scholarly journals Protein and Water Distribution Across Visual Axis in Mouse Lens: A Confocal Raman MicroSpectroscopic Study for Cold Cataract

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Li ◽  
Yuxing Li ◽  
Xi Liu ◽  
Yonghong He ◽  
Tian Guan
Keyword(s):  
Raman Spectra ◽  
Water Distribution ◽  
Lens Protein ◽  
Lens Fiber ◽  
Cataract Formation ◽  
Gaussian Peak ◽  
Lens Proteins ◽  
Fiber Cells ◽  
Different Temperatures ◽  
Mouse Lens

Purpose: The aims of the study were to investigate cellular mechanisms of cold cataract in young lenses of wild-type C57BL/6J (B6WT) mice treated at different temperatures and to test a hypothesis that cold cataract formation is associated with the changes in lens protein and water distribution at different regions across lens fiber cells by Raman spectroscopy (RS).Methods: RS was utilized to scan the mouse lens at different regions with/without cold cataract. Three regions with various opacification along the equatorial axis in the anterior–posterior lens section were scanned. The intensity ratio of Raman bands at 2,935 and 3,390 cm−1 (Ip/Iw) were used to evaluate lens protein and water distribution. We further determined water molecular changes through Gaussian profiles of water Raman spectra.Results: Three specific regions 1, 2, and 3, located at 790–809, 515–534, and 415–434 μm away from the lens center, of postnatal day 14 B6WT lenses, were subjected to RS analysis. At 37°C, all three regions were transparent. At 25°C, only region 3 became opaque, while at 4°C, both regions 2 and 3 showed opacity. The sum of the difference between Ip/Iw and the value of linear fitting line from scattered-line at each scanning point was considered as fluctuation degree (FD) in each region. Among different temperatures, opaque regions showed relatively higher FD values (0.63 and 0.79 for regions 2 and 3, respectively, at 4°C, and 0.53 for region 3 at 25°C), while transparent regions provided lower FD values (less than 0.27). In addition, the decrease in Gaussian peak II and the rising of Gaussian peak III and IV from water Raman spectra indicated the instability of water molecule structure in the regions with cold cataract.Conclusion: Fluctuation degrees of RS data reveal new mechanistic information about cold cataract formation, which is associated with uneven distribution of lens proteins and water across lens fiber cells. It is possible that RS data partly reveals cold temperature-induced redistribution of lens proteins such as intermediate filaments in inner fiber cells. This lens protein redistribution might be related to unstable structure of water molecules according to Gaussian profiles of water RS.

scholarly journals Disruption of the lens circulation causes calcium accumulation and precipitates in connexin mutant mice

2018 ◽  
Vol 314 (4) ◽  
pp. C492-C503 ◽  
Author(s):  
Junyuan Gao ◽  
Peter J. Minogue ◽  
Eric C. Beyer ◽  
Richard T. Mathias ◽  
Viviana M. Berthoud
Keyword(s):  
Autosomal Dominant ◽  
Circulation System ◽  
Lens Fiber ◽  
Cataract Formation ◽  
Wild Type ◽  
Mice Model ◽  
Internal Circulation ◽  
Alizarin Red ◽  
Fiber Cells ◽  
Junction Coupling

The lens is an avascular organ whose function and survival depend on an internal circulation system. Cx46fs380 mice model a human autosomal dominant cataract caused by a mutant lens connexin. In these mice, fiber cell connexin levels and gap junction coupling are severely decreased. The present studies were conducted to examine components of the lens circulation system that might be altered and contribute to the pathogenesis of cataracts. Lenses from wild-type mice and Cx46fs380 heterozygotes and homozygotes were studied at 2 months of age. Cx46fs380-expressing lens fiber cells were depolarized. Cx46fs380 lenses had increased intracellular hydrostatic pressure and concentrations of Na+ and Ca2+. The activity of epithelial Na+-K+-ATPase was decreased in Cx46fs380 lenses. All of these changes were more severe in homozygous than in heterozygous Cx46fs380 lenses. Cx46fs380 cataracts were stained by Alizarin red, a dye used to detect insoluble Ca2+. These data suggest that the lens internal circulation was disrupted by expression of Cx46fs380, leading to several consequences including accumulation of Ca2+ to levels so high that precipitates formed. Similar Ca2+-containing precipitates may contribute to cataract formation due to other genetic or acquired etiologies.

scholarly journals c-MAF deletion in adult C57BL/6J mice induces cataract formation and abnormal differentiation of lens fiber cells

2020 ◽  
Vol 69 (2) ◽  
pp. 242-249
Author(s):  
Mitsunori Fujino ◽  
Asuka Tagami ◽  
Masami Ojima ◽  
Seiya Mizuno ◽  
Ahmed M. Abdellatif ◽  
...  
Keyword(s):  
Lens Fiber ◽  
Cataract Formation ◽  
Fiber Cells

scholarly journals Ectopic Activation of Wnt/β-Catenin Signaling in Lens Fiber Cells Results in Cataract Formation and Aberrant Fiber Cell Differentiation

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e78279 ◽  
Author(s):  
Barbora Antosova ◽  
Jana Smolikova ◽  
Romana Borkovcova ◽  
Hynek Strnad ◽  
Jitka Lachova ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Fiber Cell ◽  
Lens Fiber ◽  
Cataract Formation ◽  
Fiber Cells ◽  
Ectopic Activation

Calmodulin-mediated gating of lens gap junction channels in vesicles

1984 ◽  
Vol 42 ◽  
pp. 134-137
Author(s):  
Camillo Peracchia ◽  
Stephen J. Girsch
Keyword(s):  
Gap Junctions ◽  
Freeze Fracture ◽  
Orthogonal Arrays ◽  
Eye Lens ◽  
Lens Fiber ◽  
Cell Coupling ◽  
Particle Spacing ◽  
Fiber Cells ◽  
Gap Junction Channels ◽  
Communicating Junctions

The fiber cells of eye lens communicate directly with each other by exchanging ions, dyes and metabolites. In most tissues this type of communication (cell coupling) is mediated by gap junctions. In the lens, the fiber cells are extensively interconnected by junctions. However, lens junctions, although morphologically similar to gap junctions, differ from them in a number of structural, biochemical and immunological features. Like gap junctions, lens junctions are regions of close cell-to-cell apposition. Unlike gap junctions, however, the extracellular gap is apparently absent in lens junctions, such that their thickness is approximately 2 nm smaller than that of typical gap junctions (Fig. 1,c). In freeze-fracture replicas, the particles of control lens junctions are more loosely packed than those of typical gap junctions (Fig. 1,a) and crystallize, when exposed to uncoupling agents such as Ca++, or H+, into pseudo-hexagonal, rhombic (Fig. 1,b) and orthogonal arrays with a particle-to-particle spacing of 6.5 nm. Because of these differences, questions have been raised about the interpretation of the lens junctions as communicating junctions, in spite of the fact that they are the only junctions interlinking lens fiber cells.

Contrasting patterns of c-myc and N-myc expression in proliferating, quiescent, and differentiating cells of the embryonic chicken lens

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 813-820
Author(s):  
L.L. Harris ◽  
J.C. Talian ◽  
P.S. Zelenka
Keyword(s):  
Cell Proliferation ◽  
Protein Product ◽  
Mrna Levels ◽  
Lens Fiber ◽  
Proliferating Cells ◽  
Fiber Cells ◽  
Embryonic Chicken ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation

The present study uses the polymerase chain reaction and in situ hybridization to examine c-myc and N-myc mRNA in the embryonic chicken lens at 6, 10, 14 and 19 days of development and compares the pattern of expression obtained with the developmental pattern of cell proliferation and differentiation. In the central epithelium, c-myc mRNA levels were proportional to the percentage of proliferating cells throughout development. N-myc mRNA expression in this region was relatively low and showed no correlation with cell proliferation. The ratio of N-myc to c-myc mRNA increased markedly with the onset of epithelial cell elongation and terminal fiber cell differentiation, although both c-myc and N-myc mRNAs continued to be expressed in postmitotic, elongating cells of the equatorial epithelium and in terminally differentiating lens fiber cells. Thus, increased expression of N-myc, a gene whose protein product may compete with c-myc protein for dimerization partners, accompanies the dissociation of c-myc expression and cell proliferation during terminal differentiation of lens fiber cells.

Cloning and functional expression of an MIP (AQP0) homolog from killifish (Fundulus heteroclitus) lens

2001 ◽  
Vol 281 (6) ◽  
pp. R1994-R2003 ◽  
Author(s):  
Leila V. Virkki ◽  
Gordon J. Cooper ◽  
Walter F. Boron
Keyword(s):  
Water Permeability ◽  
Fundulus Heteroclitus ◽  
Water Channel ◽  
Fold Increase ◽  
Functional Expression ◽  
Xenopus Laevis Oocytes ◽  
Lens Fiber ◽  
Fiber Cells ◽  
Aqp1 Expression ◽  
Very High

The major intrinsic protein (MIP) of lens fiber cells is a member of the aquaporin (AQP) water channel family. The protein is expressed at very high levels in lens fiber cells, but its physiological function is unclear. By homology to known AQPs, we have cloned a full-length cDNA encoding an MIP from the lens of killifish ( Fundulus heteroclitus). The predicted protein (263 amino acids; GenBank accession no. AF191906 ) shows 77% identity to amphibian MIPs, 70% identity to mammalian MIPs, and 46% identity to mammalian AQP1. Expression of MIPfun in Xenopus laevis oocytes causes an ∼40-fold increase in oocyte water permeability. This stimulation is comparable to that seen with AQP1 and substantially larger than that seen with other MIPs. The mercurials HgCl2 and p-chloromercuribenzenesulfonate inhibit the water permeability of MIPfun by ∼25%. MIPfun is not permeable to glycerol, urea, or formic acid but is weakly permeable to CO2.

scholarly journals The retinoblastoma protein-binding region of simian virus 40 large T antigen alters cell cycle regulation in lenses of transgenic mice.

1994 ◽  
Vol 14 (10) ◽  
pp. 6743-6754 ◽  
Author(s):  
L Fromm ◽  
W Shawlot ◽  
K Gunning ◽  
J S Butel ◽  
P A Overbeek
Keyword(s):  
Cell Cycle ◽  
Transgenic Mice ◽  
Retinoblastoma Protein ◽  
Simian Virus 40 ◽  
Cell Types ◽  
Simian Virus ◽  
T Antigen ◽  
Lens Fiber ◽  
Large T Antigen ◽  
Fiber Cells

Regulation of the cell cycle is a critical aspect of cellular proliferation, differentiation, and transformation. In many cell types, the differentiation process is accompanied by a loss of proliferative capability, so that terminally differentiated cells become postmitotic and no longer progress through the cell cycle. In the experiments described here, the ocular lens has been used as a system to examine the role of the retinoblastoma protein (pRb) family in regulation of the cell cycle during differentiation. The ocular lens is an ideal system for such studies, since it is composed of just two cell types: epithelial cells, which are capable of proliferation, and fiber cells, which are postmitotic. In order to inactivate pRb in viable mice, genes encoding either a truncated version of simian virus 40 large T antigen or the E7 protein of human papillomavirus were expressed in a lens-specific fashion in transgenic mice. Lens fiber cells in the transgenic mice were found to incorporate bromodeoxyuridine, implying inappropriate entry into the cell cycle. Surprisingly, the lens fiber cells did not proliferate as tumor cells but instead underwent programmed cell death, resulting in lens ablation and microphthalmia. Analogous lens alterations did not occur in mice expressing a modified version of the truncated T antigen that was mutated in the binding domain for the pRb family. These experimental results indicate that the retinoblastoma protein family plays a crucial role in blocking cell cycle progression and maintaining terminal differentiation in lens fiber cells. Apoptotic cell death ensues when fiber cells are induced to remain in or reenter the cell cycle.

The distribution of the fiber cell intrinsic membrane proteins MP20 and connexin46 in the bovine lens

1992 ◽  
Vol 103 (1) ◽  
pp. 245-257 ◽  
Author(s):  
E. Tenbroek ◽  
M. Arneson ◽  
L. Jarvis ◽  
C. Louis
Keyword(s):  
Monoclonal Antibody ◽  
Fiber Cell ◽  
Immunogold Electron Microscopy ◽  
Lens Fiber ◽  
Lens Fiber Cell ◽  
Western Blots ◽  
Fiber Cells ◽  
Bovine Lens ◽  
Narrow Side ◽  
Lens Membranes

MP20 is an intrinsic membrane protein previously identified in mammalian lens fiber cells. To identify a possible role for this protein in the lens, the distribution of MP20 and connexin46 has now been examined. Western immunoblotting with an anti-peptide antibody generated to the C-terminal 8 amino acids of MP20 confirmed the presence of this protein in the lens of several different mammalian species. A monoclonal antibody 5H1 was prepared that, in Western blots of bovine lesn membranes, recognized the same component as an antibody to rat connexin46 (Cx46). The apparent molecular mass of this component decreased from 59 kDa to 55 kDa following treatment of lens membranes with alkaline phosphatase. A monoclonal antibody to connexin-related MP70 recognized a 70 kDa component in bovine lens membranes confirming the presence of these two different connexin proteins in bovine lens membranes. To localize MP20 and Cx46 in the bovine lens membrane, lens fiber cell bundles were immunofluorescently labeled with both the MP20 antibody, and the monoclonal antibody to Cx46. Cx46 was identified in large plaques on the broad faces of the lens fiber cells throughout the outer 1 mm of the lens cortex. MP20 colocalized with Cx46 only in a restricted area 0.5 mm to 1.0 mm into the lens. In other regions of the lens, MP20 appeared more diffusely distributed over the fiber cell surface, although apparently concentrated in the ball-and-socket regions at the corners of the narrow side of the inner cortical lens fiber cells. These inner cortical regions were devoid of Cx46. A difference in distribution of these two proteins was confirmed in studies of immunofluorescently labeled lens cryosections. Furthermore, immunogold electron microscopy of purified lens membranes identified MP20 in both junctional regions (with Cx46) and in single membranes. These results provide evidence for a role for MP20 in mammalian lens fiber cell junctional formation or organization.

Membrane-binding properties of filensin, a cytoskeletal protein of the lens fiber cells

1992 ◽  
Vol 103 (3) ◽  
pp. 709-718 ◽  
Author(s):  
M. Brunkener ◽  
S.D. Georgatos
Keyword(s):  
Binding Capacity ◽  
Lens Fiber ◽  
Alkaline Ph ◽  
Trypsin Treatment ◽  
Binding Properties ◽  
Fiber Cells ◽  
Lens Membranes ◽  
Acylated Proteins ◽  
Triton X

Filensin is a 100/110 kDa membrane-associated protein found in lens fiber cells. Previous studies have shown that this protein polymerizes in vitro and binds strongly to vimentin and to another 47 kDa lens membrane protein. Using cosedimentation assays, flotation assays and immunoelectron microscopy, we have examined the properties of purified filensin and measured its binding to lens membranes. Filensin behaves as a ureaextractable, hydrophilic protein which does not partition with Triton X-114 and is not affected by 1 M hydroxylamine at alkaline pH, an agent known to release fatty-acylated proteins from the membrane. Immunoblotting of urea-extracted lens membranes with two different affinity-purified antibodies reveals that, unlike intact filensin, a COOH-terminal filensin degradation product (51 kDa) remains tightly associated with the membranes. Purified filensin binds directly to urea-stripped lens membranes, but not to protein-free vesicles reconstituted from total lens lipids. The binding of filensin is not significantly influenced by the purified 47 kDa protein. Interestingly, the filensin-binding capacity of urea-extracted membranes is increased at least two-fold after trypsin treatment, which removes entirely the 51 kDa peptide from the membranes and presumably unmasks additional filensin-acceptor sites. Consistent with this, filensin binds to trypsinized and non-trypsinized membranes with similar affinities (2 × 10(−7) and 4 × 10(−7) M, respectively). Treatment of the membranes with thrombin, which also eliminates the 51 kDa peptide, does not increase their binding capacity, apparently because filensin-acceptor sites are also destroyed during proteolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

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