Isolation of Photoreceptor Cell-Specific MEKA cDNA by Differential Hybridization

Abstract Calphotin is a Drosophila photoreceptor cell-specific protein expressed very early in eye development, at the time when cell-type decisions are being made. Calphotin is a very hydrophobic and proline-rich protein which lacks obvious transmembrane domains. The cDNA encoding Calphotin was mapped to a region removed by a set of existing chromosomal deletions. Mutations that alter photoreceptor cell structure and development were isolated that fail to complement these deletions. These mutations fall into two classes. Class I mutations alter the structure of the rhabdomere, a photoreceptor cell organelle specialized for phototransduction. Class II mutations have rough eyes, due to misorientation of the rhabdomeres and photoreceptor cell death. Transformation rescue of these phenotypes in transgenic flies bearing calphotin genomic DNA indicates that both classes of mutations are in the calphotin gene. Analysis of these mutations suggest that Calphotin plays important roles in both rhabdomere development and in photoreceptor cell survival.

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

Communications Biology ◽

10.1038/s42003-021-01682-5 ◽

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.

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Distinct and Atypical Intrinsic and Extrinsic Cell Death Pathways between Photoreceptor Cell Types upon Specific Ablation of Ranbp2 in Cone Photoreceptors

PLoS Genetics ◽

10.1371/journal.pgen.1003555 ◽

2013 ◽

Vol 9 (6) ◽

pp. e1003555 ◽

Cited By ~ 21

Author(s):

Kyoung-in Cho ◽

MdEmdadul Haque ◽

Jessica Wang ◽

Minzhong Yu ◽

Ying Hao ◽

...

Keyword(s):

Cell Death ◽

Photoreceptor Cell ◽

Cell Types ◽

Cone Photoreceptors ◽

Cell Death Pathways

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Adiponectin receptor 1 conserves docosahexaenoic acid and promotes photoreceptor cell survival

Nature Communications ◽

10.1038/ncomms7228 ◽

2015 ◽

Vol 6 (1) ◽

Cited By ~ 42

Author(s):

Dennis S. Rice ◽

Jorgelina M. Calandria ◽

William C. Gordon ◽

Bokkyoo Jun ◽

Yongdong Zhou ◽

...

Keyword(s):

Docosahexaenoic Acid ◽

Opposite Effect ◽

Photoreceptor Cell ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Adiponectin Receptor ◽

Cell Integrity ◽

Photoreceptor Degeneration ◽

Adiponectin Receptor 1

Abstract The identification of pathways necessary for photoreceptor and retinal pigment epithelium (RPE) function is critical to uncover therapies for blindness. Here we report the discovery of adiponectin receptor 1 (AdipoR1) as a regulator of these cells’ functions. Docosahexaenoic acid (DHA) is avidly retained in photoreceptors, while mechanisms controlling DHA uptake and retention are unknown. Thus, we demonstrate that AdipoR1 ablation results in DHA reduction. In situ hybridization reveals photoreceptor and RPE cell AdipoR1 expression, blunted in AdipoR1−/− mice. We also find decreased photoreceptor-specific phosphatidylcholine containing very long-chain polyunsaturated fatty acids and severely attenuated electroretinograms. These changes precede progressive photoreceptor degeneration in AdipoR1−/− mice. RPE-rich eyecup cultures from AdipoR1−/− reveal impaired DHA uptake. AdipoR1 overexpression in RPE cells enhances DHA uptake, whereas AdipoR1 silencing has the opposite effect. These results establish AdipoR1 as a regulatory switch of DHA uptake, retention, conservation and elongation in photoreceptors and RPE, thus preserving photoreceptor cell integrity.

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