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

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

doi:10.3390/cells11213462

Cited by 15 publications

(33 citation statements)

References 65 publications

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“…ABCA4 is a membrane protein of the OS of PRs, however, cultured cells do not have an OS and some OS membrane proteins, like RHO 44 , are localized predominantly on the plasma membrane when heterologously expressed. ABCA4 has been reported to localize to the cell surface in HEK293T cells 40,45 , and in RPE cells derived from iPSCs 46,47 . Therefore, the plasma membrane localization of WT-ABCA4 and missense variants was investigated.…”

Section: Resultsmentioning

confidence: 99%

A proximity complementation assay to identify small molecules that enhance the traffic of ABCA4 misfolding variants

Piccolo,

Zarouchlioti,

Bellingham

et al. 2024

Preprint

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ABCA4–related–retinopathy is the most common inherited Mendelian eye disorder worldwide, caused by biallelic variants in the ATP-binding cassette transporter ABCA4. To date, over 2,200 ABCA4 variants have been identified, including missense, nonsense, indels, splice site and deep intronic defects. Notably, more than 60% are missense variants that can lead to protein misfolding, mistrafficking and degradation. Currently no approved therapies target ABCA4. In this study, we demonstrate that ABCA4 misfolding variants are temperature-sensitive and reduced temperature growth (30°C) improves their traffic to the plasma membrane, suggesting the folding of these variants could be rescuable. Consequently, an in vitro platform was developed for the rapid and robust detection of ABCA4 traffic to the plasma membrane in transiently transfected cells. The system was used to assess selected candidate small molecules that were reported to improve the folding or traffic of other ABC transporters. Two candidates, 4–PBA and AICAR, were identified and validated for their ability to enhance both wild-type ABCA4 and variant trafficking to the cell surface in cell culture. We envision that this platform could serve as a primary screen for more sophisticated in vitro testing, enabling the discovery of breakthrough agents to rescue ABCA4 protein defects and mitigate ABCA4–related–retinopathy.

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Section: Resultsmentioning

confidence: 99%

A proximity complementation assay to identify small molecules that enhance the traffic of ABCA4 misfolding variants

Piccolo,

Zarouchlioti,

Bellingham

et al. 2024

Preprint

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“…70 Abca4 is also an important membrane-associated protein involved in retinal metabolism. 71 Relatively little is known about Btbd17 , but it is also expressed in the brain and is predicted to localize in the plasma membrane. 72 Genes expressed early in pseudotime that declined in expression during development included Btg1 , R3hdml , and Birc5 (survivin) ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Single-Cell RNA Sequencing Analysis of the Early Postnatal Mouse Lens Epithelium

Giannone,

Sellitto,

Rosati

et al. 2023

Invest. Ophthalmol. Vis. Sci.

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Purpose The lens epithelium maintains the overall health of the organ. We used single-cell RNA sequencing (scRNA-seq) technology to assess transcriptional heterogeneity between cells in the postnatal day 2 (P2) epithelium and identify distinct epithelial cell subtypes. Analysis of these data was used to better understand lens growth, differentiation, and homeostasis on P2. Methods scRNA-seq on P2 mouse lenses was performed using the 10x Genomics Chromium Single Cell 3′ Kit (v3.1) and short-read Illumina sequencing. Sequence alignment and preprocessing of data were conducted using 10x Genomics Cell Ranger software. Seurat was employed for preprocessing, quality control, dimensionality reduction, and cell clustering, and Monocle was utilized for trajectory analysis to understand the developmental progression of the lens cells. CellChat and GO analyses were used to explore cell–cell communication networks and signaling interactions. Results Lens epithelial cells (LECs) were divided into seven subclusters, classified by specific gene markers. The expression of crystallin, cell-cycle, and metabolic genes was not uniform, indicating distinct functional roles of LECs. Trajectory analysis predicted a bifurcation of differentiating and cycling cells from an Igfbp5+ progenitor pool. We also identified heterogeneity in signaling molecules and pathways, suggesting that cycling and progenitor subclusters have prominent roles in coordinating crosstalk. Conclusions scRNA-seq corroborated many known markers of epithelial differentiation and proliferation while providing further insight into the pathways and genes directing these processes. Interestingly, we demonstrated that the developing epithelium can be divided into distinct subpopulations. These clusters reflect the transcriptionally diverse roles of the epithelium in proliferation, signaling, and maintenance.

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“…Eight days post-intervention, photoreceptor outer segment loss was noted and likely attributed to the deposition of membrane attack complexes on it. Prior studies have reported that the formation of membrane attack complexes on RPE cells leads to cell lysis [58,59]. At 9 days post-intervention, RPE loss and hypopigmentation were also observed.…”

Section: C3-overexpressed Mouse Modelmentioning

confidence: 86%

Dysfunctional Autophagy, Proteostasis, and Mitochondria as a Prelude to Age-Related Macular Degeneration

Lenin,

Koh,

Zhang

et al. 2023

IJMS

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Retinal pigment epithelial (RPE) cell dysfunction is a key driving force of AMD. RPE cells form a metabolic interface between photoreceptors and choriocapillaris, performing essential functions for retinal homeostasis. Through their multiple functions, RPE cells are constantly exposed to oxidative stress, which leads to the accumulation of damaged proteins, lipids, nucleic acids, and cellular organelles, including mitochondria. As miniature chemical engines of the cell, self-replicating mitochondria are heavily implicated in the aging process through a variety of mechanisms. In the eye, mitochondrial dysfunction is strongly associated with several diseases, including age-related macular degeneration (AMD), which is a leading cause of irreversible vision loss in millions of people globally. Aged mitochondria exhibit decreased rates of oxidative phosphorylation, increased reactive oxygen species (ROS) generation, and increased numbers of mitochondrial DNA mutations. Mitochondrial bioenergetics and autophagy decline during aging because of insufficient free radical scavenger systems, the impairment of DNA repair mechanisms, and reductions in mitochondrial turnover. Recent research has uncovered a much more complex role of mitochondrial function and cytosolic protein translation and proteostasis in AMD pathogenesis. The coupling of autophagy and mitochondrial apoptosis modulates the proteostasis and aging processes. This review aims to summarise and provide a perspective on (i) the current evidence of autophagy, proteostasis, and mitochondrial dysfunction in dry AMD; (ii) current in vitro and in vivo disease models relevant to assessing mitochondrial dysfunction in AMD, and their utility in drug screening; and (iii) ongoing clinical trials targeting mitochondrial dysfunction for AMD therapeutics.

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

Cited by 15 publications

References 65 publications

A proximity complementation assay to identify small molecules that enhance the traffic of ABCA4 misfolding variants

A proximity complementation assay to identify small molecules that enhance the traffic of ABCA4 misfolding variants

Single-Cell RNA Sequencing Analysis of the Early Postnatal Mouse Lens Epithelium

Dysfunctional Autophagy, Proteostasis, and Mitochondria as a Prelude to Age-Related Macular Degeneration

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