scholarly journals Control of lens epithelial cell survival.

1993 ◽  
Vol 121 (4) ◽  
pp. 899-908 ◽  
Author(s):  
Y Ishizaki ◽  
J T Voyvodic ◽  
J F Burne ◽  
M C Raff
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Lens Epithelial Cell ◽  
High Density ◽  
Lens Epithelial Cells ◽  
Cell Contact ◽  
Low Density ◽  
First Time ◽  
Cells Cultured ◽  
Do So

We have studied the survival requirements of developing lens epithelial cells to test the hypothesis that most cells are programmed to kill themselves unless they are continuously signaled by other cells not to do so. The lens cells survived for weeks in both explant cultures and high-density dissociated cell cultures in the absence of other cells or added serum or protein, suggesting that they do not require signals from other cell types to survive. When cultured at low density, however, they died by apoptosis, suggesting that they depend on other lens epithelial cells for their survival. Lens epithelial cells cultured at high density in agarose gels also survived for weeks, even though they were not in direct contact with one another, suggesting that they can promote one another's survival in the absence of cell-cell contact. Conditioned medium from high density cultures promoted the survival of cells cultured at low density, suggesting that lens epithelial cells support one another's survival by secreting survival factors. We show for the first time that normal cell death occurs within the anterior epithelium in the mature lens, but this death is strictly confined to the region of the anterior suture.

scholarly journals Autocrine signals enable chondrocytes to survive in culture.

1994 ◽  
Vol 126 (4) ◽  
pp. 1069-1077 ◽  
Author(s):  
Y Ishizaki ◽  
J F Burne ◽  
M C Raff
Keyword(s):  
Epithelial Cells ◽  
Cell Density ◽  
Mammalian Cells ◽  
Cell Types ◽  
High Density ◽  
Lens Epithelial Cells ◽  
Low Density ◽  
Cell Type ◽  
Adult Rats ◽  
And Cartilage

We recently proposed that most mammalian cells other than blastomeres may be programmed to kill themselves unless continuously signaled by other cells not to. Many observations indicate that some mammalian cells are programmed in this way, but is it the case for most mammalian cells? As it is impractical to test all of the hundreds of types of mammalian cells, we have focused on two tissues--lens and cartilage--which each contain only a single cell type: if there are cells that do not require signals from other cells to avoid programmed cell death (PCD), lens epithelial cells and cartilage cells (chondrocytes) might be expected to be among them. We have previously shown that rat lens epithelial cells can survive in serum-free culture without signals from other cell types but seem to require signals from other lens epithelial cells to survive: without such signals they undergo PCD. We show here that the same is true for rat (and chick) chondrocytes. They can survive for weeks in culture at high cell density in the absence of other cell types, serum, or exogenous proteins or signaling molecules, but they die with the morphological features of apoptosis in these conditions at low cell density. Medium from high density cultures, FCS, or a combination of known growth factors, all support prolonged chondrocyte survival in low density cultures, as long as antioxidants are also present. Moreover, medium from high density chondrocyte cultures promotes the survival of lens epithelial cells in low density cultures and vice versa. Chondrocytes isolated from adult rats behave similarly to those isolated from developing rats. These findings support the hypothesis that most mammalian cells require signals from other cells to avoid PCD, although the signals can sometimes be provided by cells of the same type, at least in tissues that contain only one cell type.

scholarly journals RhoA localization with caveolin-1 regulates vascular contractions to serotonin

2012 ◽  
Vol 303 (9) ◽  
pp. R959-R967 ◽  
Author(s):  
Daniel W. Nuno ◽  
Sarah K. England ◽  
Kathryn G. Lamping
Keyword(s):  
Lipid Rafts ◽  
Rho Kinase ◽  
Initial Response ◽  
Cell Types ◽  
Smooth Muscle Contraction ◽  
High Density ◽  
Low Density ◽  
Density Fractions ◽  
Caveolin 1 ◽  
Multiple Cell

Vascular smooth muscle contraction occurs following an initial response to an increase in intracellular calcium concentration and a sustained response following increases in the sensitivity of contractile proteins to calcium (calcium sensitization). This latter process is regulated by the rhoA/rho kinase pathway and activated by serotonin. In multiple cell types, signaling molecules compartmentalize within caveolae to regulate their activation. We hypothesized that serotonin differentially compartmentalizes rhoA within caveolar versus noncaveolar lipid rafts to regulate sustained vascular contractions. To test this hypothesis, we measured aortic contractions in response to serotonin in wild-type (WT) and cav-1-deficient mice (cav-1 KO). RhoA-dependent contractions in response to serotonin were markedly augmented in arteries from cav-1 KO mice despite a modest reduction in rhoA expression compared with WT. We found that under basal conditions, rhoA in WT arteries was primarily localized within high-density sucrose gradient fractions but temporally shifted to low-density fractions in response to serotonin. In contrast, rhoA in cav-1 KO arteries was primarily in low-density fractions and shifted to high-density fractions in a similar timeframe as that seen in WT mice. We conclude that localization of rhoA to caveolar versus noncaveolar lipid rafts differentially regulates its activation and contractions to rhoA-dependent agonists with greater activation associated with its localization to noncaveolar rafts. Disruption of rhoA localization within caveolae may contribute to increased activation and enhanced vascular contractions in cardiovascular disease.

scholarly journals Evidence for two physiologically distinct gap junctions expressed by the chick lens epithelial cell.

1986 ◽  
Vol 102 (1) ◽  
pp. 194-199 ◽  
Author(s):  
T M Miller ◽  
D A Goodenough
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Gap Junctions ◽  
Cell Communication ◽  
Cell Types ◽  
Lens Epithelial Cell ◽  
Dye Transfer ◽  
Fiber Cells ◽  
Junctional Permeability ◽  
Different Cell Types

Lens epithelial cells communicate with two different cell types. They communicate with other epithelial cells via gap junctions on their lateral membranes, and with fiber cells via junctions on their apices. We tested independently these two routes of cell-cell communication to determine if treatment with a 90% CO2-equilibrated medium caused a decrease in junctional permeability; the transfer of fluorescent dye was used as the assay. We found that the high-CO2 treatment blocked intraepithelial dye transfer but not fiber-to-epithelium dye transfer. The lens epithelial cell thus forms at least two physiologically distinct classes of gap junctions.

scholarly journals Faint Structures in Low Density Regions of the Nearby Universe

1999 ◽  
Vol 183 ◽  
pp. 256-256
Author(s):  
U. Lindner ◽  
K.J. Fricke ◽  
J. Einasto ◽  
M. Einasto
Keyword(s):  
Large Scale ◽  
Large Scale Structure ◽  
Morphological Type ◽  
High Density ◽  
Low Density ◽  
Clusters Of Galaxies ◽  
Galaxy Distribution ◽  
The Galaxy ◽  
Empty Sphere ◽  
First Time

We present an investigation of the galaxy distribution in the huge underdense region between the Hercules, Coma and Local Superclusters, the so-called Northern Local Void (NLV), using void statistics (for details refer to Lindner et al. this Volume). Reshift data for galaxies and poor clusters of galaxies are available in low and high density regions as well. Samples of galaxies with different morphological type and various luminosity limits have been studied separately and void catalogues have been compiled from three different luminosity limited galaxy samples for the first time. Voids have been found using the empty sphere method which has the potential to detect and describe subtle structures in the galaxy distribution. Our approach is complementary to most other methods usually used in Large–Scale Structure studies.

TAT-mediated PRDX6 protein transduction protects against eye lens epithelial cell death and delays lens opacity

2008 ◽  
Vol 294 (3) ◽  
pp. C842-C855 ◽  
Author(s):  
Eri Kubo ◽  
Nigar Fatma ◽  
Yoshio Akagi ◽  
David R. Beier ◽  
Sanjay P. Singh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Lens Epithelial Cell ◽  
Biologically Active ◽  
Lens Epithelial Cells ◽  
Protein Levels ◽  
Endogenous Antioxidant ◽  
Tgf Β1

A diminished level of endogenous antioxidant in cells/tissues is associated with reduced resistance to oxidative stress. Peroxiredoxin 6 (PRDX6), a protective molecule, regulates gene expression/function by controlling reactive oxygen species (ROS) levels. Using PRDX6 protein linked to TAT, the transduction domain from human immunodeficiency virus type 1 TAT protein, we demonstrated that PRDX6 was transduced into lens epithelial cells derived from rat or mouse lenses. The protein was biologically active, negatively regulating apoptosis and delaying progression of cataractogenesis by attenuating deleterious signaling. Lens epithelial cells from cataractous lenses bore elevated levels of ROS and were susceptible to oxidative stress. These cells harbored increased levels of active transforming growth factor (TGF)-β1 and of α-smooth muscle actin and βig-h3, markers for cataractogenesis. Importantly, cataractous lenses showed a 10-fold reduction in PRDX6 expression, whereas TGF-β1 mRNA and protein levels were elevated. The changes were reversed, and cataractogenesis was delayed when PRDX6 was supplied. Results suggest that delivery of PRDX6 can postpone cataractogenesis, and this should be an effective approach to delaying cataracts and other degenerative diseases that are associated with increased ROS.

Ultrastructure of the Celis of a Fish Tastebud

1976 ◽  
Vol 34 ◽  
pp. 128-129
Author(s):  
Gary E. Korte
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
B Cell ◽  
Cell Types ◽  
Afferent Nerve ◽  
The Other ◽  
Nerve Plexus ◽  
The Subject ◽  
First Time

Four types of specialized epithelial cells have been observed in the fish tastebud, within the capsule formed by the flattened epidermal cells. However, only two or three of these have been previously noted in any one species, including the glass catfish Kryptopterus bicirrhis, the subject of this investigation (1,2). For the first time, all four types of specialized cells have been observed,and an artifact of fixation relevant to the identification of these cell types has been uncovered.A single basal, or B cell lies on the basement membrane of the epidermis (Fig. 1). It makes many synapses with the afferent nerve plexus, which lies just above it. The other three cell types, designated S,L and T cells (Fig. 2A) are external to the nerve plexus, and only rarely make synapses onto nerves, confirming the observations of several other investigations.

Factors modulating mouse lens epithelial cell morphology with differentiation and development of a lentoid structure in vitro

Development ◽  
1987 ◽  
Vol 99 (1) ◽  
pp. 25-32
Author(s):  
A.L. Muggleton-Harris ◽  
N. Higbee
Keyword(s):  
Epithelial Cells ◽  
Collagen Gel ◽  
Cell Aggregation ◽  
Lens Epithelial Cell ◽  
Lens Capsule ◽  
Lens Epithelial Cells ◽  
Collagen Membrane ◽  
Mouse Lens

The morphological and cellular changes that occur with differentiation and development of a lentoid structure from cultured mouse lens epithelial cells have been found to be dependent on the presence of lens capsule in association with the cells. The development of the ‘lentoid body’ is a multiphase process involving cell replication, synthesis of mucosubstances and a basement collagen membrane, cell aggregation and differentiation. Stage-specific synthesis of lens proteins confirms that the genes regulating normal differentiation in vivo are operating in the in vitro system. The hydrated collagen gel studies described in this report demonstrate that the cuboidal morphology and apical-basal polarity of the lens epithelial cells are dependent on their relationship with the lens capsule. Following a replicative phase the cells assume a mesenchyme-like morphology and migrate into the gel. Trypsinized cells freed from the lens capsule replicate but form colonies on the surface of the gel. The implications of these results are discussed with respect to previous observations made on normal lens development and the abnormalities associated with the congenital cataractous embryonic lens.

scholarly journals Source-Dependent Intracellular Distribution of Iron in Lens Epithelial Cells Cultured Under Normoxic and Hypoxic Conditions

2013 ◽  
Vol 54 (12) ◽  
pp. 7666 ◽  
Author(s):  
Malgorzata Goralska ◽  
Steven Nagar ◽  
Lloyd N. Fleisher ◽  
Philip Mzyk ◽  
M. Christine McGahan
Keyword(s):  
Epithelial Cells ◽  
Intracellular Distribution ◽  
Lens Epithelial Cells ◽  
Hypoxic Conditions ◽  
Cells Cultured

scholarly journals Selective induction of tyrosine hydroxylase by cell-cell contact in bovine adrenal chromaffin cells is mimicked by plasma membranes.

1986 ◽  
Vol 103 (5) ◽  
pp. 1991-1997 ◽  
Author(s):  
S Saadat ◽  
H Thoenen
Keyword(s):  
Tyrosine Hydroxylase ◽  
Adrenal Medulla ◽  
Chromaffin Cells ◽  
Plasma Membranes ◽  
High Density ◽  
Heat Denaturation ◽  
Cell Contact ◽  
Low Density ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin

As a first step towards the identification and purification of the molecule(s) that are involved in cell contact-mediated tyrosine hydroxylase (TH) induction in cultures of bovine adrenal chromaffin cells, we have prepared plasma membranes (PM) from bovine adrenal medulla and tested their ability to mimick cell contact-mediated TH induction in low density chromaffin cultures. PM indeed induced TH in a manner similar to that observed in high density cultures. The maximal TH induction reached by PM corresponded to 69% of that of high density cultures, and half-maximal TH induction was obtained with 12 micrograms of PM per ml of medium. The induction of TH by PM was blocked by alpha-amanitin as observed in high density cultures. Since acetylcholinesterase was neither induced in high density nor in PM-treated low density cultures, an induction of TH as a result of a general increase in protein synthesis was excluded. The cell contact molecule(s) appear to be intrinsic membrane proteins. They were not removed by high or low salt extraction, but solubilized by 50 mM octylglucoside. They were resistant to 0.1% trypsin and heat denaturation but inactivated by 0.01% chymotrypsin. PM isolated from the adrenal cortex, kidney, and liver also induced TH in low density chromaffin cell cultures, although to a smaller extent than PM of the adrenal medulla. In contrast, muscle and erythrocyte PM were inactive. This shows that the cell contact molecule(s) are not restricted to the adrenal medulla, but are also present in some other but not all tissues.

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