7-ketocholesterol induces endothelial-mesenchymal transition and promotes fibrosis: implications in neovascular age-related macular degeneration and treatment

Angiogenesis ◽  
2021 ◽  
Author(s):  
Haibo Wang ◽  
Aniket Ramshekar ◽  
Eric Kunz ◽  
M. Elizabeth Hartnett
2020 ◽  
Vol 21 (12) ◽  
pp. 4271 ◽  
Author(s):  
Daisy Y. Shu ◽  
Erik Butcher ◽  
Magali Saint-Geniez

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.


Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1617 ◽  
Author(s):  
Annamaria Tisi ◽  
Vincenzo Flati ◽  
Simona Delle Monache ◽  
Luca Lozzi ◽  
Maurizio Passacantando ◽  
...  

Retinal pigment epithelium (RPE) dysfunction and degeneration underlie the development of age-related macular degeneration (AMD), which is the leading cause of blindness worldwide. In this study, we investigated whether cerium oxide nanoparticles (CeO2-NPs or nanoceria), which are anti-oxidant agents with auto-regenerative properties, are able to preserve the RPE. On ARPE-19 cells, we found that CeO2-NPs promoted cell viability against H2O2–induced cellular damage. For the in vivo studies, we used a rat model of acute light damage (LD), which mimics many features of AMD. CeO2-NPs intravitreally injected three days before LD prevented RPE cell death and degeneration and nanoceria labelled with fluorescein were found localized in the cytoplasm of RPE cells. CeO2-NPs inhibited epithelial-mesenchymal transition of RPE cells and modulated autophagy by the down-regulation of LC3B-II and p62. Moreover, the treatment inhibited nuclear localization of LC3B. Taken together, our study demonstrates that CeO2-NPs represent an eligible candidate to counteract RPE degeneration and, therefore, a powerful therapy for AMD.


2019 ◽  
Vol 20 (22) ◽  
pp. 5800 ◽  
Author(s):  
Hyttinen ◽  
Kannan ◽  
Felszeghy ◽  
Niittykoski ◽  
Salminen ◽  
...  

Age-related macular degeneration (AMD) is a mounting cause of loss of sight in the elderly in the developed countries, a trend enhanced by the continual ageing of the population. AMD is a multifactorial and only partly understood, malady. Unfortunately, there is no effective treatment for most AMD patients. It is known that oxidative stress (OS) damages the retinal pigment epithelium (RPE) and contributes to the progression of AMD. We review here the potential importance of two OS-related cellular systems in relation to AMD. First, the nuclear factor erythroid 2-related factor 2 (NFE2L2; NRF2)-mediated OS response signalling pathway is important in the prevention of oxidative damage and a failure of this system could be critical in the development of AMD. Second, epithelial-to-mesenchymal transition (EMT) represents a change in the cellular phenotype, which ultimately leads to the fibrosis encountered in RPE, a characteristic of AMD. Many of the pathways triggering EMT are promoted by OS. The possible interconnections between these two signalling routes are discussed here. From a broader perspective, the control of NFE2L2 and EMT as ways of preventing OS-derived cellular damage could be potentially valuable in the therapy of AMD.


2001 ◽  
Vol 58 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Ursula Körner-Stiefbold

Die altersbedingte Makuladegeneration (AMD) ist eine der häufigsten Ursachen für einen irreversiblen Visusverlust bei Patienten über 65 Jahre. Nahezu 30% der über 75-Jährigen sind von einer AMD betroffen. Trotz neuer Erkenntnisse in der Grundlagenforschung ist die Ätiologie, zu der auch genetische Faktoren gehören, noch nicht völlig geklärt. Aus diesem Grund sind die Behandlungsmöglichkeiten zum jetzigen Zeitpunkt noch limitiert, so dass man lediglich von Therapieansätzen sprechen kann. Die derzeit zur Verfügung stehenden Möglichkeiten wie medikamentöse, chirurgische und laser- und strahlentherapeutische Maßnahmen werden beschrieben.


2018 ◽  
Author(s):  
Rebekah Stevens ◽  
Richard Cooke ◽  
Hannah Bartlett

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