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Cvekl A, Vijg J. Aging of the eye: Lessons from cataracts and age-related macular degeneration. Ageing Res Rev 2024; 99:102407. [PMID: 38977082 DOI: 10.1016/j.arr.2024.102407] [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: 03/11/2024] [Revised: 06/18/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024]
Abstract
Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease.
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Affiliation(s)
- Ales Cvekl
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Jan Vijg
- Departments of Genetics and Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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2
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Akula M, McNamee SM, Love Z, Nasraty N, Chan NPM, Whalen M, Avola MO, Olivares AM, Leehy BD, Jelcick AS, Singh P, Upadhyay AK, Chen DF, Haider NB. Retinoic acid related orphan receptor α is a genetic modifier that rescues retinal degeneration in a mouse model of Stargardt disease and Dry AMD. Gene Ther 2024; 31:413-421. [PMID: 38755404 PMCID: PMC11257945 DOI: 10.1038/s41434-024-00455-z] [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: 08/30/2023] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024]
Abstract
Degeneration of the macula is associated with several overlapping diseases including age-related macular degeneration (AMD) and Stargardt Disease (STGD). Mutations in ATP Binding Cassette Subfamily A Member 4 (ABCA4) are associated with late-onset dry AMD and early-onset STGD. Additionally, both forms of macular degeneration exhibit deposition of subretinal material and photoreceptor degeneration. Retinoic acid related orphan receptor α (RORA) regulates the AMD inflammation pathway that includes ABCA4, CD59, C3 and C5. In this translational study, we examined the efficacy of RORA at attenuating retinal degeneration and improving the inflammatory response in Abca4 knockout (Abca4-/-) mice. AAV5-hRORA-treated mice showed reduced deposits, restored CD59 expression and attenuated amyloid precursor protein (APP) expression compared with untreated eyes. This molecular rescue correlated with statistically significant improvement in photoreceptor function. This is the first study evaluating the impact of RORA modifier gene therapy on rescuing retinal degeneration. Our studies demonstrate efficacy of RORA in improving STGD and dry AMD-like disease.
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Affiliation(s)
- M Akula
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - S M McNamee
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Z Love
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - N Nasraty
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - N P M Chan
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - M Whalen
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - M O Avola
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - A M Olivares
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - B D Leehy
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - A S Jelcick
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - P Singh
- Ocugen, Inc., Malvern, PA, USA
| | | | - D F Chen
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - N B Haider
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
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Tan LX, Oertel FC, Cheng A, Cobigo Y, Keihani A, Bennett DJ, Abdelhak A, Montes SC, Chapman M, Chen RY, Cordano C, Ward ME, Casaletto K, Kramer JH, Rosen HJ, Boxer A, Miller BL, Green AJ, Elahi FM, Lakkaraju A. Targeting complement C3a receptor resolves mitochondrial hyperfusion and subretinal microglial activation in progranulin-deficient frontotemporal dementia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.595206. [PMID: 38854134 PMCID: PMC11160746 DOI: 10.1101/2024.05.29.595206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Mutations in progranulin ( GRN ) cause frontotemporal dementia ( GRN -FTD) due to deficiency of the pleiotropic protein progranulin. GRN -FTD exhibits diverse pathologies including lysosome dysfunction, lipofuscinosis, microgliosis, and neuroinflammation. Yet, how progranulin loss causes disease remains unresolved. Here, we report that non-invasive retinal imaging of GRN -FTD patients revealed deficits in photoreceptors and the retinal pigment epithelium (RPE) that correlate with cognitive decline. Likewise, Grn -/- mice exhibit early RPE dysfunction, microglial activation, and subsequent photoreceptor loss. Super-resolution live imaging and transcriptomic analyses identified RPE mitochondria as an early driver of retinal dysfunction. Loss of mitochondrial fission protein 1 (MTFP1) in Grn -/- RPE causes mitochondrial hyperfusion and bioenergetic defects, leading to NF-kB-mediated activation of complement C3a-C3a receptor signaling, which drives further mitochondrial hyperfusion and retinal inflammation. C3aR antagonism restores RPE mitochondrial integrity and limits subretinal microglial activation. Our study identifies a previously unrecognized mechanism by which progranulin modulates mitochondrial integrity and complement-mediated neuroinflammation.
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Trincão-Marques J, Ayton LN, Hickey DG, Marques-Neves C, Guymer RH, Edwards TL, Sousa DC. Gene and cell therapy for age-related macular degeneration: A review. Surv Ophthalmol 2024:S0039-6257(24)00049-3. [PMID: 38735629 DOI: 10.1016/j.survophthal.2024.05.002] [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: 07/03/2023] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/14/2024]
Abstract
Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss among the elderly in Western communities, with an estimated global prevalence of 10 - 20% in people older than 65 years. AMD leads to central vision loss due to degeneration of the photoreceptors, retinal pigment epithelium and the choriocapillaris. Beckman's classification for AMD, based upon color fundus photographs, divides the disease into early, intermediate, and late forms. The late, vision-threatening stage includes both neovascular AMD and geographic atrophy. Despite its high prevalence and impact on patients' quality of life, treatment options for AMD are limited. While neovascular AMD can be medically managed with anti-VEGF intravitreal injections, until very recently there has been no approved treatment options for atrophic AMD; however, in February 2023 the first treatment for geographic atrophy - pegcetacoplan - was approved by the US FDA. We describe the current landscape of potential gene and cell therapeutic strategies for late-stage AMD, with an emphasis on the therapeutic options that might become available in the next few years.
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Affiliation(s)
- José Trincão-Marques
- Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Vision Sciences Study Centre, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Lauren N Ayton
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia
| | - Doron G Hickey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Carlos Marques-Neves
- Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Vision Sciences Study Centre, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia
| | - David Cordeiro Sousa
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Australia; Vision Sciences Study Centre, Faculdade de Medicina, Universidade de Lisboa, Portugal.
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5
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Landowski M, Gogoi P, Ikeda S, Ikeda A. Roles of transmembrane protein 135 in mitochondrial and peroxisomal functions - implications for age-related retinal disease. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1355379. [PMID: 38576540 PMCID: PMC10993500 DOI: 10.3389/fopht.2024.1355379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Aging is the most significant risk factor for age-related diseases in general, which is true for age-related diseases in the eye including age-related macular degeneration (AMD). Therefore, in order to identify potential therapeutic targets for these diseases, it is crucial to understand the normal aging process and how its mis-regulation could cause age-related diseases at the molecular level. Recently, abnormal lipid metabolism has emerged as one major aspect of age-related symptoms in the retina. Animal models provide excellent means to identify and study factors that regulate lipid metabolism in relation to age-related symptoms. Central to this review is the role of transmembrane protein 135 (TMEM135) in the retina. TMEM135 was identified through the characterization of a mutant mouse strain exhibiting accelerated retinal aging and positional cloning of the responsible mutation within the gene, indicating the crucial role of TMEM135 in regulating the normal aging process in the retina. Over the past decade, the molecular functions of TMEM135 have been explored in various models and tissues, providing insights into the regulation of metabolism, particularly lipid metabolism, through its action in multiple organelles. Studies indicated that TMEM135 is a significant regulator of peroxisomes, mitochondria, and their interaction. Here, we provide an overview of the molecular functions of TMEM135 which is crucial for regulating mitochondria, peroxisomes, and lipids. The review also discusses the age-dependent phenotypes in mice with TMEM135 perturbations, emphasizing the importance of a balanced TMEM135 function for the health of the retina and other tissues including the heart, liver, and adipose tissue. Finally, we explore the potential roles of TMEM135 in human age-related retinal diseases, connecting its functions to the pathobiology of AMD.
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Affiliation(s)
- Michael Landowski
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Purnima Gogoi
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
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Chu L, Bi C, Wang C, Zhou H. The Relationship between Complements and Age-Related Macular Degeneration and Its Pathogenesis. J Ophthalmol 2024; 2024:6416773. [PMID: 38205100 PMCID: PMC10776198 DOI: 10.1155/2024/6416773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/08/2023] [Accepted: 12/23/2023] [Indexed: 01/12/2024] Open
Abstract
Age-related macular degeneration is a retinal disease that causes permanent loss of central vision in people over the age of 65. Its pathogenesis may be related to mitochondrial dysfunction, inflammation, apoptosis, autophagy, complement, intestinal flora, and lipid disorders. In addition, the patient's genes, age, gender, cardiovascular disease, unhealthy diet, and living habits may also be risk factors for this disease. Complement proteins are widely distributed in serum and tissue fluid. In the early 21st century, a connection was found between the complement cascade and age-related macular degeneration. However, little is known about the effect of complement factors on the pathogenesis of age-related macular degeneration. This article reviews the factors associated with age-related macular degeneration, the relationship between each factor and complement, the related functions, and variants and provides new ideas for the treatment of this disease.
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Affiliation(s)
- Liyuan Chu
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
| | - Chaoran Bi
- College of Traditional Chinese Medicine, Hainan Medical University, Haikou, Hainan, China
| | - Caiming Wang
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
| | - Hongyan Zhou
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
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Aziz AA, Khan H, Khanani ZA, Thomas MJ, Khan H, Ahmed A, Gahn GM, Khanani AM. Review of Gene Therapy Clinical Trials for Retinal Diseases. Int Ophthalmol Clin 2024; 64:141-151. [PMID: 38146887 DOI: 10.1097/iio.0000000000000517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
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Tan LX, Germer CJ, Thamban T, La Cunza N, Lakkaraju A. Optineurin tunes outside-in signaling to regulate lysosome biogenesis and phagocytic clearance in the retina. Curr Biol 2023; 33:3805-3820.e7. [PMID: 37586372 PMCID: PMC10529777 DOI: 10.1016/j.cub.2023.07.031] [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: 03/23/2023] [Revised: 06/16/2023] [Accepted: 07/19/2023] [Indexed: 08/18/2023]
Abstract
Balancing the competing demands of phagolysosomal degradation and autophagy is a significant challenge for phagocytic tissues. Yet how this plasticity is accomplished in health and disease is poorly understood. In the retina, circadian phagocytosis and degradation of photoreceptor outer segments by the postmitotic retinal pigment epithelium (RPE) are essential for healthy vision. Disrupted autophagy due to mechanistic target of rapamycin (mTOR) overactivation in the RPE is associated with blinding macular degenerations; however, outer segment degradation is unaffected in these diseases, indicating that distinct mechanisms regulate these clearance mechanisms. Here, using advanced imaging and mouse models, we identify optineurin as a key regulator that tunes phagocytosis and lysosomal capacity to meet circadian demands and helps prioritize outer segment clearance by the RPE in macular degenerations. High-resolution live-cell imaging implicates optineurin in scissioning outer segment tips prior to engulfment, analogous to microglial trogocytosis of neuronal processes. Optineurin is essential for recruiting light chain 3 (LC3), which anchors outer segment phagosomes to microtubules and facilitates phagosome maturation and fusion with lysosomes. This dynamically activates transcription factor EB (TFEB) to induce lysosome biogenesis in an mTOR-independent, transient receptor potential-mucolipin 1 (TRPML1)-dependent manner. RNA-seq analyses show that expression of TFEB target genes temporally tracks with optineurin recruitment and that lysosomal and autophagy genes are controlled by distinct transcriptional programs in the RPE. The unconventional plasma membrane-to-nucleus signaling mediated by optineurin ensures outer segment degradation under conditions of impaired autophagy in macular degeneration models. Independent regulation of these critical clearance mechanisms would help safeguard the metabolic fitness of the RPE throughout the organismal lifespan.
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Affiliation(s)
- Li Xuan Tan
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Colin J Germer
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Thushara Thamban
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nilsa La Cunza
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Anatomy, School of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
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Tong Y, Wu Y, Ma J, Ikeda M, Ide T, Griffin CT, Ding XQ, Wang S. Comparative mechanistic study of RPE cell death induced by different oxidative stresses. Redox Biol 2023; 65:102840. [PMID: 37566944 PMCID: PMC10440584 DOI: 10.1016/j.redox.2023.102840] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023] Open
Abstract
Oxidative stress is hypothesized to drive the progression of age-related macular degeneration (AMD). Retinal pigment epithelial (RPE) cell layer is important for supporting the function of retina and is particularly susceptible to oxidative stress-induced cell death. How RPE cells die in AMD, especially in geographic atrophy (GA), a late stage of dry AMD, is still controversial. The goal of this study is to compare the features and mechanisms of RPE cell death induced by different oxidative stresses, to identify potential universal therapeutic targets for GA. RPE cell death was induced both in vitro and ex vivo by 4-Hydroxynonenal (4-HNE), a major product of lipid peroxidation, sodium iodate (NaIO3) that has been widely used to model RPE cell death in dry AMD, a ferroptosis inducer RAS-selective lethal 3 (RSL3) or a necroptosis inducer shikonin. We found that RPE necroptosis and ferroptosis show common and distinct features. Common features include receptor-interacting protein kinase (RIPK)1/RIPK3 activation and lipid reactive oxygen species (ROS) accumulation, although lipid ROS accumulation is much milder during necroptosis. This supports cross talk between RPE ferroptosis and necroptosis pathways and is consistent with the rescue of RPE necroptosis and ferroptosis by RIPK1 inhibitor Necrostatin-1 (Nec-1) or in Ripk3-/- RPE explants. Distinct feature includes activated mixed lineage kinase domain like pseudokinase (MLKL) that is translocated to the cell membrane during necroptosis, which is not happening in ferroptosis. This is consistent with the failure to rescue RPE ferroptosis by MLKL inhibitor necrosulfonamide (NSA) or in Mlkl-/- RPE explants. Using this framework, we found that 4-HNE and NaIO3 induced RPE cell death likely through necroptosis based on the molecular features and the rescuing effect by multiple inhibitors. Our studies suggest that multiple markers and inhibitors are required to distinguish RPE necroptosis and ferroptosis, and that necroptosis inhibitor Nec-1 could be a potential therapeutic compound for GA since it inhibits RIPK1/RIPK3 activation and lipid ROS accumulation occurred in both necroptosis and ferroptosis pathways.
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Affiliation(s)
- Yao Tong
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, 70118, USA
| | - Yinga Wu
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, 70118, USA
| | - Jing Ma
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, 70118, USA
| | - Masataka Ikeda
- Department of Cardiovascular Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomomi Ide
- Department of Cardiovascular Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Courtney T Griffin
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA; Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Shusheng Wang
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, 70118, USA; Department of Ophthalmology, Tulane University, New Orleans, LA, 70118, USA; Tulane Personalized Health Institute, Tulane University, New Orleans, LA, 70112, USA.
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Huang T, Wang Y, Wang Z, Long Q, Li Y, Chen D. Complement-mediated inflammation and mitochondrial energy metabolism in the proteomic profile of myopic human corneas. J Proteomics 2023; 285:104949. [PMID: 37331426 DOI: 10.1016/j.jprot.2023.104949] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/23/2023] [Accepted: 06/05/2023] [Indexed: 06/20/2023]
Abstract
Myopia is one of the most common causes of visual impairment worldwide. To identify proteins related to myopiagenesis, data-independent acquisition proteomic analysis was performed using corneal lenticules of myopic patients who underwent small incision lenticule extraction surgery. A total of 19 lenticules from 19 age and sex-matched patients were analyzed, 10 in high refractive error (HR, spherical equivalent over -6.00 D) group and 9 in low refractive error (LR, spherical equivalent between -3.00 and - 1.00 D) group. Differentially expressed proteins (DEPs) were identified by comparing the corneal proteome between the two groups. Functional analyses were performed to explore the biological pathways and interactions of the DEPs. 107 DEPs (67 upregulated and 40 downregulated in HR group, compared to LR) were identified from 2138 quantified proteins. Functional analyses indicated that upregulated proteins were primarily involved in the complement pathways and extracellular matrix (ECM) remodeling, while downregulated proteins were involved in mitochondrial energy metabolism. Western blot analysis confirmed increased complement C3a and apolipoprotein E in HR samples, further supporting the proteomics data. In conclusion, this proteomic study reveals that proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism might be key effectors in myopiagenesis. SIGNIFICANCE: Myopia has become one of the most prevalent causes of visual impairment, especially in Asia. The underlying mechanism of myopia development is still up for debate. This study compares the proteomic profiles of high and low myopic corneas, identifying differentially expressed proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism. The findings of this study could provide novel insights into the pathogenesis of myopia. The complement system and mitochondrial energy metabolism may provide potential therapeutic targets in the treatment and prevention of myopia.
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Affiliation(s)
- Tianze Huang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Yuchen Wang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Zhonghai Wang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Qin Long
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Ying Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Di Chen
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China.
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Abyadeh M, Gupta V, Paulo JA, Sheriff S, Shadfar S, Fitzhenry M, Amirkhani A, Gupta V, Salekdeh GH, Haynes PA, Graham SL, Mirzaei M. Apolipoprotein ε in Brain and Retinal Neurodegenerative Diseases. Aging Dis 2023; 14:1311-1330. [PMID: 37199411 PMCID: PMC10389820 DOI: 10.14336/ad.2023.0312-1] [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: 01/11/2023] [Accepted: 03/12/2023] [Indexed: 05/19/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia that remains incurable and has become a major medical, social, and economic challenge worldwide. AD is characterized by pathological hallmarks of senile plaques (SP) and neurofibrillary tangles (NFTs) that damage the brain up to twenty years before a clinical diagnosis is made. Interestingly these pathological features have also been observed in retinal neurodegenerative diseases including age related macular degeneration (ARMD), glaucoma and diabetic retinopathy (DR). An association of AD with these diseases has been suggested in epidemiological studies and several common pathological events and risk factors have been identified between these diseases. The E4 allele of Apolipoprotein E (APOE) is a well-established genetic risk factor for late onset AD. The ApoE ε4 allele is also associated with retinal neurodegenerative diseases however in contrast to AD, it is considered protective in AMD, likewise ApoE E2 allele, which is a protective factor for AD, has been implicated as a risk factor for AMD and glaucoma. This review summarizes the evidence on the effects of ApoE in retinal neurodegenerative diseases and discusses the overlapping molecular pathways in AD. The involvement of ApoE in regulating amyloid beta (Aβ) and tau pathology, inflammation, vascular integrity, glucose metabolism and vascular endothelial growth factor (VEGF) signaling is also discussed.
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Affiliation(s)
| | - Vivek Gupta
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Macquarie Park, North Ryde, Sydney, NSW 2109, Australia.
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Samran Sheriff
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Macquarie Park, North Ryde, Sydney, NSW 2109, Australia.
| | - Sina Shadfar
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Macquarie Park, North Ryde, Sydney, NSW 2109, Australia.
| | - Matthew Fitzhenry
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW 2113, Australia.
| | - Ardeshir Amirkhani
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW 2113, Australia.
| | - Veer Gupta
- School of Medicine, Deakin University, VIC, Australia.
| | - Ghasem H Salekdeh
- School of Natural Sciences, Macquarie University, Macquarie Park, NSW 2109, Australia.
| | - Paul A Haynes
- School of Natural Sciences, Macquarie University, Macquarie Park, NSW 2109, Australia.
| | - Stuart L Graham
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Macquarie Park, North Ryde, Sydney, NSW 2109, Australia.
| | - Mehdi Mirzaei
- Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Macquarie Park, North Ryde, Sydney, NSW 2109, Australia.
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12
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Busch C, Rau S, Sekulic A, Perie L, Huber C, Gehrke M, Joussen AM, Zipfel PF, Wildner G, Skerka C, Strauß O. Increased plasma level of terminal complement complex in AMD patients: potential functional consequences for RPE cells. Front Immunol 2023; 14:1200725. [PMID: 37359546 PMCID: PMC10287163 DOI: 10.3389/fimmu.2023.1200725] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Purpose Polymorphisms in complement genes are risk-associated for age-related macular degeneration (AMD). Functional analysis revealed a common deficiency to control the alternative complement pathway by risk-associated gene polymorphisms. Thus, we investigated the levels of terminal complement complex (TCC) in the plasma of wet AMD patients with defined genotypes and the impact of the complement activation of their plasma on second-messenger signaling, gene expression, and cytokine/chemokine secretion in retinal pigment epithelium (RPE) cells. Design Collection of plasma from patients with wet AMD (n = 87: 62% female and 38% male; median age 77 years) and controls (n = 86: 39% female and 61% male; median age 58 years), grouped for risk factor smoking and genetic risk alleles CFH 402HH and ARMS2 rs3750846, determination of TCC levels in the plasma, in vitro analysis on RPE function during exposure to patients' or control plasma as a complement source. Methods Genotyping, measurement of TCC concentrations, ARPE-19 cell culture, Ca2+ imaging, gene expression by qPCR, secretion by multiplex bead analysis of cell culture supernatants. Main outcome measures TCC concentration in plasma, intracellular free Ca2+, relative mRNA levels, cytokine secretion. Results TCC levels in the plasma of AMD patients were five times higher than in non-AMD controls but did not differ in plasma from carriers of the two risk alleles. Complement-evoked Ca2+ elevations in RPE cells differed between patients and controls with a significant correlation between TCC levels and peak amplitudes. Comparing the Ca2+ signals, only between the plasma of smokers and non-smokers, as well as heterozygous (CFH 402YH) and CFH 402HH patients, revealed differences in the late phase. Pre-stimulation with complement patients' plasma led to sensitization for complement reactions by RPE cells. Gene expression for surface molecules protective against TCC and pro-inflammatory cytokines increased after exposure to patients' plasma. Patients' plasma stimulated the secretion of pro-inflammatory cytokines in the RPE. Conclusion TCC levels were higher in AMD patients but did not depend on genetic risk factors. The Ca2+ responses to patients' plasma as second-messenger represent a shift of RPE cells to a pro-inflammatory phenotype and protection against TCC. We conclude a substantial role of high TCC plasma levels in AMD pathology.
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Affiliation(s)
- Catharina Busch
- Department of Ophthalmology, University Hospital Leipzig, Leipzig, Germany
| | - Saskia Rau
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin Institute of Health, Humboldt-University, Berlin, Germany
| | - Andjela Sekulic
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin Institute of Health, Humboldt-University, Berlin, Germany
| | - Luce Perie
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Christian Huber
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin Institute of Health, Humboldt-University, Berlin, Germany
| | - Miranda Gehrke
- Section of Immunobiology, Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
| | - Antonia M. Joussen
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin Institute of Health, Humboldt-University, Berlin, Germany
| | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
- Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany
| | - Gerhild Wildner
- Section of Immunobiology, Department of Ophthalmology, University Hospital, Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität, Berlin Institute of Health, Humboldt-University, Berlin, Germany
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13
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Hammadi S, Tzoumas N, Ferrara M, Meschede IP, Lo K, Harris C, Lako M, Steel DH. Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration. J Clin Med 2023; 12:2870. [PMID: 37109207 PMCID: PMC10145879 DOI: 10.3390/jcm12082870] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.
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Affiliation(s)
- Sarah Hammadi
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Nikolaos Tzoumas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
| | | | - Ingrid Porpino Meschede
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Katharina Lo
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Claire Harris
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David H. Steel
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
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14
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Malek G, Campisi J, Kitazawa K, Webster C, Lakkaraju A, Skowronska-Krawczyk D. Does senescence play a role in age-related macular degeneration? Exp Eye Res 2022; 225:109254. [PMID: 36150544 PMCID: PMC10032649 DOI: 10.1016/j.exer.2022.109254] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 12/29/2022]
Abstract
Advanced age is the most established risk factor for developing age-related macular degeneration (AMD), one of the leading causes of visual impairment in the elderly, in Western and developed countries. Similarly, after middle age, there is an exponential increase in pathologic molecular and cellular events that can induce senescence, traditionally defined as an irreversible loss of the cells' ability to divide and most recently reported to also occur in select post-mitotic and terminally differentiated cells, such as neurons. Together these facts raise the question as to whether or not cellular senescence, may play a role in the development of AMD. A number of studies have reported the effect of ocular-relevant inducers of senescence using primarily in vitro models of poorly polarized, actively dividing retinal pigment epithelial (RPE) cell lines. However, in interpretating the data, the fidelity of these culture models to the RPE in vivo, must be considered. Fewer studies have explored the presence and/or impact of senescent cells in in vivo models that present with phenotypic features of AMD, leaving this an open field for further investigation. The goal of this review is to discuss current thoughts on the potential role of senescence in AMD development and progression, with consideration of the model systems used and their relevance to human disease.
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Affiliation(s)
- Goldis Malek
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
| | - Judith Campisi
- Buck Institute for Research on Aging, Novato, CA, USA; Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Koji Kitazawa
- Buck Institute for Research on Aging, Novato, CA, USA; Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Corey Webster
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Aparna Lakkaraju
- Departments of Ophthalmology and Anatomy, School of Medicine, University of California, San Francisco, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California, Irvine, CA, USA
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15
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Tan LX, Li J, Germer CJ, Lakkaraju A. Analysis of mitochondrial dynamics and function in the retinal pigment epithelium by high-speed high-resolution live imaging. Front Cell Dev Biol 2022; 10:1044672. [PMID: 36393836 PMCID: PMC9651161 DOI: 10.3389/fcell.2022.1044672] [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: 09/14/2022] [Accepted: 10/19/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial dysfunction is strongly implicated in neurodegenerative diseases including age-related macular degeneration (AMD), which causes irreversible blindness in over 50 million older adults worldwide. A key site of insult in AMD is the retinal pigment epithelium (RPE), a monolayer of postmitotic polarized cells that performs essential functions for photoreceptor health and vision. Recent studies from our group and others have identified several features of mitochondrial dysfunction in AMD including mitochondrial fragmentation and bioenergetic defects. While these studies provide valuable insight at fixed points in time, high-resolution, high-speed live imaging is essential for following mitochondrial injury in real time and identifying disease mechanisms. Here, we demonstrate the advantages of live imaging to investigate RPE mitochondrial dynamics in cell-based and mouse models. We show that mitochondria in the RPE form extensive networks that are destroyed by fixation and discuss important live imaging considerations that can interfere with accurate evaluation of mitochondrial integrity such as RPE differentiation status and acquisition parameters. Our data demonstrate that RPE mitochondria show localized heterogeneities in membrane potential and ATP production that could reflect focal changes in metabolism and oxidative stress. Contacts between the mitochondria and organelles such as the ER and lysosomes mediate calcium flux and mitochondrial fission. Live imaging of mouse RPE flatmounts revealed a striking loss of mitochondrial integrity in albino mouse RPE compared to pigmented mice that could have significant functional consequences for cellular metabolism. Our studies lay a framework to guide experimental design and selection of model systems for evaluating mitochondrial health and function in the RPE.
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Affiliation(s)
- Li Xuan Tan
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
| | - Jianlong Li
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, CA, United States
| | - Colin J. Germer
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, United States
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, United States
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, United States
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA, United States
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16
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Bharti K, den Hollander AI, Lakkaraju A, Sinha D, Williams DS, Finnemann SC, Bowes-Rickman C, Malek G, D'Amore PA. Cell culture models to study retinal pigment epithelium-related pathogenesis in age-related macular degeneration. Exp Eye Res 2022; 222:109170. [PMID: 35835183 PMCID: PMC9444976 DOI: 10.1016/j.exer.2022.109170] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/23/2022] [Accepted: 06/29/2022] [Indexed: 11/04/2022]
Abstract
Age-related macular degeneration (AMD) is a disease that affects the macula - the central part of the retina. It is a leading cause of irreversible vision loss in the elderly. AMD onset is marked by the presence of lipid- and protein-rich extracellular deposits beneath the retinal pigment epithelium (RPE), a monolayer of polarized, pigmented epithelial cells located between the photoreceptors and the choroidal blood supply. Progression of AMD to the late nonexudative "dry" stage of AMD, also called geographic atrophy, is linked to progressive loss of areas of the RPE, photoreceptors, and underlying choriocapillaris leading to a severe decline in patients' vision. Differential susceptibility of macular RPE in AMD and the lack of an anatomical macula in most lab animal models has promoted the use of in vitro models of the RPE. In addition, the need for high throughput platforms to test potential therapies has driven the creation and characterization of in vitro model systems that recapitulate morphologic and functional abnormalities associated with human AMD. These models range from spontaneously formed cell line ARPE19, immortalized cell lines such as hTERT-RPE1, RPE-J, and D407, to primary human (fetal or adult) or animal (mouse and pig) RPE cells, and embryonic and induced pluripotent stem cell (iPSC) derived RPE. Hallmark RPE phenotypes, such as cobblestone morphology, pigmentation, and polarization, vary significantly betweendifferent models and culture conditions used in different labs, which would directly impact their usability for investigating different aspects of AMD biology. Here the AMD Disease Models task group of the Ryan Initiative for Macular Research (RIMR) provides a summary of several currently used in vitro RPE models, historical aspects of their development, RPE phenotypes that are attainable in these models, their ability to model different aspects of AMD pathophysiology, and pros/cons for their use in the RPE and AMD fields. In addition, due to the burgeoning use of iPSC derived RPE cells, the critical need for developing standards for differentiating and rigorously characterizing RPE cell appearance, morphology, and function are discussed.
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Affiliation(s)
- Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, NIH, Bethesda, MD, USA.
| | - Anneke I den Hollander
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands; AbbVie, Genomics Research Center, Cambridge, MA, USA.
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, USA.
| | - Debasish Sinha
- Department of Ophthalmology, Cell Biology and Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - David S Williams
- Stein Eye Institute, Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
| | - Silvia C Finnemann
- Center of Cancer, Genetic Diseases, and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY, USA.
| | - Catherine Bowes-Rickman
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA.
| | - Goldis Malek
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
| | - Patricia A D'Amore
- Mass Eye and Ear, Departments of Ophthalmology and Pathology, Harvard Medical School, Boston, MA, USA.
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17
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Khanani AM, Thomas MJ, Aziz AA, Weng CY, Danzig CJ, Yiu G, Kiss S, Waheed NK, Kaiser PK. Review of gene therapies for age-related macular degeneration. Eye (Lond) 2022; 36:303-311. [PMID: 35017696 PMCID: PMC8807824 DOI: 10.1038/s41433-021-01842-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/25/2021] [Accepted: 11/03/2021] [Indexed: 02/03/2023] Open
Abstract
Gene therapies aim to deliver a therapeutic payload to specified tissues with underlying protein deficiency. Since the 1990s, gene therapies have been explored as potential treatments for chronic conditions requiring lifetime care and medical management. Ocular gene therapies target a range of ocular disorders, but retinal diseases are of particular importance due to the prevalence of retinal disease and the current treatment burden of such diseases on affected patients, as well as the challenge of properly delivering these therapies to the target tissue. The purpose of this review is to provide an update on the most current data available for five different retinal gene therapies currently undergoing clinical trials for use against age-related macular degeneration (AMD) and the development of novel delivery routes for the administration of such therapies. Research has been performed and compiled from PubMed and the select authors of this manuscript on the treatment and effectiveness of five current retinal gene therapies: Luxturna, ADVM-022, RGX-314, GT-005, and HMR59. We present the available data of current clinical trials for the treatment of neovascular and dry age-related macular degeneration with different AAV-based gene therapies. We also present current research on the progress of developing novel routes of administration for ocular gene therapies. Retinal gene therapies offer the potential for life-changing treatment for chronic conditions like age-related macular degeneration with a single administration. In doing so, gene therapies change the landscape of treatment options for these chronic conditions for both patient and provider.
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Affiliation(s)
- Arshad M. Khanani
- grid.492896.8Sierra Eye Associates, Reno, NV USA ,grid.266818.30000 0004 1936 914XThe University of Nevada, Reno School of Medicine, Reno, NV USA
| | - Mathew J. Thomas
- grid.266818.30000 0004 1936 914XThe University of Nevada, Reno School of Medicine, Reno, NV USA
| | - Aamir A. Aziz
- grid.492896.8Sierra Eye Associates, Reno, NV USA ,grid.266818.30000 0004 1936 914XThe University of Nevada, Reno School of Medicine, Reno, NV USA
| | - Christina Y. Weng
- grid.39382.330000 0001 2160 926XDepartment of Ophthalmology, Baylor College of Medicine, Houston, TX USA
| | - Carl J. Danzig
- Rand Eye Institute, Deerfield Beach, FL USA ,grid.255951.fFlorida Atlantic University, Charles E. Schmidt College of Medicine, Boca Raton, FL USA
| | - Glenn Yiu
- grid.27860.3b0000 0004 1936 9684Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA USA
| | - Szilárd Kiss
- grid.413734.60000 0000 8499 1112Department of Ophthalmology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY USA
| | - Nadia K. Waheed
- grid.67033.310000 0000 8934 4045Department of Ophthalmology, Tufts University School of Medicine, Boston, MA USA
| | - Peter K. Kaiser
- grid.239578.20000 0001 0675 4725Cole Eye Institute, Cleveland Clinic, Cleveland, OH USA
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18
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Lewandowski D, Foik AT, Smidak R, Choi EH, Zhang J, Hoang T, Tworak A, Suh S, Leinonen H, Dong Z, Pinto AF, Tom E, Luu JC, Lee JY, Ma X, Bieberich E, Blackshaw S, Saghatelian A, Lyon DC, Skowronska-Krawczyk D, Tabaka M, Palczewski K. Inhibition of ceramide accumulation in AdipoR1-/- mice increases photoreceptor survival and improves vision. JCI Insight 2022; 7:156301. [PMID: 35015730 PMCID: PMC8876453 DOI: 10.1172/jci.insight.156301] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/05/2022] [Indexed: 11/20/2022] Open
Abstract
Adiponectin receptor 1 (ADIPOR1) is a lipid and glucose metabolism regulator that possesses intrinsic ceramidase activity. Mutations of the ADIPOR1 gene have been associated with nonsyndromic and syndromic retinitis pigmentosa. Here, we show that the absence of AdipoR1 in mice leads to progressive photoreceptor degeneration, significant reduction of electroretinogram amplitudes, decreased retinoid content in the retina, and reduced cone opsin expression. Single-cell RNA-Seq results indicate that ADIPOR1 encoded the most abundantly expressed ceramidase in mice and one of the 2 most highly expressed ceramidases in the human retina, next to acid ceramidase ASAH1. We discovered an accumulation of ceramides in the AdipoR1–/– retina, likely due to insufficient ceramidase activity for healthy retina function, resulting in photoreceptor death. Combined treatment with desipramine/L-cycloserine (DC) lowered ceramide levels and exerted a protective effect on photoreceptors in AdipoR1–/– mice. Moreover, we observed improvement in cone-mediated retinal function in the DC-treated animals. Lastly, we found that prolonged DC treatment corrected the electrical responses of the primary visual cortex to visual stimuli, approaching near-normal levels for some parameters. These results highlight the importance of ADIPOR1 ceramidase in the retina and show that pharmacological inhibition of ceramide generation can provide a therapeutic strategy for ADIPOR1-related retinopathy.
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Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Andrzej T Foik
- International Center for Translational Eye Research, Institute of Physical Chemistry PAS, Warsaw, Poland
| | - Roman Smidak
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Elliot H Choi
- Department of Pharmacology, Case Western Reserve University, Cleveland, United States of America
| | - Jianye Zhang
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Thanh Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States of America
| | - Aleksander Tworak
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Susie Suh
- Department of Pharmacology, Case Western Reserve University, Cleveland, United States of America
| | - Henri Leinonen
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Zhiqian Dong
- Department of Medical Devices, Polgenix Inc., Cleveland, United States of America
| | - Antonio Fm Pinto
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, United States of America
| | - Emily Tom
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Jennings C Luu
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Joan Y Lee
- MetroHealth Medical Center, Case Western Reserve University, Cleveland, United States of America
| | - Xiuli Ma
- Department of Medical Devices, Polgenix Inc, Cleveland, United States of America
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky, Lexington, United States of America
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, John Hopkins School of Medicine, Baltimore, United States of America
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, United States of America
| | - David C Lyon
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States of America
| | | | - Marcin Tabaka
- International Center for Translational Eye Research, Institute of Physical Chemistry PAS, Warsaw, Poland
| | - Krzysztof Palczewski
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
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19
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La Cunza N, Tan LX, Thamban T, Germer CJ, Rathnasamy G, Toops KA, Lakkaraju A. Mitochondria-dependent phase separation of disease-relevant proteins drives pathological features of age-related macular degeneration. JCI Insight 2021; 6:142254. [PMID: 33822768 PMCID: PMC8262309 DOI: 10.1172/jci.insight.142254] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 03/31/2021] [Indexed: 01/21/2023] Open
Abstract
Age-related macular degeneration (AMD) damages the retinal pigment epithelium (RPE), the tissue that safeguards photoreceptor health, leading to irreversible vision loss. Polymorphisms in cholesterol and complement genes are implicated in AMD, yet mechanisms linking risk variants to RPE injury remain unclear. We sought to determine how allelic variants in the apolipoprotein E cholesterol transporter modulate RPE homeostasis and function. Using live-cell imaging, we show that inefficient cholesterol transport by the AMD risk-associated ApoE2 increases RPE ceramide, leading to autophagic defects and complement-mediated mitochondrial damage. Mitochondrial injury drives redox state–sensitive cysteine-mediated phase separation of ApoE2, forming biomolecular condensates that could nucleate drusen. The protective ApoE4 isoform lacks these cysteines and is resistant to phase separation and condensate formation. In Abca–/– Stargardt macular degeneration mice, mitochondrial dysfunction induces liquid-liquid phase separation of p62/SQSTM1, a multifunctional protein that regulates autophagy. Drugs that decrease RPE cholesterol or ceramide prevent mitochondrial injury and phase separation in vitro and in vivo. In AMD donor RPE, mitochondrial fragmentation correlates with ApoE and p62 condensates. Our studies demonstrate that major AMD genetic and biological risk pathways converge upon RPE mitochondria, and identify mitochondrial stress-mediated protein phase separation as an important pathogenic mechanism and promising therapeutic target in AMD.
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Affiliation(s)
- Nilsa La Cunza
- Department of Ophthalmology, School of Medicine, and.,Pharmaceutical Sciences and Pharmacogenomics Graduate Program, Graduate Division, University of California, San Francisco, California, USA
| | - Li Xuan Tan
- Department of Ophthalmology, School of Medicine, and
| | | | - Colin J Germer
- Department of Ophthalmology, School of Medicine, and.,Pharmaceutical Sciences and Pharmacogenomics Graduate Program, Graduate Division, University of California, San Francisco, California, USA
| | | | - Kimberly A Toops
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, and.,Pharmaceutical Sciences and Pharmacogenomics Graduate Program, Graduate Division, University of California, San Francisco, California, USA.,Department of Anatomy, School of Medicine, University of California, San Francisco, California, USA
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20
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Toll-like Receptor 2 Facilitates Oxidative Damage-Induced Retinal Degeneration. Cell Rep 2021; 30:2209-2224.e5. [PMID: 32075760 PMCID: PMC7179253 DOI: 10.1016/j.celrep.2020.01.064] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/18/2019] [Accepted: 01/21/2020] [Indexed: 12/11/2022] Open
Abstract
Retinal degeneration is a form of neurodegenerative disease and is the leading cause of vision loss globally. The Toll-like receptors (TLRs) are primary components of the innate immune system involved in signal transduction. Here we show that TLR2 induces complement factors C3 and CFB, the common and rate-limiting factors of the alternative pathway in both retinal pigment epithelial (RPE) cells and mononuclear phagocytes. Neutralization of TLR2 reduces opsonizing fragments of C3 in the outer retina and protects photoreceptor neurons from oxidative stress-induced degeneration. TLR2 deficiency also preserves tight junction expression and promotes RPE resistance to fragmentation. Finally, oxidative stress-induced formation of the terminal complement membrane attack complex and Iba1+ cell infiltration are strikingly inhibited in the TLR2-deficient retina. Our data directly implicate TLR2 as a mediator of retinal degeneration in response to oxidative stress and present TLR2 as a bridge between oxidative damage and complement-mediated retinal pathology. Oxidative stress and complement deposition are common to many retinal degenerative diseases. Mulfaul et al. demonstrate that TLR2 blockade protects against photoreceptor neuronal cell death and RPE fragmentation in experimental models of oxidative stress-induced retinal degeneration and present TLR2 as a bridge between oxidative damage and complement-mediated retinal pathology.
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21
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Abstract
Cholesterol is a quantitatively and biologically significant constituent of all mammalian cell membrane, including those that comprise the retina. Retinal cholesterol homeostasis entails the interplay between de novo synthesis, uptake, intraretinal sterol transport, metabolism, and efflux. Defects in these complex processes are associated with several congenital and age-related disorders of the visual system. Herein, we provide an overview of the following topics: (a) cholesterol synthesis in the neural retina; (b) lipoprotein uptake and intraretinal sterol transport in the neural retina and the retinal pigment epithelium (RPE); (c) cholesterol efflux from the neural retina and the RPE; and (d) biology and pathobiology of defects in sterol synthesis and sterol oxidation in the neural retina and the RPE. We focus, in particular, on studies involving animal models of monogenic disorders pertinent to the above topics, as well as in vitro models using biochemical, metabolic, and omic approaches. We also identify current knowledge gaps and opportunities in the field that beg further research in this topic area.
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Steven J Fliesler
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY, USA.
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22
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Simon MV, Basu SK, Qaladize B, Grambergs R, Rotstein NP, Mandal N. Sphingolipids as critical players in retinal physiology and pathology. J Lipid Res 2021; 62:100037. [PMID: 32948663 PMCID: PMC7933806 DOI: 10.1194/jlr.tr120000972] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established to participate in numerous processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is therefore crucial in the onset and progression of retinal diseases. This review examines the involvement of sphingolipids in retinal physiology and diseases. Ceramide (Cer) has emerged as a common mediator of inflammation and death of neuronal and retinal pigment epithelium cells in animal models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. Sphingosine-1-phosphate (S1P) has opposite roles, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1-phosphate may also contribute to uveitis. Notably, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), preserves neuronal viability and retinal function. These findings underscore the relevance of alterations in the sphingolipid metabolic network in the etiology of multiple retinopathies and highlight the potential of modulating their metabolism for the design of novel therapeutic approaches.
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Affiliation(s)
- M Victoria Simon
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Sandip K Basu
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bano Qaladize
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Richard Grambergs
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina.
| | - Nawajes Mandal
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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23
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Wang J, Wang Y, Yu D, Liu Q, Lin S, Tian R, Li J, Luo Y. Protective Effect of a Bispecific Fc-Fusion Protein on the Barrier of Human Retinal Pigment Epithelial Cells. Ophthalmic Res 2021; 64:656-663. [PMID: 33550303 DOI: 10.1159/000515053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/28/2021] [Indexed: 02/05/2023]
Abstract
INTRODUCTION The aim of the study was to evaluate the protective effects of IBI302, a bispecific Fc-fusion protein that theoretically can bind vascular endothelial growth factor (VEGF), complement C3b, and C4b in the barrier of the cultured human retinal pigment epithelial (hRPE) cells. METHODS Primary hRPE cells were isolated and cultured to monolayer barrier. hRPE monolayers were divided into the PBS control group, VEGF-Trap group, complement receptor 1 (CR1) group, and IBI302 group. Identification of hRPE cells, barrier function, inflammation factors, and immune response products was tested by immunofluorescent staining, transepithelial resistance (TER), and ELISA. RESULTS IBI302 treatment significantly improved the TER of the barrier of hRPE cells after complement-activated oxidative stress compared with the PBS control group, VEGF-Trap group, and CR1 group. The maximum effect of IBI302 on protecting hRPE cell viability was observed at the concentration of 1 μg/mL. The elevated expression of VEGF, chemokine (C-C Motif) ligand 2, C3a, C5a, and membrane attack complex was reduced by IBI302. CONCLUSION IBI302 could protect the barrier function of hRPE cells. IBI302 might be a potentially effective drug for the RPE barrier-associated ocular diseases.
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Affiliation(s)
- Jing Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yishen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Dechao Yu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Qiuhui Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shaofen Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Rong Tian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jia Li
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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24
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Nagai N, Kawashima H, Toda E, Homma K, Osada H, Guzman NA, Shibata S, Uchiyama Y, Okano H, Tsubota K, Ozawa Y. Renin-angiotensin system impairs macrophage lipid metabolism to promote age-related macular degeneration in mouse models. Commun Biol 2020; 3:767. [PMID: 33299105 PMCID: PMC7725839 DOI: 10.1038/s42003-020-01483-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 11/16/2020] [Indexed: 12/16/2022] Open
Abstract
Metabolic syndrome, a condition involving obesity and hypertension, increases the risk of aging-associated diseases such as age-related macular degeneration (AMD). Here, we demonstrated that high-fat diet (HFD)-fed mice accumulated oxidized low-density lipoprotein (ox-LDL) in macrophages through the renin–angiotensin system (RAS). The ox-LDL-loaded macrophages were responsible for visual impairment in HFD mice along with a disorder of the retinal pigment epithelium (RPE), which is required for photoreceptor outer segment renewal. RAS repressed ELAVL1, which reduced PPARγ, impeding ABCA1 induction to levels that are sufficient to excrete overloaded cholesterol within the macrophages. The ox-LDL-loaded macrophages expressed inflammatory cytokines and attacked the RPE. An antihypertensive drug, angiotensin II type 1 receptor (AT1R) blocker, resolved the decompensation of lipid metabolism in the macrophages and reversed the RPE condition and visual function in HFD mice. AT1R signaling could be a future therapeutic target for macrophage-associated aging diseases, such as AMD. Nagai et al. show that mice fed high-fat diet (HFD) accumulate oxidized low-density lipoprotein in macrophages through the renin–angiotensin system, which impairs visual function. They find that angiotensin II type 1 receptor (AT1R) improves the visual function of HFD mice, suggesting AT1R signaling as a potential therapeutic target for age-related macular degeneration.
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Affiliation(s)
- Norihiro Nagai
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan.,Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Hirohiko Kawashima
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan.,Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Eriko Toda
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Kohei Homma
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Hideto Osada
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Naymel A Guzman
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan.,Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Shinsuke Shibata
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo, 113-0033, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan
| | - Yoko Ozawa
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan. .,Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjukuku, Tokyo, 160-8582, Japan. .,Department of Ophthalmology, St. Luke's International Hospital, 9-1 Akashi-Cho, Chuo-Ku, Tokyo, 104-8560, Japan. .,St. Luke's International University, 9-1 Akashi-Cho, Tokyo, 104-8560, Japan.
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25
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Tzoumas N, Hallam D, Harris CL, Lako M, Kavanagh D, Steel DHW. Revisiting the role of factor H in age-related macular degeneration: Insights from complement-mediated renal disease and rare genetic variants. Surv Ophthalmol 2020; 66:378-401. [PMID: 33157112 DOI: 10.1016/j.survophthal.2020.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
Ophthalmologists are long familiar with the eye showing signs of systemic disease, but the association between age-related macular degeneration and abnormal complement activation, common to several renal disorders, has only recently been elucidated. Although complement activation products were identified in drusen almost three decades ago, it was not until the early 21st century that a single-nucleotide polymorphism in the complement factor H gene was identified as a major heritable determinant of age-related macular degeneration, galvanizing global efforts to unravel the pathogenesis of this common disease. Advances in proteomic analyses and familial aggregation studies have revealed distinctive clinical phenotypes segregated by the functional effects of common and rare genetic variants on the mature protein and its splice variant, factor H-like protein 1. The predominance of loss-of-function, N-terminal mutations implicate age-related macular degeneration as a disease of general complement dysregulation, offering several therapeutic avenues for its modulation. Here, we explore the molecular impact of these mutations/polymorphisms on the ability of variant factor H/factor H-like protein 1 to localize to polyanions, pentraxins, proinflammatory triggers, and cell surfaces across ocular and renal tissues and exert its multimodal regulatory functions and their clinical implications. Finally, we critically evaluate key therapeutic and diagnostic efforts in this rapidly evolving field.
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Affiliation(s)
- Nikolaos Tzoumas
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Dean Hallam
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Claire L Harris
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Kavanagh
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - David H W Steel
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; Sunderland Eye Infirmary, Sunderland, United Kingdom
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26
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Kaarniranta K, Uusitalo H, Blasiak J, Felszeghy S, Kannan R, Kauppinen A, Salminen A, Sinha D, Ferrington D. Mechanisms of mitochondrial dysfunction and their impact on age-related macular degeneration. Prog Retin Eye Res 2020; 79:100858. [PMID: 32298788 PMCID: PMC7650008 DOI: 10.1016/j.preteyeres.2020.100858] [Citation(s) in RCA: 246] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 12/21/2022]
Abstract
Oxidative stress-induced damage to the retinal pigment epithelium (RPE) is considered to be a key factor in age-related macular degeneration (AMD) pathology. RPE cells are constantly exposed to oxidative stress that may lead to the accumulation of damaged cellular proteins, lipids, nucleic acids, and cellular organelles, including mitochondria. The ubiquitin-proteasome and the lysosomal/autophagy pathways are the two major proteolytic systems to remove damaged proteins and organelles. There is increasing evidence that proteostasis is disturbed in RPE as evidenced by lysosomal lipofuscin and extracellular drusen accumulation in AMD. Nuclear factor-erythroid 2-related factor-2 (NFE2L2) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) are master transcription factors in the regulation of antioxidant enzymes, clearance systems, and biogenesis of mitochondria. The precise cause of RPE degeneration and the onset and progression of AMD are not fully understood. However, mitochondria dysfunction, increased reactive oxygen species (ROS) production, and mitochondrial DNA (mtDNA) damage are observed together with increased protein aggregation and inflammation in AMD. In contrast, functional mitochondria prevent RPE cells damage and suppress inflammation. Here, we will discuss the role of mitochondria in RPE degeneration and AMD pathology focused on mtDNA damage and repair, autophagy/mitophagy signaling, and regulation of inflammation. Mitochondria are putative therapeutic targets to prevent or treat AMD.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland and Kuopio University Hospital, P.O. Box 1627, FI-70211, Kuopio, Finland.
| | - Hannu Uusitalo
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland and Tays Eye Centre, Tampere University Hospital, P.O.Box 2000, 33521 Tampere, Finland
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236, Lodz, Poland
| | - Szabolcs Felszeghy
- Department of Biomedicine, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Ram Kannan
- The Stephen J. Ryan Initiative for Macular Research (RIMR), Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA, 90033, USA
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Debasish Sinha
- Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, PA 15224, USA; Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Room M035 Robert and Clarice Smith Bldg, 400 N Broadway, Baltimore, MD, 21287, USA
| | - Deborah Ferrington
- Department of Ophthalmology and Visual Neurosciences, 2001 6th St SE, University of Minnesota, Minneapolis, MN 55455, USA
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27
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Du Y, You L, Ni B, Sai N, Wang W, Sun M, Xu R, Yao Y, Zhang Z, Qu C, Yin X, Ni J. Phillyrin Mitigates Apoptosis and Oxidative Stress in Hydrogen Peroxide-Treated RPE Cells through Activation of the Nrf2 Signaling Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:2684672. [PMID: 33101585 PMCID: PMC7576358 DOI: 10.1155/2020/2684672] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 01/08/2023]
Abstract
Oxidative stress-induced dysfunction or apoptosis in retinal pigment epithelial (RPE) cells is an important cause of dry age-related macular degeneration (AMD). Although phillyrin has been shown to exert significant antioxidant effects, the underlying mechanism of action remains unclear. The purpose of this study was to investigate the protective effect of phillyrin on hydrogen peroxide- (H2O2-) induced oxidative stress damage in RPE cells and the potential mechanism involved. It was found that phillyrin significantly protected RPE cells from H2O2 cytotoxicity. Furthermore, phillyrin alleviated oxidative stress-induced apoptosis via inhibition of endogenous and exogenous apoptotic pathways. Compared with the H2O2-treated group, the expressions of cleaved caspase-3, cleaved caspase-9, cleaved polymerase (PARP), death receptor Fas, and cleaved caspase-8, as well as Bax/Bcl-2 ratio were decreased in RPE cells after the phillyrin intervention. In addition, phillyrin reversed the oxidative stress-induced reductions in superoxide dismutase (SOD) and glutathione (GSH) levels and annulled the elevations in reactive oxygen species (ROS) and malondialdehyde (MDA), thereby restoring oxidant-antioxidant homeostasis. Phillyrin treatment upregulated the expressions of cyclin E, cyclin-dependent kinase 2 (CDK2), and cyclin A and downregulated the expressions of p21 and p-p53, thereby reversing the G0/G1 cell cycle arrest in H2O2-treated RPE cells. Pretreatment with phillyrin also increased the expressions of nuclear factor-erythroid 2-related factor 2 (Nrf2), total Nrf2, heme oxygenase-1 (HO-1), and NAD(P)H: quinone oxidoreductases-1 (NQO-1) in RPE cells and inhibited the formation of Kelch-like ECH-associated protein 1 (Keap1)/Nrf2 protein complex. Thus, phillyrin effectively protected RPE cells from oxidative stress through activation of the Nrf2 signaling pathway and inhibition of the mitochondria-dependent apoptosis pathway.
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Affiliation(s)
- Yuanyuan Du
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Longtai You
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Boran Ni
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing 100029, China
| | - Na Sai
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
- School of Pharmacy, Inner Mongolia Medical University, 010110 Hohhot, China
| | - Wenping Wang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Mingyi Sun
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Rui Xu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yu Yao
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Zhiqin Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Changhai Qu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Xingbin Yin
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Jian Ni
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
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28
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Tan LX, Germer CJ, La Cunza N, Lakkaraju A. Complement activation, lipid metabolism, and mitochondrial injury: Converging pathways in age-related macular degeneration. Redox Biol 2020; 37:101781. [PMID: 33162377 PMCID: PMC7767764 DOI: 10.1016/j.redox.2020.101781] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/22/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
The retinal pigment epithelium (RPE) is the primary site of injury in non-neovascular age-related macular degeneration or dry AMD. Polymorphisms in genes that regulate complement activation and cholesterol metabolism are strongly associated with AMD, but the biology underlying disease-associated variants is not well understood. Here, we highlight recent studies that have used molecular, biochemical, and live-cell imaging methods to elucidate mechanisms by which aging-associated insults conspire with AMD genetic risk variants to tip the balance towards disease. We discuss how critical functions including lipid metabolism, autophagy, complement regulation, and mitochondrial dynamics are compromised in the RPE, and how a deeper understanding of these mechanisms has helped identify promising therapeutic targets to preserve RPE homeostasis in AMD.
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Affiliation(s)
- Li Xuan Tan
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA
| | - Colin J Germer
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA
| | - Nilsa La Cunza
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA
| | - Aparna Lakkaraju
- Department of Ophthalmology, School of Medicine, University of California, San Francisco, CA, USA; Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, CA, USA; Department of Anatomy, School of Medicine, University of California, San Francisco, CA, USA.
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29
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Storm T, Burgoyne T, Futter CE. Membrane trafficking in the retinal pigment epithelium at a glance. J Cell Sci 2020; 133:133/16/jcs238279. [PMID: 32855284 DOI: 10.1242/jcs.238279] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a highly specialised pigmented monolayer sandwiched between the choroid and the photoreceptors in the retina. Key functions of the RPE include transport of nutrients to the neural retina, removal of waste products and water from the retina to the blood, recycling of retinal chromophores, absorption of scattered light and phagocytosis of the tips of the photoreceptor outer segments. These functions place a considerable membrane trafficking burden on the RPE. In this Cell Science at a Glance article and the accompanying poster, we focus on RPE-specific adaptations of trafficking pathways. We outline mechanisms underlying the polarised expression of membrane proteins, melanosome biogenesis and movement, and endocytic trafficking, as well as photoreceptor outer segment phagocytosis and degradation. We also briefly discuss theories of how dysfunction in trafficking pathways contributes to retinal disease.
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Affiliation(s)
- Tina Storm
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Clare E Futter
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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30
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Pollreisz A, Neschi M, Sloan KR, Pircher M, Mittermueller T, Dacey DM, Schmidt-Erfurth U, Curcio CA. Atlas of Human Retinal Pigment Epithelium Organelles Significant for Clinical Imaging. Invest Ophthalmol Vis Sci 2020; 61:13. [PMID: 32648890 PMCID: PMC7425708 DOI: 10.1167/iovs.61.8.13] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/27/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose To quantify organelles impacting imaging in the cell body and intact apical processes of human retinal pigment epithelium (RPE), including melanosomes, lipofuscin-melanolipofuscin (LM), mitochondria, and nuclei. Methods A normal perifovea of a 21-year-old white male was preserved after rapid organ recovery. An aligned image stack was generated using serial block-face scanning electron microscopy and was annotated by expert readers (TrakEM, ImageJ). Acquired measures included cell body and nuclear volume (n = 17); organelle count in apical processes (n = 17) and cell bodies (n = 8); distance of cell body organelles along a normalized apical-basal axis (n = 8); and dimensions of organelle-bounding boxes in apical processes in selected subsamples of cell bodies and apical processes. Results In 2661 sections through 17 cells, apical processes contained 65 ± 24 melanosomes in mononucleate (n = 15) and 131 ± 28 in binucleate cells (n = 2). Cell bodies contained 681 ± 153 LM and 734 ± 170 mitochondria. LM was excluded from the basal quartile, and mitochondria from the apical quartile. Lengths of melanosomes, LM, and mitochondria, respectively were 2305 ± 528, 1320 ± 574, and 1195 ± 294 nm. The ratio of cell body to nucleus volume was 4.6 ± 0.4. LM and mitochondria covered 75% and 63%, respectively, of the retinal imaging plane. Conclusions Among RPE signal sources for optical coherence tomography, LM and mitochondria are the most numerous reflective cell body organelles. These and our published data show that most melanosomes are in apical processes. Overlapping LM and previously mitochondria cushions may support multiple reflective bands in cell bodies. This atlas of subcellular reflectivity sources can inform development of advanced optical coherence tomography technologies.
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Affiliation(s)
- Andreas Pollreisz
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Martina Neschi
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Kenneth R. Sloan
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Computer Science, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Dennis M. Dacey
- Department of Biologic Structure, University of Washington, Seattle, Washington, United States
| | | | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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31
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Kaposi's Sarcoma-Associated Herpesvirus and Host Interaction by the Complement System. Pathogens 2020; 9:pathogens9040260. [PMID: 32260199 PMCID: PMC7237997 DOI: 10.3390/pathogens9040260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/19/2020] [Accepted: 04/02/2020] [Indexed: 12/31/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) modulates the immune response to allow the virus to establish persistent infection in the host and facilitate the development of KSHV-associated cancer. The complement system has a central role in the defense against pathogens. Hence, KSHV has adopted an evasion strategy for complement attack using the viral protein encoded by KSHV open reading frame 4. However, despite this defense mechanism, the complement system appears to become activated in KSHV-infected cells as well as in the region surrounding Kaposi’s sarcoma tumors. Given that the complement system can affect cell fate as well as the inflammatory microenvironment, complement activation is likely associated with KSHV pathogenesis. A better understanding of the interplay between KSHV and the complement system may, therefore, translate into the development of novel therapeutic interventions for KSHV-associated tumors. In this review, the mechanisms and functions of complement activation in KSHV-infected cells are discussed.
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Naso F, Intartaglia D, Falanga D, Soldati C, Polishchuk E, Giamundo G, Tiberi P, Marrocco E, Scudieri P, Di Malta C, Trapani I, Nusco E, Salierno FG, Surace EM, Galietta LJ, Banfi S, Auricchio A, Ballabio A, Medina DL, Conte I. Light-responsive microRNA miR-211 targets Ezrin to modulate lysosomal biogenesis and retinal cell clearance. EMBO J 2020; 39:e102468. [PMID: 32154600 DOI: 10.15252/embj.2019102468] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 12/16/2022] Open
Abstract
Vertebrate vision relies on the daily phagocytosis and lysosomal degradation of photoreceptor outer segments (POS) within the retinal pigment epithelium (RPE). However, how these events are controlled by light is largely unknown. Here, we show that the light-responsive miR-211 controls lysosomal biogenesis at the beginning of light-dark transitions in the RPE by targeting Ezrin, a cytoskeleton-associated protein essential for the regulation of calcium homeostasis. miR-211-mediated down-regulation of Ezrin leads to Ca2+ influx resulting in the activation of calcineurin, which in turn activates TFEB, the master regulator of lysosomal biogenesis. Light-mediated induction of lysosomal biogenesis and function is impaired in the RPE from miR-211-/- mice that show severely compromised vision. Pharmacological restoration of lysosomal biogenesis through Ezrin inhibition rescued the miR-211-/- phenotype, pointing to a new therapeutic target to counteract retinal degeneration associated with lysosomal dysfunction.
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Affiliation(s)
- Federica Naso
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | | | - Danila Falanga
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Chiara Soldati
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Giuliana Giamundo
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Paola Tiberi
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Paolo Scudieri
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Chiara Di Malta
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Ivana Trapani
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Edoardo Nusco
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | | | - Enrico Maria Surace
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Department of Translational Medicine, University of Naples Federico II, Naples, Italy
| | - Luis Jv Galietta
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Department of Translational Medicine, University of Naples Federico II, Naples, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, University of Campania "L. Vanvitelli", Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Department of Translational Medicine, University of Naples Federico II, Naples, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Department of Translational Medicine, University of Naples Federico II, Naples, Italy.,Jan and Dan Duncan Neurological Research Institute, Texas Children Hospital, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy.,Department of Biology, University of Naples Federico II, Naples, Italy
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33
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Lakkaraju A, Umapathy A, Tan LX, Daniele L, Philp NJ, Boesze-Battaglia K, Williams DS. The cell biology of the retinal pigment epithelium. Prog Retin Eye Res 2020; 78:100846. [PMID: 32105772 PMCID: PMC8941496 DOI: 10.1016/j.preteyeres.2020.100846] [Citation(s) in RCA: 185] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE), a monolayer of post-mitotic polarized epithelial cells, strategically situated between the photoreceptors and the choroid, is the primary caretaker of photoreceptor health and function. Dysfunction of the RPE underlies many inherited and acquired diseases that cause permanent blindness. Decades of research have yielded valuable insight into the cell biology of the RPE. In recent years, new technologies such as live-cell imaging have resulted in major advancement in our understanding of areas such as the daily phagocytosis and clearance of photoreceptor outer segment tips, autophagy, endolysosome function, and the metabolic interplay between the RPE and photoreceptors. In this review, we aim to integrate these studies with an emphasis on appropriate models and techniques to investigate RPE cell biology and metabolism, and discuss how RPE cell biology informs our understanding of retinal disease.
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Affiliation(s)
- Aparna Lakkaraju
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Ankita Umapathy
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Li Xuan Tan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Lauren Daniele
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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34
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Keeling E, Chatelet DS, Johnston DA, Page A, Tumbarello DA, Lotery AJ, Ratnayaka JA. Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE). Mol Nutr Food Res 2019; 63:e1800951. [PMID: 30835933 DOI: 10.1002/mnfr.201800951] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/18/2019] [Indexed: 12/19/2022]
Abstract
SCOPE Oxidative stress and dysregulated intracellular trafficking are associated with an unhealthy diet which underlies pathology. Here, these effects on photoreceptor outer segment (POS) trafficking in the retinal pigment epithelium (RPE), a major pathway of disease underlying irreversible sight-loss, are studied. METHODS AND RESULTS POS trafficking is studied in ARPE-19 cells using an algorithm-based quantification of confocal-immunofluorescence data supported by ultrastructural studies. It is shown that although POS are tightly regulated and trafficked via Rab5, Rab7 vesicles, LAMP1/2 lysosomes and LC3b-autophagosomes, there is also a considerable degree of variation and flexibility in this process. Treatment with H2 O2 and bafilomycin A1 reveals that oxidative stress and dysregulated autophagy target intracellular compartments and trafficking in strikingly different ways. These effects appear limited to POS-containing vesicles, suggesting a cargo-specific effect. CONCLUSION The findings offer insights into how RPE cells cope with stress, and how mechanisms influencing POS transport/degradation can have different outcomes in the senescent retina. These shed new light on cellular processes underlying retinopathies such as age-related macular degeneration. The discoveries reveal how diet and nutrition can cause fundamental alterations at a cellular level, thus contributing to a better understanding of the diet-disease axis.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
| | - David S Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Life Sciences Building 85, SO17 1BJ, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
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35
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Control of growth factor signalling by MACPF proteins. Biochem Soc Trans 2019; 47:801-810. [PMID: 31209154 DOI: 10.1042/bst20180179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/17/2019] [Accepted: 05/28/2019] [Indexed: 11/17/2022]
Abstract
Members of the membrane attack complex/perforin-like (MACPF) protein superfamily have long captured interest because of their unique ability to assemble into large oligomeric pores on the surfaces of cells. The best characterised of these act in vertebrate immunity where they function to deliver pro-apoptotic factors or induce the cytolysis and death of targeted cells. Less appreciated, however, is that rather than causing cell death, MACPF proteins have also evolved to control cellular signalling pathways and influence developmental programmes such as pattern formation and neurogenesis. Torso-like (Tsl) from the fruit fly Drosophila, for example, functions to localise the activity of a growth factor for patterning its embryonic termini. It remains unclear whether these developmental proteins employ an attenuated form of the classical MACPF lytic pore, or if they have evolved to function via alternative mechanisms of action. In this minireview, we examine the evidence that links pore-forming MACPF proteins to the control of growth factor and cytokine signalling. We will then attempt to reconcile how the MACPF domain may have been repurposed during evolution for developmental events rather than cell killing.
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Kumar-Singh R. The role of complement membrane attack complex in dry and wet AMD - From hypothesis to clinical trials. Exp Eye Res 2019; 184:266-277. [PMID: 31082363 DOI: 10.1016/j.exer.2019.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/06/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022]
Abstract
Data from human dry and wet age-related macular degeneration (AMD) eyes support the hypothesis that constant 'tickover' of the alternative complement pathway results in chronic deposition of the complement membrane attack complex (MAC) on the choriocapillaris and the retinal pigment epithelium (RPE). Sub-lytic levels of MAC lead to cell signaling associated with tissue remodeling and the production of cytokines and inflammatory molecules. Lytic levels of MAC lead to cell death. CD59 is a naturally occurring inhibitor of the assembly of MAC. CD59 may thus be therapeutically efficacious against the pathophysiology of dry and wet AMD. The first gene therapy clinical trial for geographic atrophy - the advanced form of dry AMD has recently completed recruitment. This trial is studying the safety and tolerability of expressing CD59 from an adeno-associated virus (AAV) vector injected once into the vitreous. A second clinical trial assessing the efficacy of CD59 in wet AMD patients is also under way. Herein, the evidence for the role of MAC in the pathophysiology of dry as well as wet AMD and the scientific rationale underlying the use of AAV- delivered CD59 for the treatment of dry and wet AMD is discussed.
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Affiliation(s)
- Rajendra Kumar-Singh
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA.
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37
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Role of Bioactive Sphingolipids in Inflammation and Eye Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1161:149-167. [PMID: 31562629 DOI: 10.1007/978-3-030-21735-8_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inflammation is a common underlying factor in a diversity of ocular diseases, ranging from macular degeneration, autoimmune uveitis, glaucoma, diabetic retinopathy and microbial infection. In addition to the variety of known cellular mediators of inflammation, such as cytokines, chemokines and lipid mediators, there is now considerable evidence that sphingolipid metabolites also play a central role in the regulation of inflammatory pathways. Various sphingolipid metabolites, such as ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and lactosylceramide (LacCer) can contribute to ocular inflammatory diseases through multiple pathways. For example, inflammation generates Cer from sphingomyelins (SM) in the plasma membrane, which induces death receptor ligand formation and leads to apoptosis of retinal pigment epithelial (RPE) and photoreceptor cells. Inflammatory stress by reactive oxygen species leads to LacCer accumulation and S1P secretion and induces proliferation of retinal endothelial cells and eventual formation of new vessels. In sphingolipid/lysosomal storage disorders, sphingolipid metabolites accumulate in lysosomes and can cause ocular disorders that have an inflammatory etiology. Sphingolipid metabolites activate complement factors in the immune-response mediated pathogenesis of macular degeneration. These examples highlight the integral association between sphingolipids and inflammation in ocular diseases.
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38
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Inflammatory Ocular Diseases and Sphingolipid Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1159:139-152. [DOI: 10.1007/978-3-030-21162-2_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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39
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Aberrant early endosome biogenesis mediates complement activation in the retinal pigment epithelium in models of macular degeneration. Proc Natl Acad Sci U S A 2018; 115:9014-9019. [PMID: 30126999 DOI: 10.1073/pnas.1805039115] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abnormally enlarged early endosomes (EEs) are pathological features of neurodegenerative diseases, yet insight into the mechanisms and consequences of EE expansion remains elusive. Here, we report swollen apical EEs in the retinal pigment epithelium (RPE) of aged human donors and in the pigmented Abca4-/- mouse model of Stargardt early-onset macular degeneration. Using high-resolution live-cell imaging, we show that age-related and pathological accumulation of lipofuscin bisretinoids increases ceramide at the apical surface of the RPE, which promotes inward budding and homotypic fusion of EEs. These enlarged endosomes internalize the complement protein C3 into the RPE, resulting in the intracellular generation of C3a fragments. Increased C3a in turn activates the mechanistic target of rapamycin (mTOR), a regulator of critical metabolic processes such as autophagy. The antidepressant desipramine, which decreases ceramide levels by inhibiting acid sphingomyelinase, corrects EE defects in the RPE of Abca4-/- mice. This prevents C3 internalization and limits the formation of C3a fragments within the RPE. Although uncontrolled complement activation is associated with macular degenerations, how complement contributes to pathology in a progressive disease is not well understood. Our studies link expansion of the EE compartment with intracellular complement generation and aberrant mTOR activation, which could set the stage for chronic metabolic reprogramming in the RPE as a prelude to disease. The pivotal role of ceramide in driving EE biogenesis and fusion in the Abca4-/- mice RPE suggests that therapeutic targeting of ceramide could be effective in Stargardt disease and other macular degenerations.
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40
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Hollborn M, Ackmann C, Kuhrt H, Doktor F, Kohen L, Wiedemann P, Bringmann A. Osmotic and hypoxic induction of the complement factor C9 in cultured human retinal pigment epithelial cells: Regulation of VEGF and NLRP3 expression. Mol Vis 2018; 24:518-535. [PMID: 30090015 PMCID: PMC6066273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 07/26/2018] [Indexed: 11/06/2022] Open
Abstract
Purpose Variants of complement factor genes, hypoxia and oxidative stress of the outer retina, and systemic hypertension affect the risk of age-related macular degeneration. Hypertension often results from the high intake of dietary salt that increases extracellular osmolarity. We determined the effects of extracellular hyperosmolarity, hypoxia, and oxidative stress on the expression of complement genes in cultured (dedifferentiated) human RPE cells and investigated the effects of C9 siRNA and C9 protein on RPE cells. Methods Hyperosmolarity was induced by adding 100 mM NaCl or sucrose to the culture medium. Hypoxia was induced by culturing cells in 1% O2 or by adding the hypoxia mimetic CoCl2. Oxidative stress was induced by adding H2O2. Gene and protein expression levels were determined with real-time RT-PCR, western blot, and ELISA analyses. The expression of the nuclear factor of activated T cell 5 (NFAT5) and complement factor (C9) was knocked down with siRNA. Results Extracellular hyperosmolarity, hypoxia, and oxidative stress strongly increased the transcription of the C9 gene, while the expression of the C3, C5, CFH, and CFB genes was moderately altered or not altered at all. Hyperosmolarity also induced a moderate increase in the cytosolic C9 protein level. The hyperosmotic C9 gene expression was reduced by inhibitors of the p38 MAPK, ERK1/2, JNK, and PI3K signal transduction pathways and of the transcription factors STAT3 and NFAT5. The hypoxic C9 gene expression was reduced by a STAT3 inhibitor. The knockdown of C9 with siRNA decreased the hypoxic vascular endothelial growth factor (VEGF) and NLRP3 gene expression, the hypoxic secretion of VEGF, and the hyperosmotic expression of the NLRP3 gene. Exogenous C9 protein inhibited the hyperosmotic expression of the C9 gene, the hypoxic and hyperosmotic VEGF gene expression, and the hyperosmotic expression of the NLRP3 gene. Both C9 siRNA and C9 protein inhibited inflammasome activation under hyperosmotic conditions, as indicated by the decrease in the cytosolic level of mature IL-1β. Conclusions The expression of the C9 gene in cultured RPE cells is highly induced by extracellular hyperosmolarity, hypoxia, and oxidative stress. The data may support the assumption that C9 gene expression may stimulate the expression of inflammatory (NLRP3) and angiogenic growth factors (VEGF) in RPE cells. Extracellular C9 protein may attenuate this effect, in part via negative regulation of the C9 mRNA level.
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Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Charlotte Ackmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, University of Leipzig, Germany
| | - Fabian Doktor
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany,Helios Klinikum Aue, Aue, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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41
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Copland DA, Theodoropoulou S, Liu J, Dick AD. A Perspective of AMD Through the Eyes of Immunology. ACTA ACUST UNITED AC 2018; 59:AMD83-AMD92. [DOI: 10.1167/iovs.18-23893] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- David A. Copland
- Translational Health Sciences (Ophthalmology), University of Bristol, Bristol, United Kingdom
- National Institute for Health Research Biomedical Research Centre of Ophthalmology, Moorfields Eye Hospital and University College London-Institute of Ophthalmology, London, United Kingdom
| | - Sofia Theodoropoulou
- Translational Health Sciences (Ophthalmology), University of Bristol, Bristol, United Kingdom
- Bristol Eye Hospital, Bristol, United Kingdom
| | - Jian Liu
- Translational Health Sciences (Ophthalmology), University of Bristol, Bristol, United Kingdom
| | - Andrew D. Dick
- Translational Health Sciences (Ophthalmology), University of Bristol, Bristol, United Kingdom
- National Institute for Health Research Biomedical Research Centre of Ophthalmology, Moorfields Eye Hospital and University College London-Institute of Ophthalmology, London, United Kingdom
- Bristol Eye Hospital, Bristol, United Kingdom
- University College London–Institute of Ophthalmology, London, United Kingdom
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42
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Biswas L, Zhou X, Dhillon B, Graham A, Shu X. Retinal pigment epithelium cholesterol efflux mediated by the 18 kDa translocator protein, TSPO, a potential target for treating age-related macular degeneration. Hum Mol Genet 2018; 26:4327-4339. [PMID: 28973423 DOI: 10.1093/hmg/ddx319] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 08/06/2017] [Indexed: 12/13/2022] Open
Abstract
Cholesterol accumulation beneath the retinal pigment epithelium (RPE) cells is supposed to contribute the pathogenesis of age-related macular degeneration (AMD). Cholesterol efflux genes (APOE and ABCA1) were identified as risk factors for AMD, although how cholesterol efflux influences accumulation of this lipid in sub-RPE deposits remains elusive. The 18 kDa translocator protein, TSPO, is a cholesterol-binding protein implicated in mitochondrial cholesterol transport. Here, we investigate the function of TSPO in cholesterol efflux from the RPE cells. We demonstrate in RPE cells that TSPO specific ligands promoted cholesterol efflux to acceptor (apo)lipoprotein and human serum, while loss of TSPO resulted in impaired cholesterol efflux. TSPO-/- RPE cells also had significantly increased production of reactive oxygen species (ROS) and upregulated expression of proinflammatory cytokines (IL-1β and TNFα). Cholesterol (oxidized LDL) uptake and accumulation were markedly increased in TSPO-/- RPE cells. Finally, in aged RPE cells, TSPO expression was reduced and cholesterol efflux impaired. These findings provide a new pharmacological concept to treat early AMD patients by stimulating cellular cholesterol removal with TSPO specific ligands or by overexpression of TSPO in RPE cells.
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Affiliation(s)
- Lincoln Biswas
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xinzhi Zhou
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Baljean Dhillon
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16?4SB, UK
| | - Annette Graham
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
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43
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Keeling E, Lotery AJ, Tumbarello DA, Ratnayaka JA. Impaired Cargo Clearance in the Retinal Pigment Epithelium (RPE) Underlies Irreversible Blinding Diseases. Cells 2018; 7:E16. [PMID: 29473871 PMCID: PMC5850104 DOI: 10.3390/cells7020016] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/20/2018] [Accepted: 02/22/2018] [Indexed: 01/09/2023] Open
Abstract
Chronic degeneration of the Retinal Pigment Epithelium (RPE) is a precursor to pathological changes in the outer retina. The RPE monolayer, which lies beneath the neuroretina, daily internalises and digests large volumes of spent photoreceptor outer segments. Impaired cargo handling and processing in the endocytic/phagosome and autophagy pathways lead to the accumulation of lipofuscin and pyridinium bis-retinoid A2E aggregates and chemically modified compounds such as malondialdehyde and 4-hydroxynonenal within RPE. These contribute to increased proteolytic and oxidative stress, resulting in irreversible damage to post-mitotic RPE cells and development of blinding conditions such as age-related macular degeneration, Stargardt disease and choroideremia. Here, we review how impaired cargo handling in the RPE results in their dysfunction, discuss new findings from our laboratory and consider how newly discovered roles for lysosomes and the autophagy pathway could provide insights into retinopathies. Studies of these dynamic, molecular events have also been spurred on by recent advances in optics and imaging technology. Mechanisms underpinning lysosomal impairment in other degenerative conditions including storage disorders, α-synuclein pathologies and Alzheimer's disease are also discussed. Collectively, these findings help transcend conventional understanding of these intracellular compartments as simple waste disposal bags to bring about a paradigm shift in the way lysosomes are perceived.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK.
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, Life Science Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
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44
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Early Endosome Morphology in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:335-343. [PMID: 29721961 DOI: 10.1007/978-3-319-75402-4_41] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Early endosomes are organelles that receive macromolecules and solutes from the extracellular environment. The major function of early endosomes is to sort these cargos into recycling and degradative compartments of the cell. Degradation of the cargo involves maturation of early endosomes into late endosomes, which, after acquisition of hydrolytic enzymes, form lysosomes. Endosome maturation involves recruitment of specific proteins and lipids to the early endosomal membrane, which drives changes in endosome morphology. Defects in early endosome maturation are generally accompanied by alterations in morphology, such as increase in volume and/or number. Enlarged early endosomes have been observed in Alzheimer's disease and Niemann Pick Disease type C, which also exhibit defects in endocytic sorting. This article discusses the mechanisms that regulate early endosome morphology and highlights the potential importance of endosome maturation in the retinal pigment epithelium.
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45
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Guziewicz KE, Sinha D, Gómez NM, Zorych K, Dutrow EV, Dhingra A, Mullins RF, Stone EM, Gamm DM, Boesze-Battaglia K, Aguirre GD. Bestrophinopathy: An RPE-photoreceptor interface disease. Prog Retin Eye Res 2017; 58:70-88. [PMID: 28111324 PMCID: PMC5441932 DOI: 10.1016/j.preteyeres.2017.01.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 11/17/2022]
Abstract
Bestrophinopathies, one of the most common forms of inherited macular degenerations, are caused by mutations in the BEST1 gene expressed in the retinal pigment epithelium (RPE). Both human and canine BEST1-linked maculopathies are characterized by abnormal accumulation of autofluorescent material within RPE cells and bilateral macular or multifocal lesions; however, the specific mechanism leading to the formation of these lesions remains unclear. We now provide an overview of the current state of knowledge on the molecular pathology of bestrophinopathies, and explore factors promoting formation of RPE-neuroretinal separations, using the first spontaneous animal model of BEST1-associated retinopathies, canine Best (cBest). Here, we characterize the nature of the autofluorescent RPE cell inclusions and report matching spectral signatures of RPE-associated fluorophores between human and canine retinae, indicating an analogous composition of endogenous RPE deposits in Best Vitelliform Macular Dystrophy (BVMD) patients and its canine disease model. This study also exposes a range of biochemical and structural abnormalities at the RPE-photoreceptor interface related to the impaired cone-associated microvillar ensheathment and compromised insoluble interphotoreceptor matrix (IPM), the major pathological culprits responsible for weakening of the RPE-neuroretina interactions, and consequently, formation of vitelliform lesions. These salient alterations detected at the RPE apical domain in cBest as well as in BVMD- and ARB-hiPSC-RPE model systems provide novel insights into the pathological mechanism of BEST1-linked disorders that will allow for development of critical outcome measures guiding therapeutic strategies for bestrophinopathies.
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Affiliation(s)
- Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA.
| | - Divya Sinha
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Néstor M Gómez
- Department of Anatomy & Cell Biology, School of Dental Medicine, University of Pennsylvania, PA 19104, USA
| | - Kathryn Zorych
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
| | - Emily V Dutrow
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
| | - Anuradha Dhingra
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, PA 19104, USA
| | - Robert F Mullins
- Department of Ophthalmology & Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Edwin M Stone
- Department of Ophthalmology & Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Gustavo D Aguirre
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, PA 19104, USA
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46
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Monés J, Garcia M, Biarnés M, Lakkaraju A, Ferraro L. Drusen Ooze: A Novel Hypothesis in Geographic Atrophy. Ophthalmol Retina 2017; 1:461-473. [PMID: 31047436 DOI: 10.1016/j.oret.2017.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/17/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To describe a subgroup of subjects with soft drusen associated with geographic atrophy (GA) and novel spectral-domain OCT (SD-OCT) findings consistent with presumed drusen leakage. We also propose a mechanism leading to GA progression in these patients. DESIGN A retrospective, observational cohort study. PARTICIPANTS Forty-eight eyes of 33 patients with soft drusen secondary to age-related macular degeneration (AMD). METHODS Drusen were evaluated with SD-OCT and retinal imaging to characterize the development of atrophy-associated drusen regression (drusen collapse) over a follow-up period of ≥18 months. MAIN OUTCOME MEASURES The presence of isoreflective dots at the outer retinal layers associated with retinal pigment epithelium (RPE) defects. Percentages of previously reported hyperreflective RPE, and hyperreflective dots (HRDs) were also determined. RESULTS Nineteen of 48 eyes (39.6%) showed a collapse of ≥1 druse during the follow-up period. Thirty-four foci of collapsed drusen were found to be associated with either isoreflective dots associated with RPE defects (32.4%), hyperreflectivity of the RPE (91.2%), or HRDs (79.4%). A post hoc showed the adjusted odds ratio of drusen collapse for isoreflective dots (65.8), for HRDs (6.0) or both (12.1). CONCLUSIONS In soft drusen progressing to subsequent atrophy, approximately 33% were associated with isoreflective dots and RPE defects. In addition, overlying hyperreflectivity of the RPE and HRDs were noted with high frequency. Presence of isoreflective dots, with or without HRDs, was associated with a strong risk of developing atrophy compared with drusen without these findings. We hypothesize that these isoreflective dots associated with RPE defects may be debris extruded from the soft drusen into the subretinal space, which we have termed "drusen ooze". Drusen ooze may activate the RPE apical surfaces, leading to a marked increase in phagocytosis/endocytosis of extracellular debris that eventually overwhelms the RPE capacity, and leads to RPE death, subsequent release of intracellular RPE material and thereby propagate a cycle of cellular death resulting in GA development and progression. Therapeutic targeting of drusen material, prior to its extrusion into the subretinal space and prior to irreversible damage to the RPE, might prevent or delay onset and progression of GA.
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Affiliation(s)
- Jordi Monés
- Institut de la Màcula, Centro Médico Teknon, Barcelona, Spain; Barcelona Màcula Foundation, Barcelona, Spain.
| | - Míriam Garcia
- Institut de la Màcula, Centro Médico Teknon, Barcelona, Spain; Barcelona Màcula Foundation, Barcelona, Spain
| | - Marc Biarnés
- Institut de la Màcula, Centro Médico Teknon, Barcelona, Spain; Barcelona Màcula Foundation, Barcelona, Spain
| | - Aparna Lakkaraju
- Department of Ophthalmology and Visual Sciences, McPherson Eye Research Institute, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Lucia Ferraro
- Institut de la Màcula, Centro Médico Teknon, Barcelona, Spain; Barcelona Màcula Foundation, Barcelona, Spain
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47
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The impact of oxidative stress and inflammation on RPE degeneration in non-neovascular AMD. Prog Retin Eye Res 2017; 60:201-218. [PMID: 28336424 DOI: 10.1016/j.preteyeres.2017.03.002] [Citation(s) in RCA: 478] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE) is a highly specialized, unique epithelial cell that interacts with photoreceptors on its apical side and with Bruch's membrane and the choriocapillaris on its basal side. Due to vital functions that keep photoreceptors healthy, the RPE is essential for maintaining vision. With aging and the accumulated effects of environmental stresses, the RPE can become dysfunctional and die. This degeneration plays a central role in age-related macular degeneration (AMD) pathobiology, the leading cause of blindness among the elderly in western societies. Oxidative stress and inflammation have both physiological and potentially pathological roles in RPE degeneration. Given the central role of the RPE, this review will focus on the impact of oxidative stress and inflammation on the RPE with AMD pathobiology. Physiological sources of oxidative stress as well as unique sources from photo-oxidative stress, the phagocytosis of photoreceptor outer segments, and modifiable factors such as cigarette smoking and high fat diet ingestion that can convert oxidative stress into a pathological role, and the negative impact of impairing the cytoprotective roles of mitochondrial dynamics and the Nrf2 signaling system on RPE health in AMD will be discussed. Likewise, the response by the innate immune system to an inciting trigger, and the potential role of local RPE production of inflammation, as well as a potential role for damage by inflammation with chronicity if the inciting trigger is not neutralized, will be debated.
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