scholarly journals A Zebrafish Model for Ocular Tuberculosis

2017 ◽  
Author(s):  
Kevin Takaki ◽  
Lalita Ramakrishnan ◽  
Soumyava Basu
Keyword(s):  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Tuberculous Infection ◽  
Blood Monocytes ◽  
Blood Retinal Barrier ◽  
Zebrafish Model ◽  
Ocular Tuberculosis ◽  
Department Of Health ◽  
Ocular Tb

AbstractOcular tuberculosis (TB) commonly causes severe inflammation and vision loss in TB-endemic countries. The mechanism by which tuberculous infection becomes established in the eye is poorly understood. We used Mycobacterium marinum-infected zebrafish larvae to study the early pathogenesis of ocular TB and found hematogenous bacterial seeding of the eye despite a functional blood retinal barrier. Prototypical early granulomas formed that involved the retinal vasculature and retinal pigment epithelium-choroid complex; characteristic locations for human ocular TB. Peripheral blood monocytes were recruited to the growing granuloma suggesting that the immune privileged nature of the eye is breached by this inflammatory focus.Conflict of interestnone disclosedFundingThis work was supported in part by a ‘Short-term fellowship’ to SB by Department of Health Research, Government of India.

scholarly journals Progressive Photoreceptor Dysfunction and Age-Related Macular Degeneration-Like Features in rp1l1 Mutant Zebrafish

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2214
Author(s):  
Nicole C. L. Noel ◽  
Nathan J. Nadolski ◽  
Jennifer C. Hocking ◽  
Ian M. MacDonald ◽  
W. Ted Allison
Keyword(s):  
Macular Degeneration ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Macular Dystrophy ◽  
Zebrafish Model ◽  
Photoreceptor Layer ◽  
Age Related ◽  
Subretinal Drusenoid Deposits

Photoreceptor disease results in irreparable vision loss and blindness, which has a dramatic impact on quality of life. Pathogenic mutations in RP1L1 lead to photoreceptor degenerations such as occult macular dystrophy and retinitis pigmentosa. RP1L1 is a component of the photoreceptor axoneme, the backbone structure of the photoreceptor’s light-sensing outer segment. We generated an rp1l1 zebrafish mutant using CRISPR/Cas9 genome editing. Mutant animals had progressive photoreceptor functional defects as determined by electrophysiological assessment. Optical coherence tomography showed gaps in the photoreceptor layer, disrupted photoreceptor mosaics, and thinner retinas. Mutant retinas had disorganized photoreceptor outer segments and lipid-rich subretinal drusenoid deposits between the photoreceptors and retinal pigment epithelium. Our mutant is a novel model of RP1L1-associated photoreceptor disease and the first zebrafish model of photoreceptor degeneration with reported subretinal drusenoid deposits, a feature of age-related macular degeneration.

scholarly journals Role of amyloid β-peptide in the pathogenesis of age-related macular degeneration

2021 ◽  
Vol 6 (1) ◽  
pp. e000774
Author(s):  
Minwei Wang ◽  
Shiqi Su ◽  
Shaoyun Jiang ◽  
Xinghuai Sun ◽  
Jiantao Wang
Keyword(s):  
Mitochondrial Dysfunction ◽  
Macular Degeneration ◽  
Vision Loss ◽  
Cell Structure ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Amyloid Β ◽  
Age Related Macular Degeneration ◽  
Amyloid Β Peptide ◽  
Age Related

Age-related macular degeneration (AMD) is the most common eye disease in elderly patients, which could lead to irreversible vision loss and blindness. Increasing evidence indicates that amyloid β-peptide (Aβ) might be associated with the pathogenesis of AMD. In this review, we would like to summarise the current findings in this field. The literature search was done from 1995 to Feb, 2021 with following keywords, ‘Amyloid β-peptide and age-related macular degeneration’, ‘Inflammation and age-related macular degeneration’, ‘Angiogenesis and age-related macular degeneration’, ‘Actin cytoskeleton and amyloid β-peptide’, ‘Mitochondrial dysfunction and amyloid β-peptide’, ‘Ribosomal dysregulation and amyloid β-peptide’ using search engines Pubmed, Google Scholar and Web of Science. Aβ congregates in subretinal drusen of patients with AMD and participates in the pathogenesis of AMD through enhancing inflammatory activity, inducing mitochondrial dysfunction, altering ribosomal function, regulating the lysosomal pathway, affecting RNA splicing, modulating angiogenesis and modifying cell structure in AMD. The methods targeting Aβ are shown to inhibit inflammatory signalling pathway and restore the function of retinal pigment epithelium cells and photoreceptor cells in the subretinal region. Targeting Aβ may provide a novel therapeutic strategy for AMD.

scholarly journals A human model of Batten disease shows role of CLN3 in phagocytosis at the photoreceptor–RPE interface

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Cynthia Tang ◽  
Jimin Han ◽  
Sonal Dalvi ◽  
Kannan Manian ◽  
Lauren Winschel ◽  
...  
Keyword(s):  
Photoreceptor Cell ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Loss ◽  
Human Model ◽  
Lysosomal Storage ◽  
Rpe Cells ◽  
Cln3 Disease

AbstractMutations in CLN3 lead to photoreceptor cell loss in CLN3 disease, a lysosomal storage disorder characterized by childhood-onset vision loss, neurological impairment, and premature death. However, how CLN3 mutations cause photoreceptor cell death is not known. Here, we show that CLN3 is required for phagocytosis of photoreceptor outer segment (POS) by retinal pigment epithelium (RPE) cells, a cellular process essential for photoreceptor survival. Specifically, a proportion of CLN3 in human, mouse, and iPSC-RPE cells localized to RPE microvilli, the site of POS phagocytosis. Furthermore, patient-derived CLN3 disease iPSC-RPE cells showed decreased RPE microvilli density and reduced POS binding and ingestion. Notably, POS phagocytosis defect in CLN3 disease iPSC-RPE cells could be rescued by wild-type CLN3 gene supplementation. Altogether, these results illustrate a novel role of CLN3 in regulating POS phagocytosis and suggest a contribution of primary RPE dysfunction for photoreceptor cell loss in CLN3 disease that can be targeted by gene therapy.

scholarly journals The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Annamaria Tisi ◽  
Marco Feligioni ◽  
Maurizio Passacantando ◽  
Marco Ciancaglini ◽  
Rita Maccarone
Keyword(s):  
Oxidative Stress ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Blood Retinal Barrier ◽  
Functional Changes ◽  
Beneficial Effects ◽  
Age Related ◽  
The Impact

The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch’s membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.

scholarly journals Disruption of the blood-retinal barrier at the retinal pigment epithelium in hypertension

1992 ◽  
Vol 33 (4) ◽  
pp. 562-562
Author(s):  
Sigeki Takahasi ◽  
Izuru Asaoka ◽  
Hirosi Takamura ◽  
Takeo Satoh
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Blood Retinal Barrier

scholarly journals PGC-1α Protects RPE Cells of the Aging Retina against Oxidative Stress-Induced Degeneration through the Regulation of Senescence and Mitochondrial Quality Control. The Significance for AMD Pathogenesis

2018 ◽  
Vol 19 (8) ◽  
pp. 2317 ◽  
Author(s):  
Kai Kaarniranta ◽  
Jakub Kajdanek ◽  
Jan Morawiec ◽  
Elzbieta Pawlowska ◽  
Janusz Blasiak
Keyword(s):  
Oxidative Stress ◽  
Cellular Senescence ◽  
Mitochondrial Biogenesis ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Sirtuin 1 ◽  
Age Related Macular Degeneration ◽  
Rpe Cells ◽  
Age Related

PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) is a transcriptional coactivator of many genes involved in energy management and mitochondrial biogenesis. PGC-1α expression is associated with cellular senescence, organismal aging, and many age-related diseases, including AMD (age-related macular degeneration), an important global issue concerning vision loss. We and others have developed a model of AMD pathogenesis, in which stress-induced senescence of retinal pigment epithelium (RPE) cells leads to AMD-related pathological changes. PGC-1α can decrease oxidative stress, a key factor of AMD pathogenesis related to senescence, through upregulation of antioxidant enzymes and DNA damage response. PGC-1α is an important regulator of VEGF (vascular endothelial growth factor), which is targeted in the therapy of wet AMD, the most devastating form of AMD. Dysfunction of mitochondria induces cellular senescence associated with AMD pathogenesis. PGC-1α can improve mitochondrial biogenesis and negatively regulate senescence, although this function of PGC-1α in AMD needs further studies. Post-translational modifications of PGC-1α by AMPK (AMP kinase) and SIRT1 (sirtuin 1) are crucial for its activation and important in AMD pathogenesis.

The Effects of Indocyanine Green Dye-Enhanced Photocoagulation on the Blood Flow in the Choriocapillaris and the Choroidal Neovascularization (CNV)

2000 ◽  
Author(s):  
C. von Kerczek ◽  
L. Zhu ◽  
A. Ernest ◽  
C. Eggleton ◽  
L. D. T. Topoleski ◽  
...  
Keyword(s):  
Laser Treatment ◽  
Choroidal Neovascularization ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
The United States ◽  
Age Related Macular Degeneration ◽  
Central Vision ◽  
Age Related ◽  
Direct Laser

Abstract Age-related macular degeneration (AMD) is the most common cause of vision loss in patients aged 65 years and older in the United States. In the majority of cases, the loss of central vision is secondary to exudative changes and fibrovascular scarring following choroidal neovascularization (CNV). Prompt laser treatment is recommended [Asrani et al., 1996; Macular Photocoagulation Study Group, 1993; Schneider et al, 1998]. However, direct laser treatment to the entire subfoveal lesion is almost invariably associated with immediate loss of central vision. Loss of central vision may be due to direct damage to foveal photoreceptors and retinal pigment epithelium or from damage to the nerve fiber layer serving foveal function [Han et al., 1988].

scholarly journals C-reactive protein isoforms differentially affect outer blood-retinal barrier integrity and function

2017 ◽  
Vol 312 (3) ◽  
pp. C244-C253 ◽  
Author(s):  
Blanca Molins ◽  
Anna Pascual ◽  
Méndez ◽  
Victor Llorenç ◽  
Javier Zarranz-Ventura ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Protein Isoforms ◽  
Age Related Macular Degeneration ◽  
C Reactive Protein ◽  
Barrier Dysfunction ◽  
Blood Retinal Barrier ◽  
Reactive Protein ◽  
Anti Vegf ◽  
Age Related

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier (oBRB) and is the prime target of early age-related macular degeneration (AMD). C-reactive protein (CRP), a serum biomarker for chronic inflammation and AMD, presents two different isoforms, monomeric (mCRP) and pentameric (pCRP), that may have a different effect on inflammation and barrier function in the RPE. The results reported in this study suggest that mCRP but not pCRP impairs RPE functionality by increasing paracellular permeability and disrupting the tight junction proteins ZO-1 and occludin in RPE cells. Additionally, we evaluated the effect of drugs commonly used in clinical settings on mCRP-induced barrier dysfunction. We found that a corticosteroid (methylprednisolone) and an anti-VEGF agent (bevacizumab) prevented mCRP-induced ARPE-19 barrier disruption and IL-8 production. Furthermore, bevacizumab was also able to revert mCRP-induced IL-8 increase after mCRP stimulation. In conclusion, the presence of mCRP within retinal tissue may lead to disruption of the oBRB, an effect that may be modified in the presence of corticosteroids or anti-VEGF drugs.

scholarly journals Oxidative stress-mediated TXNIP loss causes RPE dysfunction

2019 ◽  
Vol 51 (10) ◽  
pp. 1-13 ◽  
Author(s):  
Min Ji Cho ◽  
Sung-Jin Yoon ◽  
Wooil Kim ◽  
Jongjin Park ◽  
Jangwook Lee ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Common Factor ◽  
Age Related Macular Degeneration ◽  
Autophagic Flux ◽  
Blood Retinal Barrier ◽  
Rpe Cells ◽  
Age Related

Abstract The disruption of the retinal pigment epithelium (RPE), for example, through oxidative damage, is a common factor underlying age-related macular degeneration (AMD). Aberrant autophagy also contributes to AMD pathology, as autophagy maintains RPE homeostasis to ensure blood–retinal barrier (BRB) integrity and protect photoreceptors. Thioredoxin-interacting protein (TXNIP) promotes cellular oxidative stress by inhibiting thioredoxin reducing capacity and is in turn inversely regulated by reactive oxygen species levels; however, its role in oxidative stress-induced RPE cell dysfunction and the mechanistic link between TXNIP and autophagy are largely unknown. Here, we observed that TXNIP expression was rapidly downregulated in RPE cells under oxidative stress and that RPE cell proliferation was decreased. TXNIP knockdown demonstrated that the suppression of proliferation resulted from TXNIP depletion-induced autophagic flux, causing increased p53 activation via nuclear localization, which in turn enhanced AMPK phosphorylation and activation. Moreover, TXNIP downregulation further negatively impacted BRB integrity by disrupting RPE cell tight junctions and enhancing cell motility by phosphorylating, and thereby activating, Src kinase. Finally, we also revealed that TXNIP knockdown upregulated HIF-1α, leading to the enhanced secretion of VEGF from RPE cells and the stimulation of angiogenesis in cocultured human retinal microvascular endothelial cells. This suggests that the exposure of RPE cells to sustained oxidative stress may promote choroidal neovascularization, another AMD pathology. Together, these findings reveal three distinct mechanisms by which TXNIP downregulation disrupts RPE cell function and thereby exacerbates AMD pathogenesis. Accordingly, reinforcing or restoring BRB integrity by targeting TXNIP may serve as an effective therapeutic strategy for preventing or attenuating photoreceptor damage in AMD.

Intrachoroidal Dye Leakage in Indocyanine Green Fundus Angiography after Experimental Commotio Retinae

1992 ◽  
Vol 2 (2) ◽  
pp. 79-82 ◽  
Author(s):  
T. Miki ◽  
K. Kitashoji ◽  
T. Kohno
Keyword(s):  
Indocyanine Green ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Molecular Size ◽  
Sodium Fluorescein ◽  
Blood Retinal Barrier ◽  
Rabbit Eye ◽  
Icg Angiography ◽  
Commotio Retinae ◽  
Choroidal Vessels

Dye leakage in sodium fluorescein (FLUO) fundus angiography indicates damage to the blood-retinal barrier. However, dye leakage in indocyanine green (ICG) fundus angiography does not mean the same, because of the larger molecular size of the dye and impermeability of the choroidal vessels to it. The possibility of dye leakage in ICG angiography has not yet been revealed in an experimental study in which the blood-retinal barrier is undamaged. We report here that intrachoroidal dye leakage may occur in ICG angiography in an experimental model of the traumatic retinal opacity of the rabbit eye, even when the blood-retinal barrier is undamaged. This mechanism of dye leakage in ICG angiography is quite different from the leakage of FLUO angiography. Pathological choroidal vessels with increased permeability, such as choroidal neovascularization under the retinal pigment epithelium, can be observed using ICG angiography.

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