scholarly journals Visualising the membrane viscosity of porcine eye lens cells using molecular rotors

2017 ◽  
Vol 8 (5) ◽  
pp. 3523-3528 ◽  
Author(s):  
Peter S. Sherin ◽  
Ismael López-Duarte ◽  
Michael R. Dent ◽  
Markéta Kubánková ◽  
Aurimas Vyšniauskas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fluorescent Probes ◽  
Molecular Rotors ◽  
Eye Lens ◽  
Lens Fiber ◽  
Membrane Viscosity ◽  
Fiber Cells ◽  
Lens Cells ◽  
High Degree

Using fluorescent probes, we demonstrate that the plasma membrane of porcine eye lens fiber cells displays an unprecedentedly high degree of lipid ordering.

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.

scholarly journals Secreted frizzled-related protein disrupts PCP in eye lens fiber cells that have polarised primary cilia

2010 ◽  
Vol 338 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Yuki Sugiyama ◽  
Richard J.W. Stump ◽  
Anke Nguyen ◽  
Li Wen ◽  
Yongjuan Chen ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Eye Lens ◽  
Lens Fiber ◽  
Related Protein ◽  
Fiber Cells

scholarly journals Tropomyosin 3.5 protects F-actin networks required for tissue biomechanical properties

2018 ◽  
Author(s):  
Catherine Cheng ◽  
Roberta B. Nowak ◽  
Michael B. Amadeo ◽  
Sondip K. Biswas ◽  
Woo-Kuen Lo ◽  
...  
Keyword(s):  
Mechanical Load ◽  
Biomechanical Properties ◽  
Tissue Mechanics ◽  
Actin Binding ◽  
Eye Lens ◽  
Lens Fiber ◽  
Load Bearing ◽  
Actin Networks ◽  
Fiber Cells

AbstractTropomyosins (Tpms) stabilize F-actin and regulate interactions with other actin-binding proteins. The eye lens changes shape in order to fine focus light to transmit a clear image, and thus lens organ function is tied to its biomechanical properties, presenting an opportunity to study Tpm functions in tissue mechanics. The major mouse lens Tpm is Tpm3.5 (TM5NM5), a previously unstudied isoform. Decreased levels of Tpm3.5 lead to softer and less mechanically resilient lenses that are unable to resume their original shape after compression. While cell organization and morphology appear unaffected, Tmod1 dissociates from the membrane in Tpm3.5-deficient lens fiber cells resulting in reorganization of the spectrin-F-actin and α-actinin-F-actin networks at the membrane. These rearranged F-actin networks appear to be less able to support mechanical load and resilience leading to an overall change in tissue mechanical properties. This is the firstin vivoevidence that Tpm is essential for cell biomechanical stability in a load-bearing non-muscle tissue and indicates that Tpm3.5 protects mechanically stable, load-bearing F-actinin vivo.SummaryTropomyosin 3.5 stabilizes F-actin in eye lens fiber cells and promotes normal tissue biomechanical properties. Tpm3.5 deficiency leads to F-actin network rearrangements and decreased lens stiffness and resilience.

scholarly journals Structural and immunocytochemical alterations in eye lens fiber cells from Cx46 and Cx50 knockout mice

2006 ◽  
Vol 85 (8) ◽  
pp. 729-752 ◽  
Author(s):  
Irene Dunia ◽  
Christian Cibert ◽  
Xiaohua Gong ◽  
Chun-hong Xia ◽  
Michel Recouvreur ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Eye Lens ◽  
Lens Fiber ◽  
Fiber Cells

scholarly journals Eph-ephrin Signaling Affects Eye Lens Fiber Cell Intracellular Voltage and Membrane Conductance

2021 ◽  
Vol 12 ◽  
Author(s):  
Catherine Cheng ◽  
Junyuan Gao ◽  
Xiurong Sun ◽  
Richard T. Mathias
Keyword(s):  
Cell Membrane ◽  
Water Channel ◽  
Membrane Conductance ◽  
Building Blocks ◽  
Fiber Cell ◽  
Eye Lens ◽  
Lens Fiber ◽  
Fiber Cells ◽  
Lens Fibers ◽  
Lens Transparency

The avascular eye lens generates its own microcirculation that is required for maintaining lifelong lens transparency. The microcirculation relies on sodium ion flux, an extensive network of gap junction (GJ) plaques between lens fiber cells and transmembrane water channels. Disruption of connexin proteins, the building blocks of GJs, or aquaporins, which make up water and adhesion channels, lead to lens opacification or cataracts. Recent studies have revealed that disruption of Eph-ephrin signaling, in particular the receptor EphA2 and the ligand ephrin-A5, in humans and mice lead to congenital and age-related cataracts. We investigated whether changes in lens transparency in EphA2 or ephrin-A5 knockout (–/–) mice is related to changes in GJ coupling and lens fluid and ion homeostasis. Immunostaining revealed changes in connexin 50 (Cx50) subcellular localization in EphA2–/– peripheral lens fibers and alteration in aquaporin 0 (Aqp0) staining patterns in ephrin-A5–/– and EphA2–/– inner mature fiber cells. Surprisingly, there was no obvious change in GJ coupling in knockout lenses. However, there were changes in fiber cell membrane conductance and intracellular voltage in knockout lenses from 3-month-old mice. These knockout lenses displayed decreased conductance of mature fiber membranes and were hyperpolarized compared to control lenses. This is the first demonstration that the membrane conductance of lens fibers can be regulated. Together these data suggest that EphA2 may be needed for normal Cx50 localization to the cell membrane and that conductance of lens fiber cells requires normal Eph-ephrin signaling and water channel localization.

Developmental analysis of the eye lens obsolescence (Elo) gene in the mouse: cell proliferation and Elo gene expression in the aggregation chimera

Development ◽  
1991 ◽  
Vol 113 (4) ◽  
pp. 1293-1304 ◽  
Author(s):  
A. Yoshiki ◽  
M. Hanazono ◽  
S. Oda ◽  
N. Wakasugi ◽  
T. Sakakura ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cells ◽  
Cell Number ◽  
S Phase ◽  
Lens Epithelium ◽  
Posterior Region ◽  
Lens Epithelial Cells ◽  
Eye Lens ◽  
Lens Fiber ◽  
Fiber Cells

This study investigates the primary effect of the eye lens obsolescence (Elo) gene of the mouse. Morphological features of the Elo lens were defined as follows: (1) deficient elongation of lens fiber cells, (2) morphological abnormality of nuclei of lens fiber cells, (3) lack of eosinophilic granules in the central fiber cells and (4) rupture of lens capsule in the posterior region. We have immunohistologically examined, by means of an in vivo BrdU incorporation system, whether or not the Elo gene regulates cell proliferation during lens development. The lens fiber cells were morphologically abnormal in day 13 embryonic Elo lens. However, there were no significant differences in morphology or cell proliferation between normal and Elo lens epithelium until day 14 of gestation. After day 15, the total cell number in the Elo lens epithelium was significantly less than that in the normal, but the total numbers of S-phase cells in the two genotypes were not significantly different. The ratio of the total S-phase cell number to the total number of lens epithelial cells may be affected by the developmental stage, but not directly by the genotype. The genotype, however, may be having a direct influence at later ages because malformation of Elo lens fiber cells must cause reduction of the total number of lens epithelial cells in older embryos. Although, at 30 days old, Elo lens cells were externally extruded through the ruptured capsule into the vitreous cavity, BrdU-labelled lens epithelial cells were detectable. To investigate whether the Elo lens phenotype is determined by its own genotype or by its cellular environment, we produced aggregation chimeras between C3H-Elo/+(C/C) and BALB/c(c/c). Most lenses of BALB/c dominant chimeras were oval in shape without the ruptured lens capsule. However, they were opaque in the center and slightly smaller in size than normal. The lenses of C3H-Elo/+ dominant chimeras were morphologically similar to the Elo lens. Although normal nuclei were regularly arranged in the anterior region, Elo-type nuclei were located in the posterior region. Immunohistological staining by using anti-C3H strain-specific antibody demonstrated that the lens fiber cells with abnormal nuclei were derived only from C3H-Elo/+, not from BALB/c. These observations suggest that the primary effect of the Elo gene in the developing lens may be specific to the fiber cell differentiation rather than to the cell proliferation.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals A balance of FGF and BMP signals regulates cell cycle exit and Equarin expression in lens cells

2012 ◽  
Vol 23 (16) ◽  
pp. 3266-3274 ◽  
Author(s):  
Miguel Jarrin ◽  
Tanushree Pandit ◽  
Lena Gunhaga
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Lens Fiber ◽  
Cell Cycle Exit ◽  
Loss Of Function ◽  
Fiber Cells ◽  
Morphogenetic Protein ◽  
Lens Cells ◽  
Chick Lens

In embryonic and adult lenses, a balance of cell proliferation, cell cycle exit, and differentiation is necessary to maintain physical function. The molecular mechanisms regulating the transition of proliferating lens epithelial cells to differentiated primary lens fiber cells are poorly characterized. To investigate this question, we used gain- and loss-of-function analyses to modulate fibroblast growth factor (FGF) and/or bone morphogenetic protein (BMP) signals in chick lens/retina explants. Here we show that FGF activity plays a key role for proliferation independent of BMP signals. Moreover, a balance of FGF and BMP signals regulates cell cycle exit and the expression of Ccdc80 (also called Equarin), which is expressed at sites where differentiation of lens fiber cells occurs. BMP activity promotes cell cycle exit and induces Equarin expression in an FGF-dependent manner. In contrast, FGF activity is required but not sufficient to induce cell cycle exit or Equarin expression. Furthermore, our results show that in the absence of BMP activity, lens cells have increased cell cycle length or are arrested in the cell cycle, which leads to decreased cell cycle exit. Taken together, these findings suggest that proliferation, cell cycle exit, and early differentiation of primary lens fiber cells are regulated by counterbalancing BMP and FGF signals.

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