In contrast to the mammalian retina, the zebrafish retina possesses the ability to regenerate. This is primarily accomplished through Müller glial cells, which, upon damage, re-enter the cell cycle to form retinal progenitors. The progenitors continue to proliferate as they migrate to the area of damage and ultimately differentiate into new neurons. The purpose of this study was to characterize the expression and function of Sonic Hedgehog (Shh) during regeneration of the adult zebrafish retina. Expression profiling of Shh pathway genes showed a significant upregulation of expression associated with stages of progenitor proliferation and neuronal differentiation. Activation of Shh signaling during early stages of retinal regeneration using intraocular injections of the recombinant human SHH (SHH-N) resulted in increased Müller cell gliosis, proliferation, and neuroprotection of damaged retinal neurons. Continued activation of Shh resulted in a greater number of differentiated amacrine and ganglion cells in the fully regenerated retina. Conversely, inhibition of Shh signaling using intraocular injections of cyclopamine resulted in decreased Müller glial cell proliferation and a fewer number of regenerated amacrine and ganglion cells. These data suggest that Shh signaling plays pleiotropic roles in proliferation and differentiation during adult zebrafish retinal regeneration.
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http://dx.doi.org/10.1016/j.exer.2017.10.003 | DOI Listing |
Front Neurol
January 2025
Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun, China.
Retinal ganglion cells (RGCs) generally fail to regenerate axons, resulting in irreversible vision loss after optic nerve injury. While many studies have shown that modulating specific genes can enhance RGCs survival and promote optic nerve regeneration, inducing long-distance axon regeneration through single-gene manipulation remains challenging. Nevertheless, combined multi-gene therapies have proven effective in significantly enhancing axonal regeneration.
View Article and Find Full Text PDFMol Genet Genomic Med
January 2025
Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
Background: Leber congenital amaurosis (LCA), the most severe form of inherited retinal dystrophy, is a rare, heterogeneous, genetic eye disease associated with severe congenital visual impairment. RPE65, one of the causative genes for LCA, encodes retinoid isomerohydrolase, an enzyme that plays a critical role in regenerating visual pigment in photoreceptor cells.
Methods: Exome sequencing (ES) was performed on a patient with suspected LCA.
Proc Natl Acad Sci U S A
January 2025
Department of Biological Structure, University of Washington, Seattle, WA 98125.
Retinal diseases often lead to degeneration of specific retinal cell types with currently limited therapeutic options to replace the lost neurons. Previous studies have reported that overexpression of or combinations of proneural factors in Müller glia (MG) induce regeneration of functional neurons in the adult mouse retina. Recently, we applied the same strategy in dissociated cultures of fetal human MG and although we stimulated neurogenesis from MG, our effect in 2D cultures was modest and our analysis of newborn neurons was limited.
View Article and Find Full Text PDFAlzheimers Dement (Amst)
January 2025
Introduction: We explored associations between measurements of the ocular choroid microvasculature and Alzheimer's disease (AD) risk.
Methods: We measured the choroidal vasculature appearing in optical coherence tomography (OCT) scans of 69 healthy, mid-life individuals in the PREVENT Dementia cohort. The cohort was prospectively split into low-, medium-, and high-risk groups based on the presence of known risk factors (apolipoprotein E [] ε4 genotype and family history of dementia [FH]).
Adv Sci (Weinh)
January 2025
Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology&Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Key Laboratory of the Ministry of Industry and Information Technology, Beijing Key Laboratory of Intelligent Diagnosis, Treatment and Prevention of Blinding Eye Diseases, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
Retinal diseases can severely impair vision and even lead to blindness, posing significant threats to both physical and mental health. Physical retinal regenerative therapies are poised to revolutionize the treatment of various disorders associated with blindness. However, these therapies must overcome the challenges posed by the protective inner and outer blood‒retinal barriers.
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