The effects of mechanical strain on mouse eye lens capsule and cellular microstructure.
Ontology highlight
ABSTRACT:
SUBMITTER: Parreno J
PROVIDER: S-EPMC6232967 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Decorin (DCN) is involved in a variety of physiological and pathological processes. Epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) has been proposed as a major cause for the development of posterior capsule opacification (PCO) after cataract surgery. We investigated the plausible target gene(s) that suppress PCO. The expression of Dcn was significantly upregulated in rat PCO tissues compared to that observed in the control using a microarray-based approach. LECs treated with fibroblast growth factor (FGF) 2 displayed an enhanced level of DCN expression, while LECs treated with transforming growth factor (TGF)β-2 showed a decrease in DCN expression. The expression of tropomyosin 1 (Tpm1), a marker of lens EMT increased after the addition of TGFβ-2 in human LEC; however, upregulation of Tpm1 mRNA or protein expression was reduced in human LECs overexpressing human DCN (hDCN). No phenotypic changes were observed in the lenses of 8- and 48-week-old transgenic mice for lens-specific hDCN (hDCN-Tg). Injury-induced EMT of the mouse lens, and the expression patterns of α smooth muscle actin, were attenuated in hDCN-Tg mice lenses. Overexpression of DCN inhibited the TGFβ-2-induced upregulation of Tpm1 and EMT observed during wound healing of the lens, but it did not affect mouse lens morphology until 48 weeks of age. Our findings demonstrate that DCN plays a significant role in regulating EMT formation of LECs and PCO, and suggest that for therapeutic intervention, maintenance of physiological expression of DCN is essential to attenuate EMT progression and PCO formation.
| S-EPMC8070370 | biostudies-literature
Project description:The occurrence of a nuclear cataract in the eye lens due to disruption of the alpha3Cx46 connexin gene, Gja3, is dependent on strain background in a mouse model, implicating factors that modify the pathology. The differences upon cataractogenesis in the urea soluble proteins of the lens of two mouse strains, C57BL/6J and 129/SvJ, were analyzed by a comparative proteomics approach. Determination of the complete proteome of an organ offers the opportunity to characterize at a molecular level, differences in gene expression and PTMs occurring during pathology and between individuals. The abundance of 63 protein species was altered between the strains. A unique aspect of this study is the identification of chaperonin subunit 6A, mortalin, ERp29, and syntaxin-binding protein 6 in the eye lens. DNA polymorphisms resulting in nonconservative amino acid changes that led to altered physicochemical properties of the proteins were detected for mortalin, chaperonin subunit 6A, annexin A1, and possibly gamma-N crystallin. The results show HSP27/25 and/or ERp29 are the likely major modifying factors for cataractogenesis. Extension of the results suggests that small heat-shock proteins have a major role for influencing cataract formation in humans.
| S-EPMC3018240 | biostudies-literature
Project description:We assessed the importance of glycosaminoglycans and sulfur-mediated bonds for the mechanical properties of lens capsules by comparing the stress-strain responses from control and treated pairs of bovine source. No significant change in mechanical properties was observed upon reduction of disulfide bonds. However, removal of glycosaminoglycan chains resulted in a significantly stiffer lens capsule, whereas high concentrations of reducing agent, which is expected to reduce the recently reported sulfilimine bond of collagen IV, resulted in a significantly less stiff lens capsule. A comparison of the diffraction patterns of the control and strongly reduced lens capsules indicated structural rearrangements on a nanometer scale.
| S-EPMC3149272 | biostudies-literature
Project description:Congenital aniridia is caused by heterozygous mutations in the PAX6 gene. In this disease, congenital iris and foveal hypoplasia is associated with juvenile onset cataract, glaucoma, and corneal keratopathy. In rodents, Pax6 mutations result in a congenital reduction in ocular size that is not typically described in human aniridia. Here, the ocular morphometry of aniridia patients is compared with the lens phenotype of Pax6+/tm1/Pgr mice to reveal whether there are species differences in Pax6 regulation of lens development and homeostasis. Ultrasound biometry (UBM) revealed that eleven percent of aniridia patients exhibited mild microphthalmia while the anterior chamber depth of aniridic eyes was significantly reduced from 6 months of age onward. Although aniridic lens thickness was normal from birth, it was significantly decreased in aniridic lenses older than 30. Notably, 86% of aniridic lenses exhibited cataractous changes in this cohort. In addition, a significant proportion of aniridia patients develop lens subluxation as they age associated with reduced lens diameter as measured by anterior segment optical coherence tomography (AS-OCT). Analysis of young adult Pax6+/tm1/Pgr mouse lenses by micro-computed tomography (microCT), bright field and dark field imaging revealed that they are reduced in size but did not exhibit overt cataracts at this age. Overall, this study reveals that congenital microphthalmia as assessed by axial length, or microphakia, as assessed by lens thickness, are not typical in human aniridia, although these are primary manifestations of Pax6 mutations in mice, suggesting that PAX6 regulates some aspects of lens development differently between these species.
| S-EPMC7867623 | biostudies-literature
Project description:Eye lenses of various diurnal geckos contain up to 12% iota-crystallin. This protein is related to cellular retinol-binding protein type I (CRBP I) but has 3,4-didehydroretinol, rather than retinol, as a ligand. The 3,4-didehydroretinol gives the lens a yellow color, thus protecting the retina by absorbing short-wave radiation. iota-Crystallin could be either the gecko's housekeeping CRBP I, recruited for an additional function in the lens, or the specialized product of a duplicated CRBP I gene. The finding of the same CRBP I-like sequence in lens and liver cDNA of the gecko Lygodactylus picturatus now supports the former option. Comparison with iota-crystallin of a distantly related gecko, Gonatodes vittatus, and with mammalian CRBP I, suggests that acquiring the additional lens function is associated with increased amino acid changes. Compared with the rat CRBP I structure, the iota-crystallin model shows reduced negative surface charge, which might facilitate the required tight protein packing in the lens. Other changes may provide increased stability, advantageous for a long-living lens protein, without frustrating its role as retinol transporter outside the lens. Despite a number of replacements in the ligand pocket, recombinant iota-crystallin binds 3,4-didehydroretinol and retinol with similar and high affinity (approximately 1.6 nM). Availability of ligand thus determines whether it binds 3,4-didehydroretinol, as in the lens, or retinol, in other tissues. iota-Crystallin presents a striking example of exploiting the potential of an existing gene without prior duplication.
| S-EPMC16230 | biostudies-literature
Project description:The lens capsule compartmentalizes the cells of the avascular lens from other ocular tissues. Small molecules required for lens cell metabolism, such as glucose, salts, and waste products, freely pass through the capsule. However, the lens capsule is selectively permeable to proteins such as growth hormones and substrate carriers which are required for proper lens growth and development. We used fluorescence recovery after photobleaching (FRAP) to characterize the diffusional behavior of various sized dextrans (3, 10, 40, 150, and 250 kDa) and proteins endogenous to the lens environment (EGF, gammaD-crystallin, BSA, transferrin, ceruloplasmin, and IgG) within the capsules of whole living lenses. We found that proteins had dramatically different diffusion and partition coefficients as well as capsule matrix binding affinities than similar sized dextrans, but they had comparable permeabilities. We also found ionic interactions between proteins and the capsule matrix significantly influence permeability and binding affinity, while hydrophobic interactions had less of an effect. The removal of a single anionic residue from the surface of a protein, gammaD-crystallin [E107A], significantly altered its permeability and matrix binding affinity in the capsule. Our data indicated that permeabilities and binding affinities in the lens capsule varied between individual proteins and cannot be predicted by isoelectric points or molecular size alone.
| S-EPMC2849862 | biostudies-literature
Project description:The purpose of the study is to report the feasibility of implantation of a new design of anterior capsule-fixated intraocular lens (IOL). The new IOL design is a foldable, hydrophilic, open-loop posterior chamber IOL with two extra polymethyl methacrylate swivel haptics created on the optic surface to capture the anterior capsulotomy after the IOL is implanted in the bag. In the pilot phase, the new IOL was implanted in 10 eyes of 10 patients of which 8 eyes underwent phacoemulsification and 2 eyes had laser cataract surgery. The mean spherical equivalent changed from *1.75 D to -0.75 D at 6 months. Postoperatively, from 1 week to 6 months, all eyes showed stable refraction and anterior chamber depth with no evidence of decentration. Subjective questionnaire revealed high patient satisfaction with no complaints of dysphotopsia. No intra- or postoperative complications such as swivel haptic breakage, iris chafing, pigment dispersion, postoperative uveitis, or endophthalmitis occurred in any of the eyes necessitating explantation of the IOL. The new IOL design was feasible to implant and provided satisfactory outcomes in terms of no dysphotopsias and stable effective lens position.
| S-EPMC6113843 | biostudies-literature
Project description:Significantly altered cellular pathways in the transcriptomic profiling upon QKI depletion potentially play an important role in protein homeostasis in eye lens cells.
2021-02-14 | GSE145475 | GEO
Project description:PurposeThe dynamics of the posterior capsule during femtosecond laser lens fragmentation has received little attention in the literature. We analysed the movements of the posterior capsule to identify the rupture risk factors, if any, and to suggest possible modification of the laser spot energy pattern during fragmentation.Materials and methodsPosterior capsule ruptures during fragmentation were identified over a 10-year period of femtosecond laser use. In addition, the dynamics of the posterior capsule were identified through the real-time swept-source OCT lateral view available during the surgeries.ResultsOut of the 1465 laser cataract procedures performed, we recorded 1 case of posterior capsule rupture during lens fragmentation, which was caused by eye movement that was detected but ignored by the surgeon. Three types of posterior capsule dynamics were identified, all related to a gas bubble formation during the first part of the lens fragmentation. In eyes with a hard nucleus, the concussion of the posterior capsule was evident, however, with no capsule rupture.DiscussionMaintaining good docking throughout the whole procedure seems important in avoiding a posterior capsule cut by the femtosecond laser. In addition, a Gaussian pattern of spot energy is suggested when fragmenting hard cataracts.
| S-EPMC10400471 | biostudies-literature
Project description:MicroRNA expression in the mouse eye.MicroRNAs (miRNAs) are key regulators of biological processes. To define miRNA function in the eye, it is essential to determine a high-resolution profile of their spatial and temporal distribution. In this report, we present the first comprehensive survey of miRNA expression in ocular tissues, using both microarray and RNA in situ hybridization (ISH) procedures. We initially determined the expression profiles of miRNAs in the retina, lens, cornea and retinal pigment epithelium of the adult mouse eye by microarray. Each tissue exhibited notably distinct miRNA enrichment patterns and cluster analysis identified groups of miRNAs that showed predominant expression in specific ocular tissues or combinations of them. Next, we performed RNA ISH for over 220 miRNAs, including those showing the highest expression levels by microarray, and generated a high-resolution expression atlas of miRNAs in the developing and adult wild-type mouse eye, which is accessible in the form of a publicly available web database. We found that 122 miRNAs displayed restricted expression domains in the eye at different developmental stages, with the majority of them expressed in one or more cell layers of the neural retina . This analysis revealed miRNAs with differential expression in ocular tissues and provided a detailed atlas of their tissue-specific distribution during development of the murine eye. The combination of the two approaches offers a valuable resource to decipher the contributions of specific miRNAs and miRNA clusters to the development of distinct ocular structures.
2010-11-22 | GSE22882 | GEO