Dataset Information

Endoplasmic Reticulum Stress and the Lysosomal Pathway Play Crucial Roles in the Progression of βB2-Crystallin Mutation-Induced Congenital Cataracts in Mice.

ABSTRACT:

Purpose

Congenital cataract is a major cause of visual impairment and childhood blindness; however, its underlying mechanism remains unclear. Here, we aimed to identify the roles of endoplasmic reticulum stress (ERS), lysosomal pathway, and lens capsule fibrosis during the progression of βB2-crystallin mutation-induced congenital cataract in mice.

Methods

BetaB2-W151C knock-in mice were generated using the CRISPR/Cas9 system. Lens opacity was assessed with a slit-lamp biomicroscopy and dissecting microscope. Transcriptional profiles of the lenses in W151C mutant and wild-type (WT) control mice were detected at 3 months of age. Immunofluorescence of lens anterior capsule was photographed with a confocal microscope. Real-time PCR and immunoblot were used to detect gene mRNA and protein expressions, respectively.

Results

BetaB2-W151C knock-in mice developed progressive bilateral congenital cataracts. At 2 to 3 months of age, lens opacity rapidly progressed to complete cataracts. Additionally, multilayered LEC plaques developed beneath the lens anterior capsule in homozygous mice at 3 months of age, and severe fibrosis was observed in the whole lens capsule at 9 months of age. Microarray analysis of whole genome transcriptomics and the validation results of real-time PCR revealed that genes of ERS, the lysosomal pathway, apoptosis, and cell migration and fibrosis were significantly upregulated in βB2-W151C mutant mice during the accelerated development of cataract. Moreover, the syntheses of various crystallins stagnated in βB2-W151C mutant mice.

Conclusions

ERS, the lysosomal pathway, apoptosis, and fibrosis all contributed to the accelerated development of congenital cataract. The inhibition of ERS and lysosomal cathepsins may be promising therapeutic strategies for congenital cataract.

SUBMITTER: Xiao W

PROVIDER: S-EPMC10150832 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature

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Publications

Endoplasmic Reticulum Stress and the Lysosomal Pathway Play Crucial Roles in the Progression of βB2-Crystallin Mutation-Induced Congenital Cataracts in Mice.

Xiao Wei W Yang Weimin W Zhang Xinyu X Deng Xiaoqian X Chen Xiaoyun X

Investigative ophthalmology & visual science 20230401 4

<h4>Purpose</h4>Congenital cataract is a major cause of visual impairment and childhood blindness; however, its underlying mechanism remains unclear. Here, we aimed to identify the roles of endoplasmic reticulum stress (ERS), lysosomal pathway, and lens capsule fibrosis during the progression of βB2-crystallin mutation-induced congenital cataract in mice.<h4>Methods</h4>BetaB2-W151C knock-in mice were generated using the CRISPR/Cas9 system. Lens opacity was assessed with a slit-lamp biomicroscop ...[more]

PMID: 37103007

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Project description:PurposeTo identify mutations in crystallin genes in Chinese families with congenital cataracts.MethodsForty-two unrelated families with non-syndromic congenital cataracts were enrolled in this study. The coding exons and adjacent intronic regions of crystallin genes, including CRYAA, CRYAB, CRYBA1, CRYBA4, CRYBB1, CRYBB2, CRYBB3, CRYGC, CRYGD and CRYGS, were analyzed with Sanger sequencing. Novel variants were further evaluated in 112 ethnically matched controls. To confirm the novel mutations, short tandem repeat (STR) haplotypes were constructed to check the cosegregation with congenital cataract. The pathogenic potential of the novel mutations were assessed using bioinformatics tools, including Sorting Intolerant From Tolerant v5.1.1 (SIFT), Polymorphism Phenotyping v2 (PolyPhen-2), and Human Splicing Finder. The pathogenicity of all the mutations was evaluated according to the guidelines of the American College of Medical Genetics (ACMG) and InterVar software.ResultsSeven previously reported mutations in crystallin genes identified in ten unrelated families were associated with the congenital nuclear cataracts. Four novel mutations in crystallin genes, including c.35G>T (p.R12L) in CRYAA, c.463C>A (p.Q155K) in CRYBB2, IVS1 c.10-1G>A in CRYGC, and c.346delT (p.F116Sfsx29) in CRYGD, were identified in four unrelated families with congenital cataracts. These mutations cosegregated with all affected individuals in each family were not observed in the unaffected family members or in the 112 unrelated controls. All four novel mutations were categorized as disease "likely pathogenic" except IVS1 c.10-1G>A in CRYGC "pathogenic" using InterVar software in accordance with the ACMG standard. Mutations in crystallin genes were responsible for 33.33% of the Chinese families with congenital cataracts in this cohort.ConclusionsIn this study, we identified four novel mutations in crystallin genes in Chinese families with congenital cataracts. The results expand the mutational spectrum of crystallin genes, which may be helpful for the molecular diagnosis of congenital cataracts in the era of precision medicine.

Project description:The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.

Dataset Information

Endoplasmic Reticulum Stress and the Lysosomal Pathway Play Crucial Roles in the Progression of βB2-Crystallin Mutation-Induced Congenital Cataracts in Mice.

Purpose

Methods

Results

Conclusions

Publications

Endoplasmic Reticulum Stress and the Lysosomal Pathway Play Crucial Roles in the Progression of βB2-Crystallin Mutation-Induced Congenital Cataracts in Mice.

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