Smurf1 modulates Smad signaling pathway in fibrotic cataract formation [mouse_ASC]
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ABSTRACT: Purpose: TGF-β/BMP signaling pathway has a significant role in fibrotic cataract. Smurf1, a ubiquitin protein ligase, regulates the TGF-β/BMP signaling pathway through the ubiquitin-proteasome system (UPS). This study aims to investigate the role of Smurf1 in the progression of fibrotic cataract and its underlying mechanism.Method: We employed a mouse injury-induced anterior subcapsular cataract (ASC) model and administered Smurf1 inhibitor A01 through anterior chamber injection for in vivo investigation. RNA sequencing was performed to examine global gene expression changes. The volume of the subcapsular opacity was determined using whole-mount immunofluorescence of lens anterior capsules. Lentivirus was utilized to create cell lines with Smurf1 knockdown or overexpression in SRA01/04. Protein levels were assessed by Simple Western. Lens epithelial cell (LEC) proliferation was evaluated by CCK8 and EdU assays. LEC migration was measured by Transwell and wound healing assays.Results: The mRNA levels of genes associated with cell proliferation, migration, epithelial-mesenchymal transition (EMT), TGF-β/BMP pathway and UPS, including Smurf1, were upregulated in ASC model. The mRNA expression of Smurf1 was also upregulated in anterior lens capsules of age-related cataract patients. Anterior chamber injection of A01 inhibited ASC formation and EMT. In vitro knockdown of Smurf1 resulted in reduced proliferation, TGF-β2-induced migration and EMT of LECs. Smurf1 inhibition upregulated Smad1, Smad5 and pSmad1/5. Conversely, Smurf1 overexpression displayed the opposite phenotypes.Conclusion: Smurf1 regulated the progression of fibrotic cataract by influencing the proliferation, migration and EMT of LECs through regulation of Smad signaling pathway, offering a novel target for the treatment of fibrotic cataract.
Project description:Purpose: TGF-β/BMP signaling pathway has a significant role in fibrotic cataract. Smurf1, a ubiquitin protein ligase, regulates the TGF-β/BMP signaling pathway through the ubiquitin-proteasome system (UPS). This study aims to investigate the role of Smurf1 in the progression of fibrotic cataract and its underlying mechanism.Method: We employed a mouse injury-induced anterior subcapsular cataract (ASC) model and administered Smurf1 inhibitor A01 through anterior chamber injection for in vivo investigation. RNA sequencing was performed to examine global gene expression changes. The volume of the subcapsular opacity was determined using whole-mount immunofluorescence of lens anterior capsules. Lentivirus was utilized to create cell lines with Smurf1 knockdown or overexpression in SRA01/04. Protein levels were assessed by Simple Western. Lens epithelial cell (LEC) proliferation was evaluated by CCK8 and EdU assays. LEC migration was measured by Transwell and wound healing assays.Results: The mRNA levels of genes associated with cell proliferation, migration, epithelial-mesenchymal transition (EMT), TGF-β/BMP pathway and UPS, including Smurf1, were upregulated in ASC model. The mRNA expression of Smurf1 was also upregulated in anterior lens capsules of age-related cataract patients. Anterior chamber injection of A01 inhibited ASC formation and EMT. In vitro knockdown of Smurf1 resulted in reduced proliferation, TGF-β2-induced migration and EMT of LECs. Smurf1 inhibition upregulated Smad1, Smad5 and pSmad1/5. Conversely, Smurf1 overexpression displayed the opposite phenotypes.Conclusion: Smurf1 regulated the progression of fibrotic cataract by influencing the proliferation, migration and EMT of LECs through regulation of Smad signaling pathway, offering a novel target for the treatment of fibrotic cataract.
Project description:Purpose: To better understand the effects of glutathione (GSH)-deficiency on lens homeostasis and cataractogenesis. Methods: The transcriptome of lens epithelia and fiber cells was obtained from C57BL/6 LEGSKO (lens GSH synthesis knockout) and buthionine sulfoximine (BSO)-treated LEGSKO mice and compared to C57BL/6 wild-type mice using RNA-Seq. Results: RNA-Seq results were in excellent agreement with qPCR (correlation coefficients between 0.87-0.94 and p<5E-6 for a subset of 36 mRNAs). Of the 24,415 transcripts mapped to the mouse genome, 441 genes showed significantly modulated expression. Pathway analysis indicated major changes in EMT signaling, visual cycle, small molecule biochemistry, and lipid metabolism. GSH-deficient lenses showed upregulation of genes relating to detoxification, including Aldh1a1, Aldh3a1 (aldehyde dehydrogenases), Mt1, Mt2 (metallothioneins), Ces1g (carboxylesterase), and Slc14a1 (urea transporter UT-B). These proteins share substrate specificity with GSH or glutathione-S-transferase and may protect GSH-deficient lenses. Genes associated with canonical EMT pathways, including Wnt10a, Egf, and Syk, showed upregulation in lens epithelia samples. Severely GSH-deficient lens epithelia showed a broad downregulation of vision-related genes (including Cryge, Crygf, and Rho). The BSO-treated LEGSKO lens epithelia transcriptome has significant correlation (r=0.63,P<0.005) to that of lens epithelia undergoing EMT. Conclusions: These results show that GSH depletion of the lens leads to expression of detoxifying genes and activation of EMT signaling, in addition to changes in transport systems and lipid homeostasis. These data give new insight into the adaptation and consequences of GSH-deficiency in the lens and suggest that supplementation of GSH or a precursor after cataract surgery could potentially reduce the incidence of EMT-mediated posterior subcapsular opacification.
Project description:Although majority of the genes linked to pediatric cataract exhibit lens fiber cell-enriched expression, our understanding of gene regulation in these cells is limited to function of just eight transcription factors and largely in the context of crystallins. Here, we identify small Maf transcription factors MafG and MafK as regulators of several non-crystallin human cataract genes in fiber cells and establish their significance to cataract. We applied a bioinformatics tool for cataract gene discovery iSyTE to identify MafG and its co-regulators in the lens, and generated various null-allelic combinations of MafG:MafK mouse mutants for phenotypic and molecular analysis. By age 4-months, MafG-/-:MafK+/- mutants exhibit lens defects that progressively develop into cataract. High-resolution phenotypic characterization of MafG-/-:MafK+/- lens reveals severe defects in fiber cells, while microarrays-based expression profiling identifies 97 differentially regulated genes (DRGs). Integrative analysis of MafG-/-:MafK+/- lens-DRGs with 1) binding-motifs and genomic targets of small Mafs and their regulatory partners, 2) iSyTE lens-expression data, and 3) interactions between DRGs in the String database, unravels a detailed small Maf regulatory network in the lens, several nodes of which are linked to human cataract. This analysis prioritizes 36 highly promising candidates from the original 97 DRGs. Significantly, 8/36 (22%) DRGs are associated with cataracts in human (GSTO1, MGST1, SC4MOL, UCHL1) or mouse (Aldh3a1, Crygf, Hspb1, Pcbd1), suggesting a multifactorial etiology that includes elevation of oxidative stress. These data identify MafG and MafK as new cataract-associated candidates and define their function in regulating largely non-crystallin genes linked to mouse and human cataract. Microarray comparision of lenses from mixed background (129Sv/J, C57BL/6J, and ICR) control (MafG+/-:MafK+/-; no-cataract) and compound (MafG-/-:MafK+/-; cataract) mouse mutants
Project description:This study investigates the response of human lens epithelial cells to mechanical injury. Human geriatric lenses obtained from cadaver eyes from donated to an eye bank for research were subject to in-vitro capsulotomy mimicking the injury sustained during cataract surgery. The anterior capsule was dissected using a curvilinear capsulorhexis technique, and central lens epithelial cells attached to the patch of anterior capsule (Rhexis) were immediately stabilized in RNAlater. The fiber cells were then removed, and the cortical fibers were immediately stabilized in RNA later. The remaining equatorial lens epithelial cells attached to the capsular bag from one eye were stabilized in RNA later immediately while the equatorial lens epithelial cells from the other eye were cultured for 24 hours then stabilized in RNAlater.
Project description:To explore the presence of extrachromosomal circular DNA (eccDNA) in the anterior capsule of the lens in the eyes of patients with cataract and with high myopia. Circle-Seq was performed to identify differences in the eccDNA and gene expression between the anterior capsule of the lens of patients with simple nuclear cataract (C, n = 6) and patients with nuclear cataract along with high myopia (HM, n = 6). The expression of eccDNA was confirmed using routine quantitative polymerase chain reaction. The eccDNA ranked in C and HM ranged in length from 0.017 kb – 9.9 Mb with two distinctive peaks detected at 0.2 kb and 0.5 kb, while eccDNA that were differentially expressed (up- and down-regulated) ranged in size from 0.05 kb – 57.8 kb with two distinctive peaks observed at 0.1 kb and 0.5 kb. Only 2.5 % of the eccDNA in C and 2 % in HM were > 25 kb in size. The gene-rich chromosomes contributed to more number of eccDNA/Mb, while several well-known high myopia candidate genes, including catenin delta 2 (CTNND2), ubiquitin-like with PHD and ring finger domains 1 binding protein 1 like (UHRF1BP1L) , exhibited significantly increased levels of eccDNA in the anterior capsule of the lens in patients with high myopia. This study highlighted the topologic analysis of the anterior capsule of eyes with high myopia, which is an emerging direction for research and clinical applications. These findings suggested that eccDNA was commonly detected in eyes with high myopia and cataracts, and the candidate genes for high myopia identified in previous studies were also observed in the eccDNA.
Project description:The Shumiya cataract rat (SCR) is a model for hereditary cataract. Two-third of these rats develop lens opacity within 10-11-weeks. Onset of cataract is attributed to the synergetic effect of lanosterol synthase (Lss) and farnesyl-diphosphate farnesyltransferase 1 (Fdft1) mutant alleles that lead to cholesterol deficiency in the lenses, which in turn adversely affects lens biology including the growth and differentiation of lens epithelial cells (LECs). Nevertheless, the molecular events and changes in gene expression associated with the onset of lens opacity in SCR is poorly understood. Our study aimed to identify the gene expression patterns during cataract formation in SCRs, which may be responsible for cataractogenesis in SCR.
Project description:The epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) has been proposed as a major cause of posterior capsule opacification (PCO) after cataract surgery. Molecular mechanism of PCO progression is still unclear. Using a microarray-based approach, herein we studied the changes in gene expression pattern during rat PCO formation in vivo as a model.