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Sendecki A, Ledwoń D, Tuszy A, Nycz J, Wąsowska A, Boguszewska-Chachulska A, Wylęgała A, Mitas AW, Wylęgała E, Teper S. Association of Genetic Risk for Age-Related Macular Degeneration with Morphological Features of the Retinal Microvascular Network. Diagnostics (Basel) 2024; 14:770. [PMID: 38611684 PMCID: PMC11011905 DOI: 10.3390/diagnostics14070770] [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: 03/13/2024] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is a multifactorial disease encompassing a complex interaction between aging, environmental risk factors, and genetic susceptibility. The study aimed to determine whether there is a relationship between the polygenic risk score (PRS) in patients with AMD and the characteristics of the retinal vascular network visualized by optical coherence tomography angiography (OCTA). METHODS 235 patients with AMD and 97 healthy controls were included. We used data from a previous AMD PRS study with the same group. The vascular features from different retina layers were compared between the control group and the patients with AMD. The association between features and PRS was then analyzed using univariate and multivariate approaches. RESULTS Significant differences between the control group and AMD patients were found in the vessel diameter distribution (variance: p = 0.0193, skewness: p = 0.0457) and fractal dimension distribution (mean: p = 0.0024, variance: p = 0.0123). Both univariate and multivariate analyses showed no direct and significant association between the characteristics of the vascular network and AMD PRS. CONCLUSIONS The vascular features of the retina do not constitute a biomarker of the risk of AMD. We have not identified a genotype-phenotype relationship, and the expression of AMD-related genes is perhaps not associated with the characteristics of the retinal vascular network.
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Affiliation(s)
- Adam Sendecki
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-752 Katowice, Poland; (A.S.); (A.W.); (A.W.); (E.W.); (S.T.)
| | - Daniel Ledwoń
- Faculty of Biomedical Engineering, Silesian University of Technology, 41-800 Zabrze, Poland; (A.T.); (A.W.M.)
| | - Aleksandra Tuszy
- Faculty of Biomedical Engineering, Silesian University of Technology, 41-800 Zabrze, Poland; (A.T.); (A.W.M.)
| | - Julia Nycz
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, 98693 Ilmenau, Germany;
| | - Anna Wąsowska
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-752 Katowice, Poland; (A.S.); (A.W.); (A.W.); (E.W.); (S.T.)
- Genomed S.A., 02-971 Warszawa, Poland;
| | | | - Adam Wylęgała
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-752 Katowice, Poland; (A.S.); (A.W.); (A.W.); (E.W.); (S.T.)
| | - Andrzej W. Mitas
- Faculty of Biomedical Engineering, Silesian University of Technology, 41-800 Zabrze, Poland; (A.T.); (A.W.M.)
| | - Edward Wylęgała
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-752 Katowice, Poland; (A.S.); (A.W.); (A.W.); (E.W.); (S.T.)
| | - Sławomir Teper
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-752 Katowice, Poland; (A.S.); (A.W.); (A.W.); (E.W.); (S.T.)
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2
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Bullock KK, Shattuck-Brandt R, Scalise C, Luo W, Chen SC, Saleh N, Gonzalez-Ericsson PI, Garcia G, Sanders ME, Ayers GD, Yan C, Richmond A. Endogenous pAKT activity is associated with response to AKT inhibition alone and in combination with immune checkpoint inhibition in murine models of TNBC. Cancer Lett 2024; 586:216681. [PMID: 38311054 DOI: 10.1016/j.canlet.2024.216681] [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: 11/06/2023] [Revised: 12/22/2023] [Accepted: 01/25/2024] [Indexed: 02/06/2024]
Abstract
Triple-negative breast cancer (TNBC) is a heterogeneous and challenging-to-treat breast cancer subtype. The clinical introduction of immune checkpoint inhibitors (ICI) for TNBC has had mixed results, and very few patients achieved a durable response. The PI3K/AKT pathway is frequently mutated in breast cancer. Given the important roles of the PI3K pathway in immune and tumor cell signaling, there is an interest in using inhibitors of this pathway to increase the response to ICI. This study sought to determine if AKT inhibition could enhance the response to ICI in murine TNBC models. We further sought to understand underlying mechanisms of response or non-response to AKT inhibition in combination with ICI. Using four murine TNBC-like cell lines and corresponding orthotopic mouse tumor models, we found that hyperactivity of the PI3K pathway, as evidenced by levels of phospho-AKT rather than PI3K pathway mutational status, was associated with response to AKT inhibition alone and in combination with ICI. Additional mutations in other growth regulatory pathways could override the response of PI3K pathway mutant tumors to AKT inhibition. Furthermore, we observed that AKT inhibition enhanced the response to ICI in an already sensitive model. However, AKT inhibition failed to convert ICI-resistant tumors, to responsive tumors. These findings suggest that analysis of both the mutational status and phospho-AKT protein levels may be beneficial in predicting which TNBC tumors will respond to AKT inhibition in combination with ICI.
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Affiliation(s)
- Kennady K Bullock
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Rebecca Shattuck-Brandt
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Carly Scalise
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Weifeng Luo
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Sheau-Chiann Chen
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nabil Saleh
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Paula I Gonzalez-Ericsson
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Guadalupe Garcia
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Melinda E Sanders
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gregory D Ayers
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Chi Yan
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA.
| | - Ann Richmond
- Tennessee Valley Healthcare System, Department of Veteran Affairs, Nashville, TN, USA; Department of Pharmacology, Vanderbilt School of Medicine, Nashville, TN, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA.
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Kocherlakota S, Baes M. Benefits and Caveats in the Use of Retinal Pigment Epithelium-Specific Cre Mice. Int J Mol Sci 2024; 25:1293. [PMID: 38279294 PMCID: PMC10816505 DOI: 10.3390/ijms25021293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/28/2024] Open
Abstract
The retinal pigment epithelium (RPE) is an important monolayer of cells present in the outer retina, forming a major part of the blood-retina barrier (BRB). It performs many tasks essential for the maintenance of retinal integrity and function. With increasing knowledge of the retina, it is becoming clear that both common retinal disorders, like age-related macular degeneration, and rare genetic disorders originate in the RPE. This calls for a better understanding of the functions of various proteins within the RPE. In this regard, mice enabling an RPE-specific gene deletion are a powerful tool to study the role of a particular protein within the RPE cells in their native environment, simultaneously negating any potential influences of systemic changes. Moreover, since RPE cells interact closely with adjacent photoreceptors, these mice also provide an excellent avenue to study the importance of a particular gene function within the RPE to the retina as a whole. In this review, we outline and compare the features of various Cre mice created for this purpose, which allow for inducible or non-inducible RPE-specific knockout of a gene of interest. We summarize the various benefits and caveats involved in the use of such mouse lines, allowing researchers to make a well-informed decision on the choice of Cre mouse to use in relation to their research needs.
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Affiliation(s)
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
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Bernardo-Colón A, Dong L, Abu-Asab M, Brush RS, Agbaga MP, Becerra SP. Ablation of pigment epithelium-derived factor receptor (PEDF-R/Pnpla2) causes photoreceptor degeneration. J Lipid Res 2023; 64:100358. [PMID: 36934843 PMCID: PMC10233210 DOI: 10.1016/j.jlr.2023.100358] [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: 12/14/2022] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023] Open
Abstract
Photoreceptor cells express the patatin-like phospholipase domain-containing 2 (PNPLA2) gene that codes for pigment epithelium-derived factor receptor (PEDF-R) (also known as ATGL). PEDF-R exhibits phospholipase activity that mediates the neurotrophic action of its ligand PEDF. Because phospholipids are the most abundant lipid class in the retina, we investigated the role of PEDF-R in photoreceptors by generating CRISPR Pnpla2 knock-out mouse lines in a retinal degeneration-free background. Pnpla2-/- mice had undetectable retinal Pnpla2 gene expression and PEDF-R protein levels as assayed by RT-PCR and immunofluorescence, respectively. The photoreceptors of mice deficient in PEDF-R had deformities as examined by histology and transmission electron microscopy. Pnpla2 knockdown diminished the PLA2 enzymatic activity of PEDF-R in the retina. Lipidomic analyses revealed the accumulation of lysophosphatidyl choline-DHA and lysophosphatidyl ethanolamine-DHA in PEDF-R-deficient retinas, suggesting a possible causal link to photoreceptor dysfunction. Loss of PEDF-R decreased levels of rhodopsin, opsin, PKCα, and synaptophysin relative to controls. Pnpla2-/- photoreceptors had surface-exposed phosphatidylserine, and their nuclei were TUNEL positive and condensed, revealing an apoptotic onset. Paralleling its structural defects, PEDF-R deficiency compromised photoreceptor function in vivo as indicated by the attenuation of photoreceptor a- and b-waves in Pnpla2-/- and Pnpla2+/- mice relative to controls as determined by electroretinography. In conclusion, ablation of PEDF-R in mice caused alteration in phospholipid composition associated with malformation and malperformance of photoreceptors. These findings identify PEDF-R as an important component for photoreceptor structure and function, highlighting its role in phospholipid metabolism for retinal survival and its consequences.
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Affiliation(s)
- Alexandra Bernardo-Colón
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mones Abu-Asab
- Histopathology Core Facility, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Richard S Brush
- Department of Ophthalmology(,) and Dean A. McGee Eye Institute, Oklahoma City, OK, USA
| | - Martin-Paul Agbaga
- Department of Ophthalmology(,) and Dean A. McGee Eye Institute, Oklahoma City, OK, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - S Patricia Becerra
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
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5
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Hara M, Wu W, Malechka VV, Takahashi Y, Ma JX, Moiseyev G. PNPLA2 mobilizes retinyl esters from retinosomes and promotes the generation of 11-cis-retinal in the visual cycle. Cell Rep 2023; 42:112091. [PMID: 36763501 PMCID: PMC10406976 DOI: 10.1016/j.celrep.2023.112091] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/22/2022] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Abstract
Retinosomes are intracellular lipid bodies found in the retinal pigment epithelium (RPE). They contain retinyl esters (REs) and are thought to be involved in visual chromophore regeneration during dark adaptation and in case of chromophore depletion. However, key enzymes in chromophore regeneration, retinoid isomerase (RPE65), and lecithin:retinol acyltransferase (LRAT) are located in the endoplasmic reticulum (ER). The mechanism and the enzyme responsible for mobilizing REs from retinosomes remained unknown. Our study demonstrates that patatin-like phospholipase domain containing 2 (PNPLA2) mobilizes all-trans-REs from retinosomes. The absence of PNPLA2 in mouse eyes leads to a significant accumulation of lipid droplets in RPE cells, declined electroretinography (ERG) response, and delayed dark adaptation compared with those of WT control mouse. Our work suggests a function of PNPLA2 as an RE hydrolase in the RPE, mobilizing REs from lipid bodies and functioning as an essential component of the visual cycle.
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Affiliation(s)
- Miwa Hara
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, NC 27157, USA
| | - Wenjing Wu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, NC 27157, USA
| | - Volha V Malechka
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Yusuke Takahashi
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, NC 27157, USA
| | - Jian-Xing Ma
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, NC 27157, USA
| | - Gennadiy Moiseyev
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, NC 27157, USA.
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Bernardo-Colón A, Lerner M, Becerra SP. Pigment epithelium-derived factor is an interleukin-6 antagonist in the RPE: Insight of structure-function relationships. Front Physiol 2022; 13:1045613. [PMID: 36467689 PMCID: PMC9709256 DOI: 10.3389/fphys.2022.1045613] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/03/2022] [Indexed: 07/04/2024] Open
Abstract
Retinal and choroidal inflammatory lesions increase the levels of the pro-inflammatory cytokine interleukin-6 (IL-6). Pigment epithelium-derived factor (PEDF) has anti-inflammatory properties, but it is not known if it can prevent the production of IL-6 by the retinal pigment epithelium. To investigate the anti-inflammatory effects of PEDF in the RPE, we used human ARPE-19 cells stimulated with human recombinant tumor necrosis factor-alpha (TNF-α) to induce overexpression of the IL6 gene. We found that the viability of ARPE-19 cells decreased by 22% with TNF-α at 10 ng/ml, being drastically decreased at ≥50 ng/ml. TNF-α at 5-100 ng/ml elevated the production and secretion of IL-6 protein, as measured by ELISA. To challenge the TNF-α-mediated stimulation of IL-6, we used recombinant human PEDF protein. PEDF at 100 nM recovered the TNF-α-mediated loss of cell viability and repressed IL-6 gene expression as determined by RT-PCR. PEDF at 10-100 nM attenuated the IL-6 protein secretion in a dose dependent fashion (IC50 = 65 nM), being abolished with 100 nM PEDF. To map the region that confers the IL-6 blocking effect to the PEDF polypeptide, we used chemically synthesized peptides designed from its biologically active domains, pro-death 34-mer, and pro-survival 44-mer and 17-mer (H105A), to challenge the IL-6 overproduction. The pro-survival peptides recovered the TNF-α-mediated cell viability loss, and inhibited IL-6 secretion, while the 34-mer did not have an effect, suggesting a role for the pro-survival domain in blocking TNF-α-mediated cell death and IL-6 stimulation. Our findings position PEDF as a novel antagonistic agent of IL-6 production in RPE cells, underscoring its use for the management of retinal disease-related inflammation.
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Affiliation(s)
| | | | - S. Patricia Becerra
- Laboratory of Retinal Cell and Molecular Biology, Section of Protein Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
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The retinal pigmentation pathway in human albinism: Not so black and white. Prog Retin Eye Res 2022; 91:101091. [PMID: 35729001 DOI: 10.1016/j.preteyeres.2022.101091] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Albinism is a pigment disorder affecting eye, skin and/or hair. Patients usually have decreased melanin in affected tissues and suffer from severe visual abnormalities, including foveal hypoplasia and chiasmal misrouting. Combining our data with those of the literature, we propose a single functional genetic retinal signalling pathway that includes all 22 currently known human albinism disease genes. We hypothesise that defects affecting the genesis or function of different intra-cellular organelles, including melanosomes, cause syndromic forms of albinism (Hermansky-Pudlak (HPS) and Chediak-Higashi syndrome (CHS)). We put forward that specific melanosome impairments cause different forms of oculocutaneous albinism (OCA1-8). Further, we incorporate GPR143 that has been implicated in ocular albinism (OA1), characterised by a phenotype limited to the eye. Finally, we include the SLC38A8-associated disorder FHONDA that causes an even more restricted "albinism-related" ocular phenotype with foveal hypoplasia and chiasmal misrouting but without pigmentation defects. We propose the following retinal pigmentation pathway, with increasingly specific genetic and cellular defects causing an increasingly specific ocular phenotype: (HPS1-11/CHS: syndromic forms of albinism)-(OCA1-8: OCA)-(GPR143: OA1)-(SLC38A8: FHONDA). Beyond disease genes involvement, we also evaluate a range of (candidate) regulatory and signalling mechanisms affecting the activity of the pathway in retinal development, retinal pigmentation and albinism. We further suggest that the proposed pigmentation pathway is also involved in other retinal disorders, such as age-related macular degeneration. The hypotheses put forward in this report provide a framework for further systematic studies in albinism and melanin pigmentation disorders.
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Blasiak J, Kaarniranta K. Secretory autophagy: a turn key for understanding AMD pathology and developing new therapeutic targets? Expert Opin Ther Targets 2022; 26:883-895. [PMID: 36529978 DOI: 10.1080/14728222.2022.2157260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Age-related macular degeneration (AMD) is an eye disease leading to vision loss with poorly known pathogenesis and limited therapeutic options. Degradative autophagy (DA) is impaired in AMD, but emerging evidence points to secretary autophagy (SA) as a key element in AMD pathogenesis. AREAS COVERED SA may cause the release of proteins and protein aggregates, lipofuscin, beta amyloid, faulty mitochondria, pro-inflammatory and pro-angiogenic factors from the retinal pigment epithelium (RPE) that may contribute to drusen formation and choroidal neovascularization. SA may replace DA, when formation of autolysosome is impaired, and then a harmful cargo, instead of being degraded, is extruded from the RPE contributing to drusen and/or angiogenic environment. Therefore, the interplay between DA and SA may be critical for drusen formation and choroidal neovascularization, so it can be a turn key to understand AMD pathogenesis. EXPERT OPINION Although SA fulfills some beneficial functions, it is detrimental for the retina in many cases. Therefore, inhibiting SA may be a therapeutic strategy in AMD, but it is challenged by the development of selective SA inhibitors that would not affect DA. The TRIM16, SEC22B and RAB8A proteins, specific for secretory autophagosome, may be primary candidates as therapeutic targets, but their action is not limited to autophagy and therefore requires further studies.
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Affiliation(s)
- Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Lodz, Poland
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, Kuopio, Finland.,Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
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Rebustini IT, Crawford SE, Becerra SP. PEDF Deletion Induces Senescence and Defects in Phagocytosis in the RPE. Int J Mol Sci 2022; 23:7745. [PMID: 35887093 PMCID: PMC9316002 DOI: 10.3390/ijms23147745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 02/01/2023] Open
Abstract
The retinal pigment epithelium (RPE) expresses the Serpinf1 gene to produce pigment epithelium-derived factor (PEDF), a retinoprotective protein that is downregulated with cell senescence, aging and retinal degenerations. We determined the expression of senescence-associated genes in the RPE of 3-month-old mice that lack the Serpinf1 gene and found that Serpinf1 deletion induced H2ax for histone H2AX protein, Cdkn1a for p21 protein, and Glb1 gene for β-galactosidase. Senescence-associated β-galactosidase activity increased in the Serpinf1 null RPE when compared with wild-type RPE. We evaluated the subcellular morphology of the RPE and found that ablation of Serpinf1 increased the volume of the nuclei and the nucleoli number of RPE cells, implying chromatin reorganization. Given that the RPE phagocytic function declines with aging, we assessed the expression of the Pnpla2 gene, which is required for the degradation of photoreceptor outer segments by the RPE. We found that both the Pnpla2 gene and its protein PEDF-R declined with the Serpinf1 gene ablation. Moreover, we determined the levels of phagocytosed rhodopsin and lipids in the RPE of the Serpinf1 null mice. The RPE of the Serpinf1 null mice accumulated rhodopsin and lipids compared to littermate controls, implying an association of PEDF deficiency with RPE phagocytosis dysfunction. Our findings establish PEDF loss as a cause of senescence-like changes in the RPE, highlighting PEDF as both a retinoprotective and a regulatory protein of aging-like changes associated with defective degradation of the photoreceptor outer segment in the RPE.
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Affiliation(s)
- Ivan T. Rebustini
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Susan E. Crawford
- Department of Surgery, North Shore University Research Institute, University of Chicago Pritzker School of Medicine, Chicago, IL 60201, USA;
| | - S. Patricia Becerra
- Section of Protein Structure and Function, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA;
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Flores‐Bellver M, Mighty J, Aparicio‐Domingo S, Li KV, Shi C, Zhou J, Cobb H, McGrath P, Michelis G, Lenhart P, Bilousova G, Heissel S, Rudy MJ, Coughlan C, Goodspeed AE, Becerra SP, Redenti S, Canto‐Soler MV. Extracellular vesicles released by human retinal pigment epithelium mediate increased polarised secretion of drusen proteins in response to AMD stressors. J Extracell Vesicles 2021; 10:e12165. [PMID: 34750957 PMCID: PMC8575963 DOI: 10.1002/jev2.12165] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/06/2021] [Accepted: 10/25/2021] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. Drusen are key contributors to the etiology of AMD and the ability to modulate drusen biogenesis could lead to therapeutic strategies to slow or halt AMD progression. The mechanisms underlying drusen biogenesis, however, remain mostly unknown. Here we demonstrate that under homeostatic conditions extracellular vesicles (EVs) secreted by retinal pigment epithelium (RPE) cells are enriched in proteins associated with mechanisms involved in AMD pathophysiology, including oxidative stress, immune response, inflammation, complement system and drusen composition. Furthermore, we provide first evidence that drusen-associated proteins are released as cargo of extracellular vesicles secreted by RPE cells in a polarised apical:basal mode. Notably, drusen-associated proteins exhibited distinctive directional secretion modes in homeostatic conditions and, differential modulation of this directional secretion in response to AMD stressors. These observations underpin the existence of a finely-tuned mechanism regulating directional apical:basal sorting and secretion of drusen-associated proteins via EVs, and its modulation in response to mechanisms involved in AMD pathophysiology. Collectively, our results strongly support an active role of RPE-derived EVs as a key source of drusen proteins and important contributors to drusen development and growth.
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Affiliation(s)
- Miguel Flores‐Bellver
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Jason Mighty
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
| | - Silvia Aparicio‐Domingo
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Kang V. Li
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Cui Shi
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
| | | | - Hannah Cobb
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Patrick McGrath
- Department of DermatologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - German Michelis
- Section of Protein Structure and FunctionNEINIHBethesdaMarylandUSA
| | - Patricia Lenhart
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
| | - Ganna Bilousova
- Department of DermatologyUniversity of Colorado School of MedicineAuroraColoradoUSA
- Charles C. Gates Center for Regenerative MedicineUniversity of Colorado School of MedicineAuroraColoradoUSA
- Linda Crnic Institute for Down SyndromeUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Søren Heissel
- Proteomics Resource CenterThe Rockefeller UniversityNew YorkNew YorkUSA
| | - Michael J. Rudy
- Department of NeurologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Christina Coughlan
- University of Colorado Alzheimer's and Cognition CenterDepartment of NeurologyLinda Crnic Institute for Down SyndromeUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Andrew E. Goodspeed
- Department of PharmacologyUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
- University of Colorado Cancer CenterUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | | | - Stephen Redenti
- Lehman CollegeBronxNew YorkUSA
- Biology Doctoral ProgramThe Graduate School and University CenterCity University of New YorkNew YorkNew YorkUSA
- Biochemistry Doctoral ProgramThe Graduate SchoolCity University of New YorkNew YorkNew YorkUSA
| | - M. Valeria Canto‐Soler
- CellSight Ocular Stem Cell and Regeneration ProgramDepartment of OphthalmologySue Anschutz‐Rodgers Eye CenterUniversity of Colorado, School of MedicineAuroraColoradoUSA
- Charles C. Gates Center for Regenerative MedicineUniversity of Colorado School of MedicineAuroraColoradoUSA
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