bims-mideyd 2022-11-13 papers

bims-mideyd

Biomed News

on Mitochondrial dysfunction in eye diseases

Issue of 2022–11–13
nine papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Regulation of oxidative stress and inflammatory responses in human retinal pigment epithelial cells.
Oxidative stress alters transcript localization of disease-associated genes in the retinal pigment epithelium.
Membrane Blue Dual Protects Retinal Pigment Epithelium Cells/Ganglion Cells-Like through Modulation of Mitochondria Function.
Molecular and Functional Characterization of BDNF-Overexpressing Human Retinal Pigment Epithelial Cells Established by Sleeping Beauty Transposon-Mediated Gene Transfer.
Oxidative Stress-Induced Cellular Senescence in Aging Retina and Age-Related Macular Degeneration.
Sustained release of heme-albumin as a potential novel therapeutic approach for age-related macular degeneration.
Sulforaphane recovers cone function in an Nrf2-dependent manner in middle-aged mice undergoing RPE oxidative stress.
Maprotiline restores ER homeostasis and rescues neurodegeneration via Histamine Receptor H1 inhibition in retinal ganglion cells.
Membrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration.

Acta Ophthalmol. 2022 Nov;100 Suppl 273 3-59

Regulation of oxidative stress and inflammatory responses in human retinal pigment epithelial cells.

Niina Harju.

  Age-related macular degeneration (AMD) is an eye disease, which causes impaired vision that can lead to blindness. The incidence of AMD increases with age. Retinal pigment epithelial (RPE) cells maintain retinal homeostasis and support the functionality of photoreceptors. In the pathogenesis of AMD, the degeneration of the RPE cells precedes photoreceptor cell death. RPE cells are susceptible to oxidative stress, and chronic inflammation involving nucleotide-binding domain, leucine-rich repeat and pyrin domain 3 (NLRP3) inflammasome activation and impaired autophagy are challenges faced by aged RPE cells in AMD. There are two types of AMD, dry (85-90%) and wet (10-15%) disease forms. Choroidal neovascularization is typical for wet AMD, and anti-vascular endothelial growth factor (anti-VEGF) injections are used to prevent the progression of the disease but there is no curative treatment. There is no cure for the dry disease form, but antioxidants have been proposed as a potential treatment option. Ageing is the most important risk factor of AMD, and tobacco smoke is the most important environmental risk factor that can be controlled. Hydroquinone is a cytotoxic, immunotoxic, carcinogenic and pro-oxidative component of tobacco smoke. The aim of this PhD thesis was to study hydroquinone-induced oxidative stress and NLRP3 inflammasome activation in human RPE cells (ARPE-19 cells). An age-related eye disease study (AREDS) formulation (incl. omega-3 fatty acids, vitamin C and E, copper, zinc, lutein and zeaxanthin), which is clinically investigated p.o. dosing combination of dietary supplements for AMD patients, has been evaluated as a possible treatment and restraining option for AMD. Resvega (4.1.1, Table 2) is a similar kind of product to AREDS with added resveratrol, and many of the components incorporated within Resvega can be considered as belonging to the normal antioxidative defence system of the retina. Another aim was to evaluate the effects of Resvega on hydroquinone-induced oxidative stress or NLRP3 inflammasome activation induced by impaired protein clearance. The results of this study reveal that hydroquinone elevated the activity of NADPH oxidase which subsequently mediated the production of reactive oxygen species (ROS) and predisposed RPE cells to degeneration by reducing levels of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF). Hydroquinone induced an NLRP3-independent IL-18 release and NLRP3 accumulation inside the IL-1α-primed cells. Resvega treatment reduced the extent of hydroquinone-induced ROS production and NLRP3 inflammasome activation evoked by impaired protein clearance. Thus, Resvega alleviated hydroquinone- and impaired protein clearance-induced stress in human RPE cells, but more studies are needed, for example, to reveal the most optimal route of administration for targeting the cells in the retina, since both oxidative stress and NLRP3 inflammasome activation are important contributors to the development of AMD and represent significant treatment targets.

Keywords:  AMD; ARPE-19 cell; ARPE-19 solu; NLRP3; PEDF; ROS; RPE cell; RPE-solu; Resvega; VEGF; cytokines; hydrokinoni; hydroquinone; sytokiinit

DOI:  https://doi.org/10.1111/aos.15275
Mol Vis. 2022 ;28 340-351

Oxidative stress alters transcript localization of disease-associated genes in the retinal pigment epithelium.

Tadeusz J Kaczynski, Elizabeth D Au, Michael H Farkas.

Purpose: Nuclear retention is a mechanism whereby excess RNA transcripts are stored in the event that a cell needs to quickly respond to a stimulus; maintaining proper nuclear-to-cytoplasmic balance is important for cellular homeostasis and cell function. There are many mechanisms that are employed to determine whether to retain a transcript or export it to the cytoplasm, although the extent to which tissue or cell type, internal and external stressors, and disease pathogenesis affect this process is not yet clear. As the most biochemically active tissue in the body, the retina must mitigate endogenous and exogenous stressors to maintain cell health and tissue function. Oxidative stress, believed to contribute to the pathogenesis or progression of age-related macular degeneration (AMD) and inherited retinal dystrophies (IRDs), is produced both internally from biochemical processes as well as externally from environmental insult. Here, we evaluate the effect of oxidative stress on transcript localization in the retinal pigment epithelium (RPE), with specific focus on transcripts related to RPE function and disease.
Methods: We performed poly(A) RNA sequencing on nuclear and cytoplasmic fractions from human induced pluripotent stem cell-derived retinal pigment epithelium (iPSC-RPE) cells exposed to hydrogen peroxide (H2O2), as well as on untreated controls.
Results: Under normal conditions, the number of mRNA transcripts retained in the nucleus exceeded that found in studies on other tissues. Further, the nuclear-to-cytoplasmic ratio of transcripts was altered following oxidative stress, as was the retention of genes associated with AMD and IRDs, as well as those that are important for RPE physiology.
Conclusions: These results provide a localization catalog of all expressed mRNA in iPSC-RPE under normal conditions and after exposure to H2O2, shedding light on the extent to which H2O2 alters transcript localization and potentially offering insight into one mechanism through which oxidative stress may contribute to the progression of visual disorders.
Biomedicines. 2022 Nov 08. pii: 2854. [Epub ahead of print]10(11):

Membrane Blue Dual Protects Retinal Pigment Epithelium Cells/Ganglion Cells-Like through Modulation of Mitochondria Function.

Elena Grossini, Sakthipriyan Venkatesan, Micol Alkabes, Caterina Toma, Stefano de Cillà.

  Although recent data highlight the greater protective effects exerted by Membrane Blue Dual (MBD), a precise analysis of the mechanisms of action is missing. We examined the effects of MBD with/without polyethylene glycol (PEG) on both human retinal pigment epithelial cells (ARPE-19) and retinal ganglion cells-like (RGC-5) cultured in the presence/absence of ultraviolet B (UVB) treatment on mitochondria function, oxidants, and apoptosis. In ARPE-19/RGC-5 cells either treated or not with UVB, the effects of MBD with/without PEG were evaluated by specific assays for viability, mitochondrial membrane potential and mitochondrial reactive oxygen species (mitoROS) release. Annexin V was used to detect apoptosis, whereas trypan blue and the scratch assay were used for proliferation/migration. In both physiologic conditions and in the presence of UVB, MBD with/without PEG increased cell viability, mitochondrial membrane potential, proliferation and migration in both ARPE-19 and RGC-5 cells. In general, the effects of MBD with PEG were greater than those caused by MBD without PEG. Our results suggest that, in particular, MBD with PEG is a safe and effective dye for vitreoretinal surgery through the modulation of mitochondrial function.

Keywords:  mitochondria; oxidative stress; vital dyes; vitrectomy

DOI:  https://doi.org/10.3390/biomedicines10112854
Int J Mol Sci. 2022 Oct 26. pii: 12982. [Epub ahead of print]23(21):

Molecular and Functional Characterization of BDNF-Overexpressing Human Retinal Pigment Epithelial Cells Established by Sleeping Beauty Transposon-Mediated Gene Transfer.

Larissa Mattern, Katrin Otten, Csaba Miskey, Matthias Fuest, Zsuzsanna Izsvák, Zoltán Ivics, Peter Walter, Gabriele Thumann, Sandra Johnen.

  More and more patients suffer from multifactorial neurodegenerative diseases, such as age-related macular degeneration (AMD). However, their pathological mechanisms are still poorly understood, which complicates the development of effective therapies. To improve treatment of multifactorial diseases, cell-based gene therapy can be used to increase the expression of therapeutic factors. To date, there is no approved therapy for dry AMD, including late-stage geographic atrophy. We present a treatment option for dry AMD that transfers the brain-derived neurotrophic factor (BDNF) gene into retinal pigment epithelial (RPE) cells by electroporation using the plasmid-based Sleeping Beauty (SB) transposon system. ARPE-19 cells and primary human RPE cells were co-transfected with two plasmids encoding the SB100X transposase and the transposon carrying a BDNF transcription cassette. We demonstrated efficient expression and secretion of BDNF in both RPE cell types, which were further increased in ARPE-19 cell cultures exposed to hydrogen peroxide. BDNF-transfected cells exhibited lower apoptosis rates and stimulated neurite outgrowth in human SH-SY5Y cells. This study is an important step in the development of a cell-based BDNF gene therapy that could be applied as an advanced therapy medicinal product to treat dry AMD or other degenerative retinal diseases.

Keywords:  AMD; BDNF; RPE cells; Sleeping Beauty transposon system; cell-based additive gene therapy; neurodegenerative retinal diseases; non-viral transfection

DOI:  https://doi.org/10.3390/ijms232112982
Antioxidants (Basel). 2022 Nov 05. pii: 2189. [Epub ahead of print]11(11):

Oxidative Stress-Induced Cellular Senescence in Aging Retina and Age-Related Macular Degeneration.

Ryo Terao, Tazbir Ahmed, Ayana Suzumura, Hiroko Terasaki.

  Aging leads to a gradual decline of function in multiple organs. Cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration (AMD) are age-related ocular diseases. Because their pathogenesis is unclear, it is challenging to combat age-related diseases. Cellular senescence is a cellular response characterized by cell cycle arrest. Cellular senescence is an important contributor to aging and age-related diseases through the alteration of cellular function and the secretion of senescence-associated secretory phenotypes. As a driver of stress-induced premature senescence, oxidative stress triggers cellular senescence and age-related diseases by inducing senescence markers via reactive oxygen species and mitochondrial dysfunction. In this review, we focused on the mechanism of oxidative stress-induced senescence in retinal cells and its role in the pathogenesis of AMD.

Keywords:  age-related macular degeneration; aging; cellular senescence; inflammation; oxidative stress

DOI:  https://doi.org/10.3390/antiox11112189
Biomater Sci. 2022 Nov 07.

Sustained release of heme-albumin as a potential novel therapeutic approach for age-related macular degeneration.

Megan M Allyn, Maria A Rincon-Benavides, Heather L Chandler, Natalia Higuita-Castro, Andre F Palmer, Katelyn E Swindle-Reilly.

Globally, age-related macular degeneration (AMD) is the third most common visual impairment. Most often attributed to cellular fatigue with aging, over expression of reactive oxygen species (ROS) causes ROS accumulation in the retina, leading to chronic inflammatory immune signaling, cellular and tissue damage, and eventual blindness. If left uncontrolled, the disease will progress from the dry form of AMD to more severe forms such as geographic atrophy or wet AMD, hallmarked by choroidal neovascularization. There is no cure for AMD and treatment options are limited. Treatment options for wet AMD require invasive ocular injections or implants, yet fail to address the disease progressing factors. To provide more complete treatment of AMD, the application of a novel anti-inflammatory heme-bound human serum albumin (heme-albumin) protein complex delivered by antioxidant ROS scavenging polydopamine (PDA) nanoparticles (NPs) for sustained treatment of AMD was investigated. Through the induction of heme oxygenase-1 (HO-1) by heme-albumin in retinal pigment epithelial (RPE) cells, anti-inflammatory protection may be provided through the generation of carbon monoxide (CO) and biliverdin during heme catabolism. Our results show that the novel protein complex has negligible cytotoxicity towards RPE cells (ARPE-19), reduces oxidative stress in both inflammatory and ROS in vitro models, and induces a statistically significant increase in HO-1 protein expression. When incorporated into PDA NPs, heme-albumin was sustainably released for up to 6 months, showing faster release at higher oxidative stress levels. Through its ability to react with ROS, heme-albumin loaded PDA NPs showed further reduction of oxidative stress with minimal cytotoxicity. Altogether, we demonstrate that heme-albumin loaded PDA NPs reduce oxidative stress in vitro and can provide sustained therapeutic delivery for AMD treatment.

DOI: https://doi.org/10.1039/d2bm00905f
Mol Vis. 2022 ;28 378-393

Sulforaphane recovers cone function in an Nrf2-dependent manner in middle-aged mice undergoing RPE oxidative stress.

Xiaoping Qi, Dorothy A Walton, Kendra S Plafker, Michael E Boulton, Scott M Plafker.

Purpose: Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables that has therapeutic efficacy in numerous animal models of human disease, including mouse models of retinal degeneration. However, despite dozens of clinical trials, the compound remains to be tested as a clinical treatment for ocular disease. Numerous cellular activities of SFN have been identified, including the activation of Nrf2, a transcription factor that induces a battery of target gene products to neutralize oxidative and xenobiotic stresses. As Nrf2 expression and function reportedly decrease with aging, we tested whether the loss of the transcription factor limits the therapeutic efficacy of SFN against retinal degeneration.
Methods: Six- to 8-month-old wild-type and Nrf2 knockout mice were treated with SFN beginning 1 month after ribozyme-mediated knockdown of superoxide dismutase 2 (SOD2) mRNA in the RPE. The impacts of MnSOD (the protein product of SOD2) knockdown and the efficacy of SFN were evaluated using a combination of electroretinography (ERG), spectral domain optical coherence tomography (SD-OCT), and postmortem histology.
Results: SFN restored the ERG photopic b-wave suppressed by MnSOD loss in wild-type mice, but not in the Nrf2 knockout mice. In contrast, ERG scotopic a- and b-wave loss was not restored for either genotype. SFN significantly improved retinal thickness in the Nrf2 knockout mice with MnSOD knockdown, but this was not observed in the wild-type mice. In both genotypes, SFN treatment reduced morphological markers of RPE atrophy and degeneration, although these improvements did not correlate proportionally with functional recovery.
Conclusions: These findings highlight the capacity of SFN to preserve cone function, as well as the potential challenges of using the compound as a standalone treatment for age-related retinal degeneration under conditions associated with reduced Nrf2 function.
Nat Commun. 2022 Nov 10. 13(1): 6796

Maprotiline restores ER homeostasis and rescues neurodegeneration via Histamine Receptor H1 inhibition in retinal ganglion cells.

Wei Chen, Pingting Liu, Dong Liu, Haoliang Huang, Xue Feng, Fang Fang, Liang Li, Jian Wu, Liang Liu, David E Solow-Cordero, Yang Hu.

When the protein or calcium homeostasis of the endoplasmic reticulum (ER) is adversely altered, cells experience ER stress that leads to various diseases including neurodegeneration. Genetic deletion of an ER stress downstream effector, CHOP, significantly protects neuron somata and axons. Here we report that three tricyclic compounds identified through a small-scale high throughput screening using a CHOP promoter-driven luciferase cell-based assay, effectively inhibit ER stress by antagonizing their common target, histamine receptor H1 (HRH1). We further demonstrated that systemic administration of one of these compounds, maprotiline, or CRISPR-mediated retinal ganglion cell (RGC)-specific HRH1 inhibition, delivers considerable neuroprotection of both RGC somata and axons and preservation of visual function in two mouse optic neuropathy models. Finally, we determine that maprotiline restores ER homeostasis by inhibiting HRH1-mediated Ca2+ release from ER. In this work we establish maprotiline as a candidate neuroprotectant and HRH1 as a potential therapeutic target for glaucoma.

DOI: https://doi.org/10.1038/s41467-022-34682-y
Cells. 2022 Nov 02. pii: 3462. [Epub ahead of print]11(21):

Membrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration.

Eunice Sze Yin Ng, Nermin Kady, Jane Hu, Arpita Dave, Zhichun Jiang, Jacqueline Pei, Michael B Gorin, Anna Matynia, Roxana A Radu.

  Recessive Stargardt disease (STGD1) is an inherited retinopathy caused by mutations in the ABCA4 gene. The ABCA4 protein is a phospholipid-retinoid flippase in the outer segments of photoreceptors and the internal membranes of retinal pigment epithelial (RPE) cells. Here, we show that RPE cells derived via induced pluripotent stem-cell from a molecularly and clinically diagnosed STGD1 patient exhibited reduced ABCA4 protein and diminished activity compared to a normal subject. Consequently, STGD1 RPE cells accumulated intracellular autofluorescence-lipofuscin and displayed increased complement C3 activity. The level of C3 inversely correlated with the level of CD46, an early negative regulator of the complement cascade. Persistent complement dysregulation led to deposition of the membrane attack complex on the surface of RPE cells, decrease in transepithelial resistance, and subsequent cell death. These findings are strong evidence of complement-mediated RPE cell damage in STGD1, in the absence of photoreceptors, caused by reduced CD46 regulatory protein.

Keywords:  ABCA4; bisretinoid-lipofuscin; complement system; macular degeneration; recessive Stargardt disease (STGD1); retinal pigment epithelium (RPE); retinoids; “disease-in-a-dish”

DOI:  https://doi.org/10.3390/cells11213462