scholarly journals Systems Biology Profiling of AMD on the Basis of Gene Expression

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mones S. Abu-Asab ◽  
Jose Salazar ◽  
Jingsheng Tuo ◽  
Chi-Chao Chan
Keyword(s):  
Gene Expression ◽  
Systems Biology ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Disease Spectrum ◽  
Age Related ◽  
Dry Amd ◽  
Pathway Networks

Genetic pathways underlying the initiation and progression of age-related macular degeneration (AMD) have not been yet sufficiently revealed, and the correlations of AMD’s genotypes, phenotypes, and disease spectrum are still awaiting resolution. We are tackling both problems with systems biology phylogenetic parsimony analysis. Gene expression data (GSE29801: NCBI, Geo) of macular and extramacular specimens of the retinas and retinal pigment epithelium (RPE) choroid complexes representing dry AMD without geographic atrophy (GA), choroidal neovascularization (CNV), GA, as well as pre-AMD and subclinical pre-AMD were polarized against their respective normal specimens and then processed through the parsimony program MIX to produce phylogenetic cladograms. Gene lists from cladograms’ nodes were processed in Genomatix GePS to reveal the affected signaling pathway networks. Cladograms exposed a highly heterogeneous transcriptomic profiles within all the conventional phenotypes. Moreover, clades and nodal synapomorphies did not support the classical AMD phenotypes as valid transcriptomal genotypes. Gene lists defined by cladogram nodes showed that the AMD-related deregulations occurring in the neural retina were different from those in RPE-choroidal tissue. Our analysis suggests a more complex transcriptional profile of the phenotypes than expected. Evaluation of the disease in much earlier stages is needed to elucidate the initial events of AMD.

Age-related macular degeneration treatment: current view (literature review)

2014 ◽  
Vol 21 (1) ◽  
pp. 43-50
Author(s):  
Monika Kalesinskaitė ◽  
Diana Uljanionok ◽  
Rasa Liutkevičienė
Keyword(s):  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Treatment Options ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Current View ◽  
Neovascular Amd ◽  
Age Related ◽  
Dry Amd

Age-related macular degeneration (AMD) – is a damage of the macula, accompanied by a significant and irreversible loss of central vision. It is a major cause of blindness and visual impairment in older adults (>60 years). Damage of the retina always includes both eyes, though the intensity can vary. Early AMD is defined as the presence of drusen and retinal pigmentary abnormalities (RPE); late AMD includes dry AMD (geographic atrophy of the RPE in the absence of neovascular AMD) or neovascular AMD  (detachment of the retinal pigment epithelium, hemorrhages, and/or scars). Unfortunately, the etiology and pathogenesis of AMD aren’t fully understood up to now, so treatment options are limited and not always effective. This article briefly reviews the options of initial and late forms of AMD treatment

Origins of Ghost Drusen: A follow-up Analysis

2017 ◽  
Vol 1 (1) ◽  
pp. oapoc.0000011
Author(s):  
Caroline Bottin ◽  
Olivia Zambrowski ◽  
Giuseppe Querques ◽  
Salomon Yves Cohen ◽  
Mayer Srour ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Geographic Atrophy ◽  
Primary Lesion ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Soft Drusen ◽  
Initial Lesions ◽  
Sd Oct

Purpose Ghost drusen (GD) are pyramidal or dome-shaped retinal pigment epithelium elevations observed in some geographic atrophy (GA) areas in the context of age-related macular degeneration (AMD). The purpose was to investigate the first morphologic features preceding GD on spectral-domain optical coherence tomography (SD-OCT) on patients with GA associated with AMD. Methods A retrospective observational study was performed on a series of patients with GA that had at least 3 years of follow-up. Using the follow-up tool of SD-OCT, we tracked the initial lesions that could lead to GD. Results Among 442 patients with GA, 37 had well defined GD (8%). We included the 17/37 patients (31 eyes) with at least 3 years of follow-up for analysis, which led to a total of 582 counted GD. Most GD were already present at the first visit, and remained stable. However, on 13 of the 582 analyzed GD (2.2%), soft drusen were shown as the initial lesion, which progressively turned into GD. Conclusions GD were observed in less than 10% of eyes with GA. None of the ghost drusen turned into another shaped lesion, suggesting that GD is a possible final stage of evolution. In a few cases, large drusen were shown as the primary lesion that progressed into GD.

scholarly journals Embryonic stem cell microenvironment enhances proliferation of human retinal pigment epithelium cells by activating the PI3K signaling pathway

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiahui Liu ◽  
Liu Yang ◽  
Xiaoran Wang ◽  
Shoubi Wang ◽  
Zheqian Huang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cell ◽  
Signaling Pathway ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Embryonic Stem ◽  
Age Related Macular Degeneration ◽  
Pi3k Signaling ◽  
Age Related ◽  
Pi3k Signaling Pathway

Abstract Background Retinal pigment epithelium (RPE) replacement has been proposed as an efficacious treatment for age-related macular degeneration (AMD), which is the primary cause of vision loss in the elderly worldwide. The embryonic stem cell (ESC) microenvironment has been demonstrated to enable mature cells to gain a powerful proliferative ability and even enhance the stem/progenitor phenotype via activation of the phosphoinositide 3-kinase (PI3K) signaling pathway. As the PI3K signaling pathway plays a pivotal role in proliferation and homeostasis of RPE, we hypothesize that the stemness and proliferative capability of RPE can be enhanced by the ESC microenvironment via activation of the PI3K signaling pathway. Methods To investigate whether the ESC microenvironment improves the stem cell phenotype and proliferation properties of human RPE (hRPE) cells by regulating the PI3K signaling pathway, primary hRPE cells were cocultured with either ESCs or human corneal epithelial cells (CECs) for 72 h, after which their proliferation, apoptosis, cell cycle progression, and colony formation were assayed to evaluate changes in their biological characteristics. Gene expression was detected by real-time PCR and protein levels were determined by western blotting or immunofluorescence. LY294002, an antagonist of the PI3K signaling pathway, was used to further confirm the mechanism involved. Results In comparison to hRPE cells cultured alone, hRPE cells cocultured with ESCs had an increased proliferative capacity, reduced apoptotic rate, and higher colony-forming efficiency. The expression of the stem cell-associated marker KLF4 and the differentiation marker CRALBP increased and decreased, respectively, in hRPE cells isolated from the ESC coculture. Furthermore, PI3K pathway-related genes were significantly upregulated in hRPE cells after exposure to ESCs. LY294002 reversed the pro-proliferative effect of ESCs on hRPE cells. In contrast, CECs did not share the ability of ESCs to influence the biological behavior and gene expression of hRPE cells. Conclusions Our findings indicate that the ESC microenvironment enhances stemness and proliferation of hRPE cells, partially via activation of the PI3K signaling pathway. This study may have a significant impact and clinical implication on cell therapy in regenerative medicine, specifically for age-related macular degeneration.

scholarly journals CIB2 regulates autophagy via Rheb-mTORC1 signaling axis

2020 ◽  
Author(s):  
Saumil Sethna ◽  
Steven L. Bernstein ◽  
Xiaoying Jian ◽  
Sheikh Riazuddin ◽  
Paul A. Randazzo ◽  
...  
Keyword(s):  
Vision Loss ◽  
Neurodegenerative Disorder ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Negative Regulator ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Mtorc1 Signaling ◽  
Signaling Axis ◽  
Dry Amd

SUMMARYAge-related macular degeneration (AMD), a multifactorial neurodegenerative disorder, is the most common cause of vision loss in the elderly. Deficits in autophagy have been associated with age-related retinal pigment epithelium (RPE) pathology in mice, and dry-AMD in humans. In this study, we establish that the calcium and integrin binding protein 2 (CIB2) regulates autophagy in the RPE via Rheb-mTORC1 signaling axis. Cib2 mutant mice have reduced autophagic clearance in RPE and increased mTORC1 signaling – a negative regulator of autophagy. Concordant molecular deficits were also observed in RPE/choroid tissues from humans affected with dry AMD. Mechanistically, CIB2 negatively regulates mTORC1 by preferentially binding to ‘nucleotide empty’ or inactive GDP-loaded Rheb. Upregulated mTORC1 signaling has been implicated in aging, Tuberous sclerosis complex (TSC), and lymphangioleiomyomatosis (LAM) cancer. Over-expressing CIB2 in LAM patient-derived fibroblasts and Tsc2 null cell line down-regulates hyperactive mTORC1 signaling. Thus, our findings have significant ramifications for the etiology of AMD and mTORC1 hyperactivity disorders and treatments.

scholarly journals Human iPSC-derived retinal pigment epithelium: a model system for identifying and functionally characterizing causal variants at AMD risk loci

2018 ◽  
Author(s):  
Erin N. Smith ◽  
Agnieszka D’Antonio-Chronowska ◽  
William W. Greenwald ◽  
Victor Borja ◽  
Lana R. Aguiar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Induced Pluripotent Stem Cell ◽  
Age Related Macular Degeneration ◽  
Molecular Characteristics ◽  
Specific Expression ◽  
Age Related ◽  
Causal Variants

SummaryWe evaluate whether human induced pluripotent stem cell-derived retinal pigment epithelium (iPSC-RPE) cells can be used to prioritize and functionally characterize causal variants at age-related macular degeneration (AMD) risk loci. We generated iPSC-RPE from six subjects and show that they have morphological and molecular characteristics similar to native RPE. We generated RNA-seq, ATAC-seq, and H3K27ac ChIP-seq data and observe high similarity in gene expression and enriched transcription factor motif profiles between iPSC-RPE and human fetal-RPE. We performed fine-mapping of AMD risk loci by integrating molecular data from the iPSC-RPE, adult retina, and adult RPE, which identified rs943080 as the probable causal variant at VEGFA. We show that rs943080 is associated with altered chromatin accessibility of a distal ATAC-seq peak, decreased overall gene expression of VEGFA, and allele specific expression of a non-coding transcript. These results provide insight into the mechanism underlying the association of the VEGFA locus with AMD.

Clinical and Functional Characteristics of Secondary Geographic Atrophy Against the Background of Exudative Age-Related Macular Degeneration

2021 ◽  
Vol 76 (4) ◽  
pp. 384-393
Author(s):  
Vladimir V. Neroev ◽  
Marina V. Zueva ◽  
Natalia V. Neroeva ◽  
Ludmila A. Katargina ◽  
Oksana A. Losanova ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Antiangiogenic Therapy ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Flicker Erg ◽  
Wet Amd

Background.Studies demonstrate the need for long-term follow-up of patients with wet age-related macular degeneration (AMD) treated with inhibitors of angiogenesis to monitor long-term vision outcomes and assess the safety of antiangiogenic therapy in relation to the risk of secondary geographic atrophy. Aims to determine the characteristic clinical and functional signs of secondary GA that developed against the background of wet AMD. Methods.In 22 patients (25 eyes) with wet AMD and 18 healthy subjects comparable in age and sex standard ophthalmological and instrumental studies were performed and photopic electroretinograms (ERGs) were recorded according to ISCEV standards, flicker-ERGs, multifocal ERGs and electrooculogram. Results.The appearance of the area of secondary atrophy against the background of wet AMD in eyes treated with inhibitors of angiogenesis is clinically indistinguishable from areas of geographic atrophy that developed as an outcome of dry AMD. The ERG-signs of secondary atrophy are described, which are similar to the biomarkers of primary atrophy and specifically differ from them. Secondary atrophy is characterized by the dependence of the increase in the b/a ratio on the atrophic area, reducing of the 8.3 Hz-flicker-ERG amplitude in the absence of 24 Hz-flicker ERG changes. In eyes with secondary atrophy, a significant decrease in the density of the multifocal ERG P1-peak was shown not only in the first hexagon but also in the parafoveal zone. The electrooculography results showed a sharper dark troughs decrease in with an increase in Ardens ratio in patients with secondary atrophya on the background of wet AMD, in contrast to the previously described changes in primary geographic atrophy. Conclusion.Comparison of the change in the b/a ratio with secondary atrophy area in patients with wet AMD may have clinical implications for assessing retinal dysfunction and predicting visual function. Secondary atrophy is associated with a pronounced inhibition of photoreceptor activity with better preservation of cone bipolar cells. The ERG and electrooculography data taking together indicate a more significant dysfunction of the retinal pigment epithelium in GA against the background of wet AMD and the associated deterioration of photoreceptor function than the changes characterizing primary geographic atrophy.

scholarly journals Choriocapillaris Loss in Advanced Age-Related Macular Degeneration

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Carlos A. Moreira-Neto ◽  
Eric M. Moult ◽  
James G. Fujimoto ◽  
Nadia K. Waheed ◽  
Daniela Ferrara
Keyword(s):  
Macular Degeneration ◽  
Current Knowledge ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Advanced Age ◽  
Tissue Loss ◽  
Age Related

The purpose of this review is to summarize the current knowledge on choriocapillaris loss in advanced age macular degeneration (AMD). Several histopathological studies in animal models and human eyes had showed that the choriocapillaris density decreases with age. However, the role of choriocapillaris loss is still unclear in AMD and its advanced forms, either choroidal neovascularization (CNV) or geographic atrophy (GA). Some authors have hypothesized that choriocapillaris loss might precede overt retinal pigment epithelium atrophy. Others have hypothesized that deposition of complement complexes on and around the choriocapillaris could be related to the tissue loss observed in early AMD. The development of imaging modalities, such as optical coherence tomography angiography (OCTA), have led to a better understanding of underlying physiopathological mechanisms in AMD. OCTA showed atrophy of choriocapillaris underneath and beyond the region of photoreceptors and RPE loss, in agreement with previous histopathologic studies. The evolution of OCTA technology suggests that CNV seems to originate from regions of severe choriocapillaris alteration. Significant progress has been made in the understanding of development and progression of GA and CNV. In vivo investigation of the choriocapillaris using OCTA may lead to new insights related to underlying disease mechanisms in AMD.

scholarly journals Complement System and Potential Therapeutics in Age-Related Macular Degeneration

2021 ◽  
Vol 22 (13) ◽  
pp. 6851
Author(s):  
Young-Gun Park ◽  
Yong-Soo Park ◽  
In-Beom Kim
Keyword(s):  
Macular Degeneration ◽  
Complement System ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelium Cell ◽  
Immune Surveillance ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
The Complement System

Age-related macular degeneration (AMD) is a complex multifactorial disease characterized in its late form by neovascularization (wet type) or geographic atrophy of the retinal pigment epithelium cell layer (dry type). The complement system is an intrinsic component of innate immunity. There has been growing evidence that the complement system plays an integral role in maintaining immune surveillance and homeostasis in AMD. Based on the association between the genotypes of complement variants and AMD occurrence and the presence of complement in drusen from AMD patients, the complement system has become a therapeutic target for AMD. However, the mechanism of complement disease propagation in AMD has not been fully understood. This concise review focuses on an overall understanding of the role of the complement system in AMD and its ongoing clinical trials. It provides further insights into a strategy for the treatment of AMD targeting the complement system.

scholarly journals NLRP3 Inflammasome: Activation and Regulation in Age-Related Macular Degeneration

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Jiangyuan Gao ◽  
Ruozhou Tom Liu ◽  
Sijia Cao ◽  
Jing Z. Cui ◽  
Aikun Wang ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
The Elderly ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Inflammasome Activation ◽  
Related Factors ◽  
Rpe Cells ◽  
Age Related

Age-related macular degeneration (AMD) is the leading cause of legal blindness in the elderly in industrialized countries. AMD is a multifactorial disease influenced by both genetic and environmental risk factors. Progression of AMD is characterized by an increase in the number and size of drusen, extracellular deposits, which accumulate between the retinal pigment epithelium (RPE) and Bruch’s membrane (BM) in outer retina. The major pathways associated with its pathogenesis include oxidative stress and inflammation in the early stages of AMD. Little is known about the interactions among these mechanisms that drive the transition from early to late stages of AMD, such as geographic atrophy (GA) or choroidal neovascularization (CNV). As part of the innate immune system, inflammasome activation has been identified in RPE cells and proposed to be a causal factor for RPE dysfunction and degeneration. Here, we will first review the classic model of inflammasome activation, then discuss the potentials of AMD-related factors to activate the inflammasome in both nonocular immune cells and RPE cells, and finally introduce several novel mechanisms for regulating the inflammasome activity.

scholarly journals Saponin-Mediated Rejuvenation of Bruch’s Membrane: A New Strategy for Intervention in Dry Age-Related Macular Degeneration (AMD)

2021 ◽  
Author(s):  
Yunhee Lee ◽  
Eun Jung Ahn ◽  
Ali Hussain
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Bruch's Membrane ◽  
Bruch’S Membrane ◽  
Age Related ◽  
New Strategy ◽  
The Matrix ◽  
Dry Amd ◽  
Underlying Mechanisms

At present, there is no treatment modality for the vast majority of patients with dry AMD. The pathophysiology of AMD is complex but current evidence suggests that abnormal ageing of Bruch’s membrane imparts a metabolic insult to the retinal pigment epithelium (RPE) and photoreceptor cells that leads eventually to the inflammatory-mediated death of these cells. Underlying mechanisms contributing to the pathology of Bruch’s membrane include the accumulation of ‘debris’ and malfunction of the matrix metalloproteinase (MMP) system resulting in diminished metabolic support of the retina and inefficient removal of toxic pro-inflammatory mediators. Saponins are amphipathic molecules that have a hydrophobic tri-terpenoid lipid region and hydrophilic glycosidic chains that allow for the dispersion of these deposits in Bruch’s and re-activation of the MMP system leading to a 2-fold improvement in the transport properties of the membrane. Such an intervention is expected to improve the bi-directional exchange of nutrients and waste products, thereby slowing the progression of dry AMD. This will be the first drug-based interventionist possibility to address dry AMD.

Sign in / Sign up

Export Citation Format

Share Document