and Combined Injury, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, 400042, China.
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Xiao H, Wang J, Saul A, Smith SB. Comparison of Neuroprotective Effects of Monomethylfumarate to the Sigma 1 Receptor Ligand (+)-Pentazocine in a Murine Model of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2020; 61:5. [PMID: 32150247 PMCID: PMC7401726 DOI: 10.1167/iovs.61.3.5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/24/2019] [Indexed: 12/20/2022] Open
Abstract
Purpose Activating the cell survival modulator sigma 1 receptor (Sig1R) delays cone photoreceptor cell loss in Pde6βrd10/J (rd10) mice, a model of retinitis pigmentosa. Beneficial effects are abrogated in rd10 mice lacking NRF2, implicating NRF2 as essential to Sig1R-mediated cone neuroprotection. Here we asked whether activation of NRF2 alone is sufficient to rescue cones in rd10 mice. Methods Expression of antioxidant genes was evaluated in 661W cells and in mouse retinas after treatment with monomethylfumarate (MMF), a potent NRF2 activator. Rd10 mice were administered MMF (50 mg/kg) or the Sig1R ligand (+)-pentazocine (PTZ; 0.5 mg/kg) intraperitoneally (every other day, P14-42). Mice were evaluated for visual acuity (optokinetic tracking response), retinal function (electroretinography) and architecture (SD-OCT); histologic retinal sections were evaluated morphometrically. Results MMF treatment increased Nrf2, Nqo1, Cat, Sod1, and Hmox1 expression in vitro and in vivo. Visual acuity of (+)-PTZ-treated rd10 mice was similar to wild-type mice; however, MMF treatment did not alter acuity compared with nontreated rd10 mice. Cone electroretinography b-wave amplitudes were greater in PTZ-treated than nontreated or MMF-treated rd10 mice. SD-OCT assessment of retinal thickness was greater in (+)-PTZ-treated mice versus nontreated or MMF-treated rd10 mice. Morphometric assessment of the outer nuclear layer revealed approximately 18 cells/100 µm retinal length in (+)-PTZ-treated rd10 mice, but only approximately 10 to 12 cells/100 µm in MMF-treated and nontreated rd10 retinas. Conclusions Activation of NRF2 using MMF, at least at our dosing regimen, is insufficient to attenuate catastrophic photoreceptor damage characteristic of rd10 mice. The data prompt investigation of additional mechanisms involved in Sig1R-mediated retinal neuroprotection.
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Affiliation(s)
- Haiyan Xiao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia,United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia,United States
| | - Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia,United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia,United States
| | - Alan Saul
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia,United States
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia,United States
| | - Sylvia B. Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia,United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia,United States
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia,United States
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Role of Arginase 2 in Murine Retinopathy Associated with Western Diet-Induced Obesity. J Clin Med 2020; 9:jcm9020317. [PMID: 31979105 PMCID: PMC7073940 DOI: 10.3390/jcm9020317] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/08/2020] [Accepted: 01/18/2020] [Indexed: 12/19/2022] Open
Abstract
Western diet-induced obesity is linked to the development of metabolic dysfunctions, including type 2 diabetes and complications that include retinopathy, a leading cause of blindness. Aberrant activation of the inflammasome cascade leads to the progression of obesity-induced pathologies. Our lab showed the critical role of arginase 2 (A2), the mitochondrial isoform of this ureahydrolase, in obesity-induced metabolic dysfunction and inflammation. A2 deletion also has been shown to be protective against retinal inflammation in models of ischemic retinopathy and multiple sclerosis. We investigated the effect of A2 deletion on western diet-induced retinopathy. Wild-type mice fed a high-fat, high-sucrose western diet for 16 weeks exhibited elevated retinal expression of A2, markers of the inflammasome pathway, oxidative stress, and activation of microglia/macrophages. Western diet feeding induced exaggerated retinal light responses without affecting visual acuity or retinal morphology. These effects were reduced or absent in mice with global A2 deletion. Exposure of retinal endothelial cells to palmitate and high glucose, a mimic of the obese state, increased expression of A2 and inflammatory mediators and induced cell death. These effects, except for A2, were prevented by pretreatment with an arginase inhibitor. Collectively, our study demonstrated a substantial role of A2 in early manifestations of diabetic retinopathy.
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Khaled ML, Bykhovskaya Y, Gu C, Liu A, Drewry MD, Chen Z, Mysona BA, Parker E, McNabb RP, Yu H, Lu X, Wang J, Li X, Al-Muammar A, Rotter JI, Porter LF, Estes A, Watsky MA, Smith SB, Xu H, Abu-Amero KK, Kuo A, Shears SB, Rabinowitz YS, Liu Y. PPIP5K2 and PCSK1 are Candidate Genetic Contributors to Familial Keratoconus. Sci Rep 2019; 9:19406. [PMID: 31852976 PMCID: PMC6920454 DOI: 10.1038/s41598-019-55866-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/02/2019] [Indexed: 12/30/2022] Open
Abstract
Keratoconus (KC) is the most common corneal ectatic disorder affecting >300,000 people in the US. KC normally has its onset in adolescence, progressively worsening through the third to fourth decades of life. KC patients report significant impaired vision-related quality of life. Genetic factors play an important role in KC pathogenesis. To identify novel genes in familial KC patients, we performed whole exome and genome sequencing in a four-generation family. We identified potential variants in the PPIP5K2 and PCSK1 genes. Using in vitro cellular model and in vivo gene-trap mouse model, we found critical evidence to support the role of PPIP5K2 in normal corneal function and KC pathogenesis. The gene-trap mouse showed irregular corneal surfaces and pathological corneal thinning resembling KC. For the first time, we have integrated corneal tomography and pachymetry mapping into characterization of mouse corneal phenotypes which could be widely implemented in basic and translational research for KC diagnosis and therapy in the future.
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Affiliation(s)
- Mariam Lofty Khaled
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Yelena Bykhovskaya
- Department of Surgery and Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Chunfang Gu
- Inositol Signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Alice Liu
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Michelle D Drewry
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Zhong Chen
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Barbara A Mysona
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Emily Parker
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Ryan P McNabb
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Hongfang Yu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Xiaowen Lu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Jing Wang
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Xiaohui Li
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute and Department of Pediatrics and Medicine at Harbor-UCLA, Torrance, CA, USA
| | - Abdulrahman Al-Muammar
- Department of Ophthalmology, Glaucoma Research Chair, King Saud University, Riyadh, Saudi Arabia
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute and Department of Pediatrics and Medicine at Harbor-UCLA, Torrance, CA, USA
| | - Louise F Porter
- Department of Eye and Vision Science, University of Liverpool, and St Paul's Eye Unit, Royal Liverpool Hospital, Liverpool, UK
| | - Amy Estes
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
- Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - Mitchell A Watsky
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
- Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - Hongyan Xu
- Department of Population Health Science, Augusta University, Augusta, GA, USA
| | - Khaled K Abu-Amero
- Department of Ophthalmology, Glaucoma Research Chair, King Saud University, Riyadh, Saudi Arabia
| | - Anthony Kuo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Stephen B Shears
- Inositol Signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Yaron S Rabinowitz
- Department of Surgery and Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA.
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.
- Center for Biotechnology and Genomic Medicine, Augusta University, Augusta, GA, USA.
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Ammal Kaidery N, Ahuja M, Thomas B. Crosstalk between Nrf2 signaling and mitochondrial function in Parkinson's disease. Mol Cell Neurosci 2019; 101:103413. [PMID: 31644952 DOI: 10.1016/j.mcn.2019.103413] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 12/12/2022] Open
Abstract
Search for a definitive cure for neurodegenerative disorders like Parkinson's disease (PD) has met with little success. Mitochondrial dysfunction and elevated oxidative stress precede characteristic loss of dopamine-producing neurons from the midbrain in PD. The majority of PD cases are classified as sporadic (sPD) with an unknown etiology, whereas mutations in a handful of genes cause monogenic form called familial (fPD). Both sPD and fPD is characterized by proteinopathy and mitochondrial dysfunction leading to increased oxidative stress. These pathophysiological mechanisms create a vicious cycle feeding into each other, ultimately tipping the neurons to its demise. Effect of iron accumulation and dopamine oxidation adds an additional dimension to mitochondrial oxidative stress and apoptotic pathways affected. Nrf2 is a redox-sensitive transcription factor which regulates basal as well as inducible expression of antioxidant enzymes and proteins involved in xenobiotic detoxification. Recent advances, however, shows a multifaceted role for Nrf2 in the regulation of genes connected with inflammatory response, metabolic pathways, protein homeostasis, iron management, and mitochondrial bioenergetics. Here we review the role of mitochondria and oxidative stress in the PD etiology and the potential crosstalk between Nrf2 signaling and mitochondrial function in PD. We also make a case for the development of therapeutics that safely activates Nrf2 pathway in halting the progression of neurodegeneration in PD patients.
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Affiliation(s)
- Navneet Ammal Kaidery
- Darby Research Institute, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, United States of America
| | - Manuj Ahuja
- Darby Research Institute, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, United States of America
| | - Bobby Thomas
- Darby Research Institute, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, United States of America; Department of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425, United States of America.
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Wang J, Saul A, Smith SB. Activation of Sigma 1 Receptor Extends Survival of Cones and Improves Visual Acuity in a Murine Model of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2019; 60:4397-4407. [PMID: 31639826 PMCID: PMC6808049 DOI: 10.1167/iovs.19-27709] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 08/21/2019] [Indexed: 01/02/2023] Open
Abstract
Purpose Retinitis pigmentosa (RP), a retinal photoreceptor degeneration, typically affects rod function and subsequently cones. Activation of sigma 1 receptor (Sig1R) has been shown to preserve cone function through 6 weeks in the rd10 mouse model of RP, when mice were treated systemically with the Sig1R ligand (+)-pentazocine (PTZ). This study determined the extent to which cone function is preserved in rd10 mice when Sig1R is activated. Methods Rd10 mice were administered (+)-PTZ (alternate days beginning at postnatal day [P]14) over a period of 180 days. Mouse visual function and structure were measured in vivo using optokinetic tracking response, scotopic and photopic electroretinography plus photopic assessment using "natural" noise stimuli, and optical coherence tomography (OCT). Immunofluorescent methods were used to detect cones in retinal cryosections. Results Visual acuity was maintained in rd10(+)-PTZ-treated mice through P56, whereas rd10 nontreated mice showed marked decline by P28. Cone responses were detected in (+)-PTZ-treated mice through P60, which were more robust when tested with natural noise stimuli; cone responses were minimal in nontreated rd10 mice. OCT revealed significantly thicker retinas in (+)-PTZ-treated rd10 mice through P60 compared to nontreated mice. Cones were detected by immunofluorescence in (+)-PTZ-treated rd10 retinas through P120. Conclusions The extent to which cone rescue could be sustained in (+)-PTZ-treated rd10 mice was evaluated comprehensively, showing that activation of Sig1R is associated with prolonged visual acuity, extended detection of cone function, and detection of cones in retinal histologic sections. The data reflect promising long-term neuroprotection when Sig1R is activated.
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Affiliation(s)
- Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia, United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Alan Saul
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, Georgia, United States
| | - Sylvia B. Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia, United States
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, Georgia, United States
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