scholarly journals Key Role for CRB2 in the Maintenance of Apicobasal Polarity in Retinal Pigment Epithelial Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Antonio E. Paniagua ◽  
Alicia Segurado ◽  
Jorge F. Dolón ◽  
Julián Esteve-Rudd ◽  
Almudena Velasco ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Retinal Pigment Epithelial ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelial Cells ◽  
Cell Junction ◽  
Subretinal Space ◽  
Rpe Cells ◽  
Pigment Epithelial ◽  
Apicobasal Polarity

Apicobasal polarity is essential for epithelial cell function, yet the roles of different proteins in its completion is not fully understood. Here, we have studied the role of the polarity protein, CRB2, in human retinal pigment epithelial (RPE) cells during polarization in vitro, and in mature murine RPE cells in vivo. After establishing a simplified protocol for the culture of human fetal RPE cells, we studied the temporal sequence of the expression and localization of polarity and cell junction proteins during polarization in these epithelial cells. We found that CRB2 plays a key role in tight junction maintenance as well as in cell cycle arrest. In addition, our studies in vivo show that the knockdown of CRB2 in the RPE affects to the distribution of different apical polarity proteins and results in perturbed retinal homeostasis, manifested by the invasion of activated microglial cells into the subretinal space. Together our results demonstrate that CRB2 is a key protein for the development and maintenance of a polarized epithelium.

Orientation of actin filaments in teleost retinal pigment epithelial cells, and the effect of the lectin, Concanavalin A, on melanosome motility

2014 ◽  
Vol 31 (1) ◽  
pp. 1-10 ◽  
Author(s):  
CHRISTINA KING-SMITH ◽  
RONALD J. VAGNOZZI ◽  
NICOLE E. FISCHER ◽  
PATRICK GANNON ◽  
SATYA GUNNAM
Keyword(s):  
Epithelial Cells ◽  
Actin Filament ◽  
Concanavalin A ◽  
Actin Filaments ◽  
Retinal Pigment Epithelial ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelial Cells ◽  
Rpe Cells ◽  
Pigment Epithelial ◽  
Pigment Epithelial Cells

AbstractRetinal pigment epithelial cells of teleosts contain numerous melanosomes (pigment granules) that exhibit light-dependent motility. In light, melanosomes disperse out of the retinal pigment epithelium (RPE) cell body (CB) into long apical projections that interdigitate with rod photoreceptors, thus shielding the photoreceptors from bleaching. In darkness, melanosomes aggregate through the apical projections back into the CB. Previous research has demonstrated that melanosome motility in the RPE CB requires microtubules, but in the RPE apical projections, actin filaments are necessary and sufficient for motility. We used myosin S1 labeling and platinum replica shadowing of dissociated RPE cells to determine actin filament polarity in apical projections. Actin filament bundles within RPE apical projections are uniformly oriented with barbed ends toward the distal tips. Treatment of RPE cells with the tetravalent lectin, Concanavalin A, which has been shown to suppress cortical actin flow by crosslinking of cell-surface proteins, inhibited melanosome aggregation and stimulated ectopic filopodia formation but did not block melanosome dispersion. The polarity orientation of F-actin in apical projections suggests that a barbed-end directed myosin motor could effect dispersion of melanosomes from the CB into apical projections. Inhibition of aggregation, but not dispersion, by ConA confirms that different actin-dependent mechanisms control these two processes and suggests that melanosome aggregation is sensitive to treatments previously shown to disrupt actin cortical flow.

Protection of Photoreceptor Cells from Phototoxicity by Transplanted Retinal Pigment Epithelial Cells Expressing Different Neurotrophic Factors

2005 ◽  
Vol 14 (10) ◽  
pp. 799-808 ◽  
Author(s):  
Toshiaki Abe ◽  
Yoko Saigo ◽  
Masayoshi Hojo ◽  
Tetsuya Kano ◽  
Ryosuke Wakusawa ◽  
...  
Keyword(s):  
Neurotrophic Factors ◽  
Retinal Pigment Epithelial ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Green Fluorescence Protein ◽  
Retinal Pigment Epithelial Cells ◽  
Subretinal Space ◽  
Egfp Gene ◽  
Rpe Cells ◽  
Pigment Epithelial

Transplantation of cells or tissues and the intravitreal injection of neurotrophic factors are two methods that have been used to treat retinal diseases. The purpose of this study was to examine the effects of combining both methods: the transplantation of retinal pigment epithelial (RPE) cells expressing different neurotrophic factors. The neutrophic factors were Axokine, brain derived-neurotrophic factor (BDNF), and basic fibroblast growth factor (bFGF). The enhanced green fluorescence protein (eGFP) gene was used as a reporter gene. These genes were transduced into RPE cells by lipofection, selected by antibiotics, and transplanted into the subretinal space of 108 rats. The rats were examined at 1 week and 3 months after the transplantation to determine whether the transduced cells were present, were expressing the protein, and were able to protect photoreceptors against phototoxicity. The survival of the transplanted cells was monitored by the presence of eGFP. The degree of protection was determined by the thickness of the outer nuclear layer. Our results showed that the degree of photoreceptor protection was different for the different types of neurotrophic factors at 1 week. After 3 months, the number of surviving transplanted cell was markedly reduced, and protection was observed only with the BDNF-transduced RPE cells. A significant degree of rescue was also observed by BDNF-transduced RPE cells in the nontransplanted area of the retina at both the early and late times. Lymphocytic infiltration was not detected in the vitreous, retina, and choroid at any time. We conclude that the transplantation of BDNF-transduced RPE cells can reduce the photoreceptor damage induced by phototoxicity in the transplanted area and weakly in the nontransplanted area.

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