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ATF6 is a key regulator of the unfolded protein response (UPR) pathway that maintains cellular homeostasis during ER stress. In people, loss of ATF6 function causes cone dysfunction, manifesting as achromatopsia (ACHM). Previously, we generated ACHM retinal organoids (ROs) from patient induced pluripotent stem cells (iPSCs) carrying mutant ATF6 variants and gene-edited ATF6-knockout (KO) human embryonic stem cells (hESCs). ACHM and ATF6-KO ROs both showed severe stunting of cone inner and outer segments. RNA-Seq analysis of ACHM 290-day-old ROs showed downregulated cone gene expression and dysregulated mitochondria and ER stress gene expression. Here, we analyzed RNA-Seq analysis of 203-day-old ATF6-KO ROs. In younger ROs, we found dysregulation of genes involved in retinal and photoreceptor structural integrity, including CRB1, EGFLAM, and VTN. In addition, we found dysregulation of ATF6 and UPR-regulated transcriptional signatures. Dysregulation of retinal and photoreceptor structural integrity genes may underlie the observed stunting of cone inner/outer segments in ATF6-achromatopsia patients.
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http://dx.doi.org/10.1007/978-3-031-76550-6_66 | DOI Listing |
Ann Anat
September 2025
Department of Biology, Faculty of Arts and Sciences, Burdur Mehmet Akif Ersoy University, Burdur, Turkey.
The Anatolian ground squirrel (Spermophilus xanthoprymnus) offers a valuable model for investigating neuroadaptive processes in the retina during hibernation. This study aimed to assess the expression of vesicular glutamate transporter 1 (VGLUT1), glutamic acid decarboxylase (GAD) isoforms GAD65 and GAD67, and microtubule-associated protein 2 (MAP2) in the retina during pre-hibernation and hibernation states. Retinal tissues were analyzed using immunohistochemistry and densitometric quantification.
View Article and Find Full Text PDFExp Eye Res
September 2025
Department of Ophthalmology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Henan Eye Hospital, Zhengzhou, Henan, China; Henan Key Laboratory of Ophthalmology and Visual Science, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan, China; Eye institu
Bardet-Biedl Syndrome (BBS) is a rare autosomal recessive ciliopathy characterized by genetic heterogeneity. Despite significant progress in understanding the BBSome-coding genes associated with ciliopathies, the pathogenesis linked to mutations in chaperonin-coding genes (BBS6, BBS10, and BBS12) remains poorly defined. This study aims to confirm the genetic diagnosis of BBS and elucidate the pathological mechanisms in causative genes of BBS10 and BBS12.
View Article and Find Full Text PDFActa Biomater
September 2025
Faculty of medicine and health technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland. Electronic address:
In the eye, the retinal pigment epithelium (RPE) maintains the functionality and welfare of retinal photoreceptors and forms a tight, interlocked structure with photoreceptor outer segments (POSs). The RPE-retina interaction is difficult to recapitulate in vitro, limiting the studies addressing the retinal maintenance functions of the RPE. To overcome this challenge, we constructed a retina-mimicking structure using a soft polyacrylamide hydrogel coated with Matrigel.
View Article and Find Full Text PDFMutations in the gene in Stargardt disease (STGD1) cause enhanced accumulation of cytotoxic lipofuscin, manifesting in RPE atrophy and photoreceptor dysfunction. One component of lipofuscin is the all--retinal derivative, pyridinium bisretinoid A2E. Since ocular A2E biosynthesis relies on all--retinal, which is obtained from circulating all--retinol bound to retinol binding protein 4 (RBP4-ROL), we hypothesized that modulating vitamin A receptors, such as RBPR2, which regulate serum RBP4-ROL homeostasis, should in principle attenuate A2E production.
View Article and Find Full Text PDFNat Microbiol
September 2025
Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
Microbial rhodopsins are photoreceptor proteins widely distributed in marine microorganisms that harness light energy and support marine ecosystems. While retinal is typically the sole chromophore in microbial rhodopsins, some proteorhodopsins, which are proton-pumping rhodopsins abundant in the ocean, use carotenoid antennae to transfer light energy to retinal. However, the mechanism by which carotenoids enhance rhodopsin functions remains unclear.
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