2026-05-06 | Independent Degeneration of Photoreceptors and Retinal Pigment Epithelium: Multimodal Imaging Evidence From Choroideremia Carriers.
To characterize retinal structural alterations and elucidate underlying pathogenesis in female carriers of choroideremia (CHM) using multimodal imaging. This single-center retrospective study analyzed 100 eyes of 50 genetically confirmed female CHM carriers. Clinical evaluation comprised genotype, age, visual acuity, color fundus photography, fundus autofluorescence (FAF), infrared reflectance, and optical coherence tomography (OCT). Retinal lesions were identified and classified using point-to-point co-localization analysis across modalities. The mean age of carriers was 39.6 ± 17.8 years (range 3.2-80.3 years). All eyes exhibited varying degrees of retinal abnormalities. Most common findings included yellowish changes on color photographs, mottled areas of hyper- and hypo-autofluorescence on FAF, and isolated interdigitation zone (IZ) loss on OCT. Chorioretinal atrophy beyond the peripapillary region, indicating a severe phenotype, was observed in 18% of eyes. Five characteristic degenerative lesions were identified: Type A, isolated IZ loss; Type B, hyper-autofluorescent spots corresponding to presumed photoreceptor loss; Type C, drusen-like deposits; Type D, degeneration of the retinal pigment epithelium (RPE) and RPE-photoreceptor interface; and Type E, outer retinal degeneration. Type B lesions suggest that photoreceptor loss may precede RPE loss at specific loci. Type A lesions were the earliest abnormality, significantly associated with milder phenotypes, indicating the RPE-photoreceptor interface is the initial site of pathology. In contrast, Type D and E lesions were associated with severe phenotypes. Identified hyper-autofluorescence lesions corresponding to presumed photoreceptor loss indicate independent degeneration of photoreceptors and RPE. These findings suggest that future therapeutic approaches should concurrently target both cellular components.
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2026-03-31 | REP-1 deficiency induces aberrant mitochondrial metabolic rewiring from glycolysis to lipid oxidation in CHM disease.
Choroideremia (CHM) is a hereditary retinal degenerative disorder characterized by progressive dysfunction of the retinal pigment epithelium (RPE) and photoreceptors with no available therapy. Despite the recognized genetic basis of CHM, the metabolic pathways driving disease progression remain poorly defined. By investigating REP-1 deficiency in CHM disease, our study reveals a previously unrecognized role for REP-1 in regulating GLUT-1 and GLUT-4 membrane trafficking, controlling glucose uptake, and reprograming mitochondrial metabolism toward lipid oxidation. This chronic metabolic shift results in reduced glycolytic flux, elevated oxidative stress, and compromised ATP production, culminating in a progressive retinal dystrophy. Notably, pharmacological restoration of GLUT trafficking via leptin administration re-established glucose uptake and mitochondrial function, rescuing cellular energetics both in vitro and in vivo. These findings establish REP-1 as a key regulator of retinal metabolic homeostasis and suggest that targeting glucose-lipid metabolic rewiring may represent a novel therapeutic strategy for CHM and related retinal dystrophies.
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2026-02-05 | Anticodon-edited transfer RNAs (ACE-tRNAs) encoded as therapeutic nonviral minimal DNA vectors.
Nonsense mutations, resulting from a premature termination codon (PTC), make up ∼11% of all genetic lesions causing disease, affecting millions of people worldwide. Nonsense suppressor anticodon-edited transfer RNAs (ACE-tRNAs) have emerged as a therapeutic modality for the rescue of PTCs. Delivery of ACE-tRNAs in vivo has been achieved by adeno-associated viral vector and RNA-lipid nanoparticle; however, due to drawbacks associated with these approaches, DNA delivery remains an attractive approach. DNA-based approaches afford ease of manufacturing at a relatively low cost and exhibit improved therapeutic durability and safety as compared to viral vector- or RNA-based approaches. Due to the small size of human tRNA genes employed as ACE-tRNAs, in principle, DNA vectors <200 base pairs (bp) in size (minivectors) could be utilized for delivery of actively transcribed ACE-tRNAs. Here, we demonstrate that linear DNA ACE-tRNA vectors as small as 200 bp effectively suppress several nonsense mutations in CFTR and REP1, and that ACE-tRNA minivectors, when tested in cell or ex vivo models, display significantly improved bioavailability, reduced innate immune burden, and superior biostability as compared to conventional plasmid DNA vectors.
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