1
|
Yanardag S, Rhodes S, Saravanan T, Guan T, Ramamurthy V. Prominin 1 is crucial for the early development of photoreceptor outer segments. Sci Rep 2024; 14:10498. [PMID: 38714794 PMCID: PMC11076519 DOI: 10.1038/s41598-024-60989-5] [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: 03/12/2024] [Accepted: 04/30/2024] [Indexed: 05/10/2024] Open
Abstract
Prominin 1 (PROM1) is a pentaspan transmembrane glycoprotein localized on the nascent photoreceptor discs. Mutations in PROM1 are linked to various retinal diseases. In this study, we assessed the role of PROM1 in photoreceptor biology and physiology using the PROM1 knockout murine model (rd19). Our study found that PROM1 is essential for vision and photoreceptor development. We found an early reduction in photoreceptor response beginning at post-natal day 12 (P12) before eye opening in the absence of PROM1 with no apparent loss in photoreceptor cells. However, at this stage, we observed an increased glial cell activation, indicative of cell damage. Contrary to our expectations, dark rearing did not mitigate photoreceptor degeneration or vision loss in PROM1 knockout mice. In addition to physiological defects seen in PROM1 knockout mice, ultrastructural analysis revealed malformed outer segments characterized by whorl-like continuous membranes instead of stacked disks. In parallel to the reduced rod response at P12, proteomics revealed a significant reduction in the levels of protocadherin, a known interactor of PROM1, and rod photoreceptor outer segment proteins, including rhodopsin. Overall, our results underscore the indispensable role of PROM1 in photoreceptor development and maintenance of healthy vision.
Collapse
Affiliation(s)
- Sila Yanardag
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA
| | - Scott Rhodes
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA
| | - Thamaraiselvi Saravanan
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA
| | - Tongju Guan
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA
| | - Visvanathan Ramamurthy
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV, USA.
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, USA.
| |
Collapse
|
2
|
Ung TT, Starr CR, Zhylkibayev A, Saltykova I, Gorbatyuk M. Development of TRIB3-Based Therapy as a Gene-Independent Approach to Treat Retinal Degenerative Disorders. Int J Mol Sci 2024; 25:4716. [PMID: 38731938 PMCID: PMC11083933 DOI: 10.3390/ijms25094716] [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: 03/11/2024] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Inherited retinal degeneration (RD) constitutes a heterogeneous group of genetic retinal degenerative disorders. The molecular mechanisms underlying RD encompass a diverse spectrum of cellular signaling, with the unfolded protein response (UPR) identified as a common signaling pathway chronically activated in degenerating retinas. TRIB3 has been recognized as a key mediator of the PERK UPR arm, influencing various metabolic pathways, such as insulin signaling, lipid metabolism, and glucose homeostasis, by acting as an AKT pseudokinase that prevents the activation of the AKT → mTOR axis. This study aimed to develop a gene-independent approach targeting the UPR TRIB3 mediator previously tested by our group using a genetic approach in mice with RD. The goal was to validate a therapeutic approach targeting TRIB3 interactomes through the pharmacological targeting of EGFR-TRIB3 and delivering cell-penetrating peptides targeting TRIB3 → AKT. The study employed rd10 and P23H RHO mice, with afatinib treatment conducted in p15 rd10 mice through daily intraperitoneal injections. P15 P23H RHO mice received intraocular injections of cell-penetrating peptides twice at a 2-week interval. Our study revealed that both strategies successfully targeted TRIB3 interactomes, leading to an improvement in scotopic A- and B-wave ERG recordings. Additionally, the afatinib-treated mice manifested enhanced photopic ERG amplitudes accompanied by a delay in photoreceptor cell loss. The treated rd10 retinas also showed increased PDE6β and RHO staining, along with an elevation in total PDE activity in the retinas. Consequently, our study demonstrated the feasibility of a gene-independent strategy to target common signaling in degenerating retinas by employing a TRIB3-based therapeutic approach that delays retinal function and photoreceptor cell loss in two RD models.
Collapse
Affiliation(s)
| | | | | | | | - Marina Gorbatyuk
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL 35233, USA; (T.T.U.); (C.R.S.); (A.Z.)
| |
Collapse
|
3
|
Wu Y, Wan X, Zhao D, Chen X, Wang Y, Tang X, Li J, Li S, Sun X, Bi C, Zhang X. AAV-mediated base-editing therapy ameliorates the disease phenotypes in a mouse model of retinitis pigmentosa. Nat Commun 2023; 14:4923. [PMID: 37582961 PMCID: PMC10427680 DOI: 10.1038/s41467-023-40655-6] [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: 10/08/2022] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Base editing technology is an ideal solution for treating pathogenic single-nucleotide variations (SNVs). No gene editing therapy has yet been approved for eye diseases, such as retinitis pigmentosa (RP). Here, we show, in the rd10 mouse model, which carries an SNV identified as an RP-causing mutation in human patients, that subretinal delivery of an optimized dual adeno-associated virus system containing the adenine base editor corrects the pathogenic SNV in the neuroretina with up to 49% efficiency. Light microscopy showed that a thick and robust outer nuclear layer (photoreceptors) was preserved in the treated area compared with the thin, degenerated outer nuclear layer without treatment. Substantial electroretinogram signals were detected in treated rd10 eyes, whereas control treated eyes showed minimal signals. The water maze experiment showed that the treatment substantially improved vision-guided behavior. Together, we construct and validate a translational therapeutic solution for the treatment of RP in humans. Our findings might accelerate the development of base-editing based gene therapies.
Collapse
Affiliation(s)
- Yidong Wu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
| | - Xiaoling Wan
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- National Clinical Research Center for Eye Diseases, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China.
| | - Dongdong Zhao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xuxu Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Yujie Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xinxin Tang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Ju Li
- College of Life Science, Tianjin Normal University, Tianjin, China
| | - Siwei Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- National Clinical Research Center for Eye Diseases, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China.
| | - Changhao Bi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, China.
| | - Xueli Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, China.
| |
Collapse
|
4
|
Munezero D, Aliff H, Salido E, Saravanan T, Sanzhaeva U, Guan T, Ramamurthy V. HSP90α is needed for the survival of rod photoreceptors and regulates the expression of rod PDE6 subunits. J Biol Chem 2023; 299:104809. [PMID: 37172722 PMCID: PMC10250166 DOI: 10.1016/j.jbc.2023.104809] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
Heat shock protein 90 (HSP90) is an abundant molecular chaperone that regulates the stability of a small set of proteins essential in various cellular pathways. Cytosolic HSP90 has two closely related paralogs: HSP90α and HSP90β. Due to the structural and sequence similarities of cytosolic HSP90 paralogs, identifying the unique functions and substrates in the cell remains challenging. In this article, we assessed the role of HSP90α in the retina using a novel HSP90α murine knockout model. Our findings show that HSP90α is essential for rod photoreceptor function but was dispensable in cone photoreceptors. In the absence of HSP90α, photoreceptors developed normally. We observed rod dysfunction in HSP90α knockout at 2 months with the accumulation of vacuolar structures, apoptotic nuclei, and abnormalities in the outer segments. The decline in rod function was accompanied by progressive degeneration of rod photoreceptors that was complete at 6 months. The deterioration in cone function and health was a "bystander effect" that followed the degeneration of rods. Tandem mass tag proteomics showed that HSP90α regulates the expression levels of <1% of the retinal proteome. More importantly, HSP90α was vital in maintaining rod PDE6 and AIPL1 cochaperone levels in rod photoreceptor cells. Interestingly, cone PDE6 levels were unaffected. The robust expression of HSP90β paralog in cones likely compensates for the loss of HSP90α. Overall, our study demonstrated the critical need for HSP90α chaperone in the maintenance of rod photoreceptors and showed potential substrates regulated by HSP90α in the retina.
Collapse
Affiliation(s)
- Daniella Munezero
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Hunter Aliff
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Ezequiel Salido
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Thamaraiselvi Saravanan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Urikhan Sanzhaeva
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Tongju Guan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Visvanathan Ramamurthy
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA.
| |
Collapse
|
5
|
Song DJ, Bao XL, Fan B, Li GY. Mechanism of Cone Degeneration in Retinitis Pigmentosa. Cell Mol Neurobiol 2023; 43:1037-1048. [PMID: 35792991 DOI: 10.1007/s10571-022-01243-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
Retinitis pigmentosa (RP) is a group of genetic disorders resulting in inherited blindness due to the degeneration of rod and cone photoreceptors. The various mechanisms underlying rod degeneration primarily rely on genetic mutations, leading to night blindness initially. Cones gradually degenerate after rods are almost eliminated, resulting in varying degrees of visual disability and blindness. The mechanism of cone degeneration remains unclear. An understanding of the mechanisms underlying cone degeneration in RP, a highly heterogeneous disease, is essential to develop novel treatments of RP. Herein, we review recent advancements in the five hypotheses of cone degeneration, including oxidative stress, trophic factors, metabolic stress, light damage, and inflammation activation. We also discuss the connection among these theories to provide a better understanding of secondary cone degeneration in RP. Five current mechanisms of cone degenerations in RP Interactions among different pathways are involved in RP.
Collapse
Affiliation(s)
- De-Juan Song
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Xiao-Li Bao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Bin Fan
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Guang-Yu Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China.
| |
Collapse
|
6
|
Lu C, Li S, Jin M. Rapamycin Inhibits Light-Induced Necrosome Activation Occurring in Wild-Type, but not RPE65-Null, Mouse Retina. Invest Ophthalmol Vis Sci 2022; 63:19. [PMID: 36534385 PMCID: PMC9769341 DOI: 10.1167/iovs.63.13.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose Both photodamage and aberrant visual cycle contribute to disease progress of many retinal degenerative disorders, whereas the signaling pathways causing photoreceptor death remain unclear. Here we investigated the effects of intense photo-stress on (1) necrosome activation in wild-type and RPE65-null mice, (2) interaction of p62/Sequestosome-1 with the necrosome proteins, and (3) the effects of rapamycin on photodamage-induced necrosome activation and retinal degeneration in wild-type mice. Methods Dark-adapted rd12 mice and 129S2/Sv mice with or without rapamycin treatment were exposed to 15,000 lux light for different times. Expression levels and subcellular localization of proteins were determined through immunoblot and immunohistochemical analyses. Cone sheaths were stained with peanut agglutinin. Correlation between photoreceptor degeneration and receptor-interacting protein kinase-1 (RIPK1) expression was assessed with Spearman's correlation analysis. Protein-protein interaction was analyzed by immunoprecipitation. Results Intense light caused rod and cone degeneration accompanied by a significant increase in RIPK1-RIPK3 expressions, mixed lineage kinase domain-like protein phosphorylation, damage-associated molecular patterns protein release, and inflammatory responses in wild-type mouse retina. The same intense light did not induce the necrosome activation in rd12 retina, but it did in rd12 mice that received 9-cis-retinal supply. RIPK1 expression levels are positively correlated with the degrees of rod and cone degeneration. Photodamage upregulated expression and interaction of the p62 autophagosome cargo protein with the necrosome proteins, whereas rapamycin treatment attenuated the light-induced necrosome activation and photoreceptor degeneration. Conclusions Necrosome activation contributed to photodamage-induced rod and cone degeneration. The visual cycle and autophagy are the important therapeutic targets to alleviate light-induced retinal necroptosis.
Collapse
Affiliation(s)
- Chunfeng Lu
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana, United States
| | - Songhua Li
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana, United States
| | - Minghao Jin
- Neuroscience Center of Excellence, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana, United States,Department of Ophthalmology, Louisiana State University School of Medicine, LSU Health New Orleans, New Orleans, Louisiana, United States
| |
Collapse
|
7
|
Su T, Liang L, Zhang L, Wang J, Chen L, Su C, Cao J, Yu Q, Deng S, Chan HF, Tang S, Guo Y, Chen J. Retinal organoids and microfluidic chip-based approaches to explore the retinitis pigmentosa with USH2A mutations. Front Bioeng Biotechnol 2022; 10:939774. [PMID: 36185441 PMCID: PMC9524156 DOI: 10.3389/fbioe.2022.939774] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/23/2022] [Indexed: 11/19/2022] Open
Abstract
Retinitis pigmentosa (RP) is a leading cause of vision impairment and blindness worldwide, with limited medical treatment options. USH2A mutations are one of the most common causes of non-syndromic RP. In this study, we developed retinal organoids (ROs) and retinal pigment epithelium (RPE) cells from induced pluripotent stem cells (iPSCs) of RP patient to establish a sustainable in vitro RP disease model. RT-qPCR, western blot, and immunofluorescent staining assessments showed that USH2A mutations induced apoptosis of iPSCs and ROs, and deficiency of the extracellular matrix (ECM) components. Transcriptomics and proteomics findings suggested that abnormal ECM-receptor interactions could result in apoptosis of ROs with USH2A mutations via the PI3K-Akt pathway. To optimize the culture conditions of ROs, we fabricated a microfluidic chip to co-culture the ROs with RPE cells. Our results showed that this perfusion system could efficiently improve the survival rate of ROs. Further, ECM components such as laminin and collagen IV of ROs in the RP group were upregulated compared with those maintained in static culture. These findings illustrate the potential of microfluidic chip combined with ROs technology in disease modelling for RP.
Collapse
Affiliation(s)
- Ting Su
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Liying Liang
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Lan Zhang
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Jianing Wang
- Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou, China
| | - Luyin Chen
- Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou, China
| | - Caiying Su
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Jixing Cao
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Quan Yu
- Centric Laboratory, Medical College, Jinan University, Guangzhou, China
| | - Shuai Deng
- Institute for Tissue Engineering and Regenerative Medicine, Chinese University of Hong Kong, Hong Kong, China
- Key Laboratory for Regenerative Medicine of the Ministry of Education of China, Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Hon Fai Chan
- Institute for Tissue Engineering and Regenerative Medicine, Chinese University of Hong Kong, Hong Kong, China
- Key Laboratory for Regenerative Medicine of the Ministry of Education of China, Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | | | - Yonglong Guo
- Department of Ophthalmology, First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- *Correspondence: Jiansu Chen, ; Yonglong Guo,
| | - Jiansu Chen
- Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou, China
- Aier Eye Institute, Changsha, China
- Institute of Ophthalmology, Medical College, Jinan University, Guangzhou, China
- *Correspondence: Jiansu Chen, ; Yonglong Guo,
| |
Collapse
|
8
|
Weh E, Scott K, Wubben TJ, Besirli CG. Dark-reared rd10 mice experience rapid photoreceptor degeneration with short exposure to room-light during in vivo retinal imaging. Exp Eye Res 2022; 215:108913. [PMID: 34965404 PMCID: PMC8923962 DOI: 10.1016/j.exer.2021.108913] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 02/03/2023]
Abstract
Inherited retinal diseases (IRDs) are a collection of rare genetic conditions, which can lead to complete blindness. A large number of causative genes have been identified for IRDs and while some success has been achieved with gene therapies, they are limited in scope to each individual gene and/or the specific mutation harbored by each patient with an IRD. Multiple studies are underway to elucidate common underlying mechanisms contributing to photoreceptor (PR) loss and to design gene-agnostic, pan-disease therapeutics. The rd10 mouse, which recapitulates slow degeneration of PRs, is an in vivo IRD model used commonly by vision researchers. Light deprivation by rearing animals in complete darkness significantly delays PR death in rd10 mice, subsequently increasing the time window for in vivo studies investigating neuroprotective strategies. Longitudinal in vivo retinal imaging following the same rd10 mice over time is a potential solution for reducing the number of animals required to complete a study. We describe a previously unreported phenotype in the dark-reared rd10 model that is characterized by dramatic PR degeneration following brief exposure to low-intensity light. This exquisite light sensitivity precludes the use of longitudinal studies employing in vivo imaging or other functional assessment requiring room light in rd10 mice and highlights the importance of closely following animal models of IRD to determine any deviations from the expected degeneration curve during routine experimentation.
Collapse
Affiliation(s)
| | | | | | - Cagri G. Besirli
- Corresponding Author, please direct all correspondence to: Cagri Besirli, 1000 Wall St., Ann Arbor, MI 48105, 734-232-8404,
| |
Collapse
|
9
|
Jiang K, Fairless E, Kanda A, Gotoh N, Cogliati T, Li T, Swaroop A. Divergent Effects of HSP70 Overexpression in Photoreceptors During Inherited Retinal Degeneration. Invest Ophthalmol Vis Sci 2021; 61:25. [PMID: 33107904 PMCID: PMC7594617 DOI: 10.1167/iovs.61.12.25] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose Disruption of proteostasis is a key event in many neurodegenerative diseases. Heat shock proteins (HSPs) participate in multiple functions associated with intracellular transport and proteostasis. We evaluated the effect of augmented HSP70 expression in mutant photoreceptors of mouse retinal degeneration models to test the hypothesis that failure to sustain HSP70 expression contributes to photoreceptor cell death. Methods We examined HSP70 expression in retinas of wild-type and mutant mice by RNA and protein analysis. A transgenic mouse line, TgCrx-Hspa1a-Flag, was generated to express FLAG-tagged full-length HSP70 protein under control of a 2.3 kb mouse Crx promoter. This line was crossed to three distinct retinal degeneration mouse models. Retinal structure and function were evaluated by histology, immunohistochemistry, and electroretinography. Results In seven different mouse models of retinal degeneration, we detected transient elevation of endogenous HSP70 expression at early stages, followed by a dramatic reduction as cell death ensues, suggesting an initial adaptive response to cellular stress. Augmented expression of HSP70 in RHOT17M mice, in which mutant rhodopsin is misfolded, marginally improved photoreceptor survival, whereas elevated HSP70 led to more severe retinal degeneration in rd10 mutants that produce a partially functional PDE6B. In Rpgrip1−/− mice that display a ciliary defect, higher HSP70 had no impact on photoreceptor survival or function. Conclusions HSP70 overexpression has divergent effects in photoreceptors determined, at least in part, by the nature of the mutant protein each model carries. Additional investigations on HSP pathways and associated chaperone networks in photoreceptors are needed before designing therapeutic strategies targeting proteostasis.
Collapse
Affiliation(s)
- Ke Jiang
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Elizabeth Fairless
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Atsuhiro Kanda
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Norimoto Gotoh
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiziana Cogliati
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiansen Li
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Anand Swaroop
- Neurobiology, Neurodegeneration, and Repair Laboratory (NNRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| |
Collapse
|
10
|
Yang P, Lockard R, Titus H, Hiblar J, Weller K, Wafai D, Weleber RG, Duvoisin RM, Morgans CW, Pennesi ME. Suppression of cGMP-Dependent Photoreceptor Cytotoxicity With Mycophenolate Is Neuroprotective in Murine Models of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2021; 61:25. [PMID: 32785677 PMCID: PMC7441375 DOI: 10.1167/iovs.61.10.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose To determine the effect of mycophenolate mofetil (MMF) on retinal degeneration on two mouse models of retinitis pigmentosa. Methods Intraperitoneal injections of MMF were administered daily in rd10 and c57 mice starting at postoperative day 12 (P12) and rd1 mice starting at P8. The effect of MMF was assessed with optical coherence tomography, immunohistochemistry, electroretinography, and OptoMotry. Whole retinal cyclic guanosine monophosphate (cGMP) and mycophenolic acid levels were quantified with mass spectrometry. Photoreceptor cGMP cytotoxicity was evaluated with cell counts of cGMP immunostaining. Results MMF treatment significantly delays the onset of retinal degeneration and cGMP-dependent photoreceptor cytotoxicity in rd10 and rd1 mice, albeit a more modest effect in the latter. In rd10 mice, treatment with MMF showed robust preservation of the photoreceptors up to P22 with associated suppression of cGMP immunostaining and microglial activation; The neuroprotective effect diminished after P22, but outer retinal thickness was still significantly thicker by P35 and OptoMotry response was significantly better up to P60. Whereas cGMP immunostaining of the photoreceptors were present in rd10 and rd1 mice, hyperphysiological whole retinal cGMP levels were observed only in rd1 mice. Conclusions Early treatment with MMF confers potent neuroprotection in two animal models of RP by suppressing the cGMP-dependent common pathway for photoreceptor cell death. The neuroprotective effect of MMF on cGMP-dependent cytotoxicity occurs independently of the presence of hyperphysiological whole retinal cGMP levels. Thus our data suggest that MMF may be an important new class of neuroprotective agent that could be useful in the treatment of patients with RP.
Collapse
Affiliation(s)
- Paul Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Rachel Lockard
- School of Medicine, Oregon Health & Science University, Portland, Oregon, United States
| | - Hope Titus
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Jordan Hiblar
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Kyle Weller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Dahlia Wafai
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Robert M Duvoisin
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Catherine W Morgans
- Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| |
Collapse
|
11
|
Kutsyr O, Sánchez-Sáez X, Martínez-Gil N, de Juan E, Lax P, Maneu V, Cuenca N. Gradual Increase in Environmental Light Intensity Induces Oxidative Stress and Inflammation and Accelerates Retinal Neurodegeneration. Invest Ophthalmol Vis Sci 2021; 61:1. [PMID: 32744596 PMCID: PMC7441298 DOI: 10.1167/iovs.61.10.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a blinding neurodegenerative disease of the retina that can be affected by many factors. The present study aimed to analyze the effect of different environmental light intensities in rd10 mice retina. Methods C57BL/6J and rd10 mice were bred and housed under three different environmental light intensities: scotopic (5 lux), mesopic (50 lux), and photopic (300 lux). Visual function was studied using electroretinography and optomotor testing. The structural and morphological integrity of the retinas was evaluated by optical coherence tomography imaging and immunohistochemistry. Additionally, inflammatory processes and oxidative stress markers were analyzed by flow cytometry and western blotting. Results When the environmental light intensity was higher, retinal function decreased in rd10 mice and was accompanied by light-dependent photoreceptor loss, followed by morphological alterations, and synaptic connectivity loss. Moreover, light-dependent retinal degeneration was accompanied by an increased number of inflammatory cells, which became more activated and phagocytic, and by an exacerbated reactive gliosis. Furthermore, light-dependent increment in oxidative stress markers in rd10 mice retina pointed to a possible mechanism for light-induced photoreceptor degeneration. Conclusions An increase in rd10 mice housing light intensity accelerates retinal degeneration, activating cell death, oxidative stress pathways, and inflammatory cells. Lighting intensity is a key factor in the progression of retinal degeneration, and standardized lighting conditions are advisable for proper analysis and interpretation of experimental results from RP animal models, and specifically from rd10 mice. Also, it can be hypothesized that light protection could be an option to slow down retinal degeneration in some cases of RP.
Collapse
|