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Special Issue "Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0"

Special Issue Editors

Prof. Dr. Janusz Blasiak
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Guest Editor
Faculty of Biology and Environmental Sciences, Department of Molecular Genetics, University of Lodz, Lodz, Poland
Interests: DNA and RNA structure; DNA damage and repair; DNA damage response; mutagenesis; cancer transformation; age-related macular degeneration; autophagy; mitochondrial quality control; mitophagy; miRNA-lncRNA regulation; gene regulation; epigenetics
Special Issues and Collections in MDPI journals
Prof. Dr. Kai Kaarniranta
Website
Co-Guest Editor
Department of Ophthalmology, Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland
Interests: aging; autophagy; eye diseases; genetics; macula; oxidative stress; proteolysis; retinal pigment epithelium
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Age-related macular degeneration (AMD) is the main cause of blindness in the elderly in developed countries and is an emerging health and social problem, as the number of individuals affected by AMD in 2020 is estimated to reach about 200 million. Therefore, AMD is an important element of the global issue of vision loss. Additionally, there is no efficient treatment in most AMD cases. AMD is a complex disease that is associated with aging and several genetic and environmental risk factors. Cellular reaction to oxidative stress, senescence, autophagy, inflammatory response, and DNA damage reaction are frequently reported to be impaired in AMD, but causative relationships between AMD and these effects are not completely clear. Therefore, studies on the molecular mechanisms of AMD pathogenesis are justified and can bring results important regarding its biology and therapy.

This Special Issue welcomes both original papers and review articles addressing one or several of the abovementioned issues, or of the topics mentioned in the keywords listed below.

This Special Issue is the continuation of our previous Special Issue, “Molecular Biology of Age-Related Macular Degeneration (AMD)”.

Prof. Dr. Janusz Blasiak
Prof. Dr. Kai Kaarniranta
Guest Editors

Manuscript Submission Information

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Keywords

  • AMD pathogenesis
  • Retinal pigment epithelium, photoreceptors, and choriocapillaris in AMD
  • Oxidative stress and antioxidant system in AMD
  • Senescence and organismal aging in AMD
  • Mitochondrial quality control in AMD
  • Autophagy and mitophagy in AMD
  • DNA damage reaction in the nucleus and mitochondria in retinal pigment epithelium
  • DNA damage and repair in AMD
  • AMD genetics: mutations and polymorphisms of genes related to AMD
  • AMD epigenetics
  • Programmed cell death, including apoptosis, pyroptosis, and necroptosis in ertinal pigment epithelium
  • Inflammation and the inflammasome activation
  • miRNA-lncRNA regulation in AMD
  • Neurodegenerative diseases related to AMD
  • Models to study AMD pathogenesis

Related Special Issue

Published Papers (8 papers)

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Research

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Open AccessArticle
Effects of FTMT Expression by Retinal Pigment Epithelial Cells on Features of Angiogenesis
Int. J. Mol. Sci. 2020, 21(10), 3635; https://doi.org/10.3390/ijms21103635 - 21 May 2020
Abstract
Aberrant angiogenesis is a pathological feature of a number of diseases and arises from the uncoordinated expression of angiogenic factors as response to different cellular stresses. Age-related macular degeneration (AMD), a leading cause of vision loss, can result from pathological angiogenesis. As a [...] Read more.
Aberrant angiogenesis is a pathological feature of a number of diseases and arises from the uncoordinated expression of angiogenic factors as response to different cellular stresses. Age-related macular degeneration (AMD), a leading cause of vision loss, can result from pathological angiogenesis. As a mutation in the mitochondrial ferritin (FTMT) gene has been associated with AMD, its possible role in modulating angiogenic factors and angiogenesis was investigated. FTMT is an iron-sequestering protein primarily expressed in metabolically active cells and tissues with high oxygen demand, including retina. In this study, we utilized the human retinal pigment epithelial cell line ARPE-19, both as undifferentiated and differentiated cells. The effects of proinflammatory cytokines, FTMT knockdown, and transient and stable overexpression of FTMT were investigated on expression of pro-angiogenic vascular endothelial growth factor (VEGF) and anti-angiogenic pigment epithelial-derived factor (PEDF). Proinflammatory cytokines induced FTMT and VEGF expression, while NF-κB inhibition significantly reduced FTMT expression. VEGF protein and mRNA expression were significantly increased in FTMT-silenced ARPE-19 cells. Using an in vitro angiogenesis assay with endothelial cells, we showed that conditioned media from FTMT-overexpressing cells had significant antiangiogenic effects. Collectively, our findings indicate that increased levels of FTMT inhibit angiogenesis, possibly by reducing levels of VEGF and increasing PEDF expression. The cellular models developed can be used to investigate if increased FTMT may be protective in angiogenic diseases, such as AMD. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessArticle
Resvega Alleviates Hydroquinone-Induced Oxidative Stress in ARPE-19 Cells
Int. J. Mol. Sci. 2020, 21(6), 2066; https://doi.org/10.3390/ijms21062066 - 17 Mar 2020
Abstract
Retinal pigment epithelial (RPE) cells maintain homeostasis at the retina and they are under continuous oxidative stress. Cigarette smoke is a prominent environmental risk factor for age-related macular degeneration (AMD), which further increases the oxidant load in retinal tissues. In this study, we [...] Read more.
Retinal pigment epithelial (RPE) cells maintain homeostasis at the retina and they are under continuous oxidative stress. Cigarette smoke is a prominent environmental risk factor for age-related macular degeneration (AMD), which further increases the oxidant load in retinal tissues. In this study, we measured oxidative stress and inflammatory markers upon cigarette smoke-derived hydroquinone exposure on human ARPE-19 cells. In addition, we studied the effects of commercial Resvega product on hydroquinone-induced oxidative stress. Previously, it was observed that Resvega induces autophagy during impaired protein clearance in ARPE-19 cells, for which it has the potential to alleviate pro-inflammatory pathways. Cell viability was determined while using the lactate dehydrogenase (LDH) and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, and the cytokine levels were measured using the enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) production were measured using the 2′,7′-dichlorofluorescin diacetate (H2DCFDA) probe. Hydroquinone compromised the cell viability and increased ROS production in ARPE-19 cells. Resvega significantly improved cell viability upon hydroquinone exposure and reduced the release of interleukin (IL)-8 and monocytic chemoattractant protein (MCP)-1 from RPE cells. Resvega, N-acetyl-cysteine (NAC) and aminopyrrolidine-2,4-dicarboxylic acid (APDC) alleviated hydroquinone-induced ROS production in RPE cells. Collectively, our results indicate that hydroquinone induces cytotoxicity and increases oxidative stress through NADPH oxidase activity in RPE cells, and resveratrol-containing Resvega products prevent those adverse effects. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessArticle
Mitophagy in the Retinal Pigment Epithelium of Dry Age-Related Macular Degeneration Investigated in the NFE2L2/PGC-1α-/- Mouse Model
Int. J. Mol. Sci. 2020, 21(6), 1976; https://doi.org/10.3390/ijms21061976 - 13 Mar 2020
Cited by 1
Abstract
Increased oxidative stress and mitochondrial damage are observed in protein aggregation diseases, such as age-related macular degeneration (AMD). We have recently reported elevated levels of oxidative stress markers, damaged mitochondria, accumulating lysosomal lipofuscin and extracellular drusen-like structures in the retinal pigment epithelial cells [...] Read more.
Increased oxidative stress and mitochondrial damage are observed in protein aggregation diseases, such as age-related macular degeneration (AMD). We have recently reported elevated levels of oxidative stress markers, damaged mitochondria, accumulating lysosomal lipofuscin and extracellular drusen-like structures in the retinal pigment epithelial cells (RPE) of the dry AMD-resembling NFE2L2/PGC1α double knockout (dKO) mouse model. Here, we provide evidence of a disturbance in the autolysosomal machinery handling mitochondrial clearance in the RPE cells of one-year-old NFE2L2/PGC1α-deficient mice. Confocal immunohistochemical analysis revealed an upregulation of autophagosome marker microtubule-associated proteins 1A/1B light chain 3B (LC3B) as well as numerous mitophagy markers, such as PTE-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase (PARKIN) together with damaged mitochondria. However, we detected no evidence of increased autolysosome formation in transmission electron micrographs or of colocalization of lysosomal marker LAMP2 (lysosome-associated membrane protein 2) and the mitochondrial marker ATP synthase β in confocal micrographs. Interestingly, we observed an upregulation of late autolysosomal fusion Ras-related protein (Rab7) in the perinuclear space of RPE cells together with autofluorescence aggregates. Our results reveal that there is at least a relative decrease of mitophagy in the RPE cells of NFE2L2/PGC1α dKO mice. This further supports the hypothesis that mitophagy is a putative therapy target in AMD-like pathology. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessArticle
Resveratrol as Inducer of Autophagy, Pro-Survival, and Anti-Inflammatory Stimuli in Cultured Human RPE Cells
Int. J. Mol. Sci. 2020, 21(3), 813; https://doi.org/10.3390/ijms21030813 - 27 Jan 2020
Cited by 1
Abstract
Purpose: To investigate the mechanism by which resveratrol acts upon retinal pigment epithelial (RPE) cells and to characterize its effect upon autophagy, survival, and inflammation, with consequent implications to treatment for age-related macular degeneration (AMD). Methods: Cultured ARPE-19 cells were exposed to 10 [...] Read more.
Purpose: To investigate the mechanism by which resveratrol acts upon retinal pigment epithelial (RPE) cells and to characterize its effect upon autophagy, survival, and inflammation, with consequent implications to treatment for age-related macular degeneration (AMD). Methods: Cultured ARPE-19 cells were exposed to 10 and 50 μM resveratrol. Cell survival/death was determined by annexin-FITC/propidium iodide using flow cytometry, while autophagy was studied by detecting autophagic vacuoles formation (acridine orange and transmission electron microscopy), as well as LC3II/I ratio and p62 expression by Western blot. In addition, time-lapse confocal microscopy of a pDENDRA-LC3 expression vector was performed to detect autophagy in transfected ARPE-19 cells under the different treatment conditions. Inhibition of proteasomal and autophagy-lysosomal fusion was carried out by MG-132 and chloroquine, respectively, while induction of autophagy was achieved by rapamycin treatment. Detection of secreted cytokines by ARPE-19 cells using Human XL Cytokine Array was performed under oxidative stress (H2O2) and resveratrol treatments, respectively. Results: Resveratrol induced autophagy in ARPE-19 cells as determined by augmented presence of autophagic vacuoles, increased LC3II/I ratio and decreased p62 expression, as well as time-lapse confocal microscopy using pDENDRA-LC3 expression vector. Resveratrol acted similarly to proteasomal inhibition and downstream of mammalian target of rapamycin (mTOR), since upstream inhibition of autophagy by 3-methyladenine could not inhibit autophagy in ARPE-19 cells. Co-treatmeant by rapamycin and/or proteasome inhibition showed no additive effect upon autophagy induction. ARPE-19 cells treated by resveratrol showed lower cell death rate compared to untreated controls. Resveratrol induced a specific anti-inflammatory response in ARPE-19 cells. Conclusions: Resveratrol can induce autophagy, pro-survival, and anti-inflammatory stimuli in ARPE-19 cells, properties which could be plausible to formulate future treatment modalities for AMD. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessArticle
Lack of Delta-Sarcoglycan (Sgcd) Results in Retinal Degeneration
Int. J. Mol. Sci. 2019, 20(21), 5480; https://doi.org/10.3390/ijms20215480 - 04 Nov 2019
Abstract
Age-related macular degeneration (AMD) is the leading cause of central vision loss and severe blindness among the elderly population. Recently, we reported on the association of the SGCD gene (encoding for δ-sarcoglycan) polymorphisms with AMD. However, the functional consequence of Sgcd alterations in [...] Read more.
Age-related macular degeneration (AMD) is the leading cause of central vision loss and severe blindness among the elderly population. Recently, we reported on the association of the SGCD gene (encoding for δ-sarcoglycan) polymorphisms with AMD. However, the functional consequence of Sgcd alterations in retinal degeneration is not known. Herein, we characterized changes in the retina of the Sgcd knocked-out mouse (KO, Sgcd−/−). At baseline, we analyzed the retina structure of three-month-old wild-type (WT, Sgcd+/+) and Sgcd−/− mice by hematoxylin and eosin (H&E) staining, assessed the Sgcd–protein complex (α-, β-, γ-, and ε-sarcoglycan, and sarcospan) by immunofluorescence (IF) and Western blot (WB), and performed electroretinography. Compared to the WT, Sgcd−/− mice are five times more likely to have retinal ruptures. Additionally, all the retinal layers are significantly thinner, more so in the inner plexiform layer (IPL). In addition, the number of nuclei in the KO versus the WT is ever so slightly increased. WT mice express Sgcd-protein partners in specific retinal layers, and as expected, KO mice have decreased or no protein expression, with a significant increase in the α subunit. At three months of age, there were no significant differences in the scotopic electroretinographic responses, regarding both a- and b-waves. According to our data, Sgcd−/− has a phenotype that is compatible with retinal degeneration. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Review

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Open AccessReview
Experimental Models in Neovascular Age Related Macular Degeneration
Int. J. Mol. Sci. 2020, 21(13), 4627; https://doi.org/10.3390/ijms21134627 - 29 Jun 2020
Abstract
Neovascular age-related macular degeneration (vAMD), characterized by the neo-vascularization of the retro-foveolar choroid, leads to blindness within few years. This disease depends on angiogenesis mediated by the vascular endothelial growth factor A (VEGF) and to inflammation. The only available treatments consist of monthly [...] Read more.
Neovascular age-related macular degeneration (vAMD), characterized by the neo-vascularization of the retro-foveolar choroid, leads to blindness within few years. This disease depends on angiogenesis mediated by the vascular endothelial growth factor A (VEGF) and to inflammation. The only available treatments consist of monthly intravitreal injections of antibodies directed against VEGF or VEGF/VEGFB/PlGF decoy receptors. Despite their relative efficacy, these drugs only delay progression to blindness and 30% of the patients are insensitive to these treatments. Hence, new therapeutic strategies are urgently needed. Experimental models of vAMD are essential to screen different innovative therapeutics. The currently used in vitro and in vivo models in ophthalmic translational research and their relevance are discussed in this review. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessReview
EMT and EndMT: Emerging Roles in Age-Related Macular Degeneration
Int. J. Mol. Sci. 2020, 21(12), 4271; https://doi.org/10.3390/ijms21124271 - 16 Jun 2020
Abstract
Epithelial–mesenchymal transition (EMT) and endothelial–mesenchymal transition (EndMT) are physiological processes required for normal embryogenesis. However, these processes can be hijacked in pathological conditions to facilitate tissue fibrosis and cancer metastasis. In the eye, EMT and EndMT play key roles in the pathogenesis of [...] Read more.
Epithelial–mesenchymal transition (EMT) and endothelial–mesenchymal transition (EndMT) are physiological processes required for normal embryogenesis. However, these processes can be hijacked in pathological conditions to facilitate tissue fibrosis and cancer metastasis. In the eye, EMT and EndMT play key roles in the pathogenesis of subretinal fibrosis, the end-stage of age-related macular degeneration (AMD) that leads to profound and permanent vision loss. Predominant in subretinal fibrotic lesions are matrix-producing mesenchymal cells believed to originate from the retinal pigment epithelium (RPE) and/or choroidal endothelial cells (CECs) through EMT and EndMT, respectively. Recent evidence suggests that EMT of RPE may also be implicated during the early stages of AMD. Transforming growth factor-beta (TGFβ) is a key cytokine orchestrating both EMT and EndMT. Investigations in the molecular mechanisms underpinning EMT and EndMT in AMD have implicated a myriad of contributing factors including signaling pathways, extracellular matrix remodelling, oxidative stress, inflammation, autophagy, metabolism and mitochondrial dysfunction. Questions arise as to differences in the mesenchymal cells derived from these two processes and their distinct mechanistic contributions to the pathogenesis of AMD. Detailed discussion on the AMD microenvironment highlights the synergistic interactions between RPE and CECs that may augment the EMT and EndMT processes in vivo. Understanding the differential regulatory networks of EMT and EndMT and their contributions to both the dry and wet forms of AMD can aid the development of therapeutic strategies targeting both RPE and CECs to potentially reverse the aberrant cellular transdifferentiation processes, regenerate the retina and thus restore vision. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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Open AccessReview
Circadian Rhythms in Exudative Age-Related Macular Degeneration: The Key Role of the Canonical WNT/β-Catenin Pathway
Int. J. Mol. Sci. 2020, 21(3), 820; https://doi.org/10.3390/ijms21030820 - 27 Jan 2020
Cited by 1
Abstract
Age-related macular degeneration (AMD) is considered as the main worldwide cause of blindness in elderly adults. Exudative AMD type represents 10 to 15% of macular degeneration cases, but is the main cause of vision loss and blindness. Circadian rhythm changes are associated with [...] Read more.
Age-related macular degeneration (AMD) is considered as the main worldwide cause of blindness in elderly adults. Exudative AMD type represents 10 to 15% of macular degeneration cases, but is the main cause of vision loss and blindness. Circadian rhythm changes are associated with aging and could further accelerate it. However, the link between circadian rhythms and exudative AMD is not fully understood. Some evidence suggests that dysregulation of circadian functions could be manifestations of diseases or could be risk factors for the development of disease in elderly adults. Biological rhythms are complex systems interacting with the environment and control several physiological pathways. Recent findings have shown that the dysregulation of circadian rhythms is correlated with exudative AMD. One of the main pathways involved in exudative AMD is the canonical WNT/β-catenin pathway. Circadian clocks have a main role in some tissues by driving the circadian expression of genes involved in physiological and metabolic functions. In exudative AMD, the increase of the canonical WNT/β-catenin pathway is enhanced by the dysregulation of circadian rhythms. Exudative AMD progression is associated with major metabolic reprogramming, initiated by aberrant WNT/β-catenin pathway, of aerobic glycolysis. This review focuses on the interest of circadian rhythm dysregulation in exudative AMD through the aberrant upregulation of the canonical WNT/β-catenin pathway. Full article
(This article belongs to the Special Issue Molecular Biology of Age-Related Macular Degeneration (AMD) 2.0)
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