scholarly journals Bacillus cereus Induces Permeability of an In Vitro Blood-Retina Barrier

2008 ◽  
Vol 76 (4) ◽  
pp. 1358-1367 ◽  
Author(s):  
A. L. Moyer ◽  
R. T. Ramadan ◽  
J. Thurman ◽  
A. Burroughs ◽  
M. C. Callegan
Keyword(s):  
Quorum Sensing ◽  
Bacillus Cereus ◽  
Barrier Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Toxin Production ◽  
Global Regulator ◽  
Barrier Permeability ◽  
Cell Monolayers

ABSTRACT Most Bacillus cereus toxin production is controlled by the quorum-sensing-dependent, pleiotropic global regulator plcR, which contributes to the organism's virulence in the eye. The purpose of this study was to analyze the effects of B. cereus infection and plcR-regulated toxins on the barrier function of retinal pigment epithelium (RPE) cells, the primary cells of the blood-retina barrier. Human ARPE-19 cells were apically inoculated with wild-type or quorum-sensing-deficient B. cereus, and cytotoxicity was analyzed. plcR-regulated toxins were not required for B. cereus-induced RPE cytotoxicity, but these toxins did increase the rate of cell death, primarily by necrosis. B. cereus infection of polarized RPE cell monolayers resulted in increased barrier permeability, independent of plcR-regulated toxins. Loss of both occludin and ZO-1 expression occurred by 8 h postinfection, but alterations in tight junctions appeared to precede cytotoxicity. Of the several proinflammatory cytokines analyzed, only interleukin-6 was produced in response to B. cereus infection. These results demonstrate the deleterious effects of B. cereus infection on RPE barrier function and suggest that plcR-regulated toxins may not contribute significantly to RPE barrier permeability during infection.

scholarly journals Grape Seed Proanthocyanindin Extract Moderated Retinal Pigment Epithelium Cellular Senescence Through NAMPT/SIRT1/NLRP3 Pathway

2021 ◽  
Author(s):  
Yan Wu ◽  
Sanyou Dai ◽  
Yang Long ◽  
Hongzhuo Liu ◽  
Weiwei Wan ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Cellular Senescence ◽  
Barrier Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Grape Seed ◽  
Rpe Cells ◽  
Mitochondrial Homeostasis

Abstract Background: Cellular senescence of retinal pigment epithelium (RPE) cell was an important cause of degenerative retinal disorders, however, the potential effects of grape seed proanthocyanindin extract (GSPE) through regulating NAMPT/SIRT1/NLRP3 pathway remained unclear.Methods: The effects of GSPE on the cellular senescence biomarkers as well as NAMPT and NAD+ contents were detected in both in-vivo and in-vitro RPE cell models. The protection of GSPE treatment on the mitochondrial homeostasis and barrier function of RPE cells were detected with mtDNA lesions, JC-1 staining, ZO1 expression, trans-epithelial cell resistance (TEER) as well as senescence-associated secretory phenotype (SASP) expressions. The GSPE treatment with NAMPT inhibitor, Fk866, and SIRT1 inhibitor, EX-527, was used in the potential NAMPT/SIRT1/NLRP3 mechanism detection.Results: GSPE significantly improve the NAMPT and NAD+ content in aging mice and thus alleviated the RPE cellular senescence. In advanced in-vitro studies, GSPE could be an activator of NAMPT and thus relieved H2O2 induced NAD+ depression. In advanced analyses, it was reported that GSPE could alleviate mitochondrial homeostasis, barrier function and SASP of aging RPE cells. Thus, detection the SASP in in-vitro aging model provided us knowledge in the understanding of the anti-aging role of GSPE and following detailed pathological mechanism analyses demonstrated that GSPE demonstrated the protective effects in aging RPE cells through NAMPT/SIRT1/NLRP3 pathway.Conclusions: These findings indicate that GSPE alleviated cellular senescence both in-vivo and in-vitro through NAMPT/SIRT1/NLRP3 pathway. This study highlighted the importance both the potential GSPE in degenerative retinopathy as well as the crosstalk of NAD+ metabolism, SIRT1 function and NLRP3 activation.

scholarly journals Bestrophinopathies: perspectives on clinical disease, Bestrophin-1 function and developing therapies

2021 ◽  
Vol 13 ◽  
pp. 251584142199719
Author(s):  
Simranjeet Singh Grewal ◽  
Joseph J. Smith ◽  
Amanda-Jayne F. Carr
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Induced Pluripotent Stem Cell ◽  
Underlying Disease ◽  
Incomplete Penetrance ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
High Acuity ◽  
Induced Pluripotent

Bestrophinopathies are a group of clinically distinct inherited retinal dystrophies that typically affect the macular region, an area synonymous with central high acuity vision. This spectrum of disorders is caused by mutations in bestrophin1 ( BEST1), a protein thought to act as a Ca2+-activated Cl- channel in the retinal pigment epithelium (RPE) of the eye. Although bestrophinopathies are rare, over 250 individual pathological mutations have been identified in the BEST1 gene, with many reported to have various clinical expressivity and incomplete penetrance. With no current clinical treatments available for patients with bestrophinopathies, understanding the role of BEST1 in cells and the pathological pathways underlying disease has become a priority. Induced pluripotent stem cell (iPSC) technology is helping to uncover disease mechanisms and develop treatments for RPE diseases, like bestrophinopathies. Here, we provide a comprehensive review of the pathophysiology of bestrophinopathies and highlight how patient-derived iPSC-RPE are being used to test new genomic therapies in vitro.

scholarly journals Ocular Toxoplasmosis: Mechanisms of Retinal Infection and Experimental Models

Parasitologia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 50-60
Author(s):  
Veronica Rodriguez Fernandez ◽  
Giovanni Casini ◽  
Fabrizio Bruschi
Keyword(s):  
Ex Vivo ◽  
Cell Damage ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Treatment Strategies ◽  
Experimental Models ◽  
Ocular Toxoplasmosis ◽  
Cell Infection

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii and affects many individuals throughout the world. Infection may occur through congenital or acquired routes. The parasites enter the blood circulation and reach both the retina and the retinal pigment epithelium, where they may cause cell damage and cell death. Different routes of access are used by T. gondii to reach the retina through the retinal endothelium: by transmission inside leukocytes, as free parasites through a paracellular route, or after endothelial cell infection. A main feature of OT is the induction of an important inflammatory state, and the course of infection has been shown to be influenced by the host immunogenetics. On the other hand, there is evidence that the T. gondii phenotype also has an impact on the distribution of the pathology in different areas. Although considerable knowledge has been acquired on OT, a deeper knowledge of its mechanisms is necessary to provide new, more targeted treatment strategies. In particular, in addition to in vitro and in vivo experimental models, organotypic, ex vivo retinal explants may be useful in this direction.

Production of interleukin-6 by human retinal pigment epithelium in vitro and its regulation by other cytokines

1992 ◽  
Vol 11 (sup1) ◽  
pp. 173-179 ◽  
Author(s):  
Mark T. Benson ◽  
Lynda Shepherd ◽  
Robert C. Rees ◽  
Ian G. Rennie
Keyword(s):  
Retinal Pigment Epithelium ◽  
Interleukin 6 ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Human Retinal Pigment Epithelium

Maintenance of adult porcine retina and retinal pigment epithelium in perfusion culture: Characterisation of an organotypic in vitro model

2008 ◽  
Vol 86 (4) ◽  
pp. 661-668 ◽  
Author(s):  
Karin Kobuch ◽  
Wolfgang A. Herrmann ◽  
Carsten Framme ◽  
Helmut G. Sachs ◽  
Veit-Peter Gabel ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
In Vitro Model ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Perfusion Culture ◽  
Vitro Model

The cytoskeletal elements of human retinal pigment epithelium: in vitro and in vivo

1988 ◽  
Vol 91 (2) ◽  
pp. 303-312
Author(s):  
N.M. McKechnie ◽  
M. Boulton ◽  
H.L. Robey ◽  
F.J. Savage ◽  
I. Grierson
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cytokeratin 18 ◽  
Rpe Cells ◽  
Human Retinal Pigment Epithelium ◽  
Cytoskeletal Elements

The cytoskeletal elements of normal (in situ) and cultured human retinal pigment epithelium (RPE) were studied by a variety of immunocytochemical techniques. Primary antibodies to vimentin and cytokeratins were used. Positive immunoreactivity for vimentin was obtained with in situ and cultured material. The pattern of reactivity obtained with antisera and monoclonals to cytokeratins was more complex. Cytokeratin immunoreactivity could be demonstrated in situ and in cultured cells. The pattern of cytokeratin expression was similar to that of simple or glandular epithelia. A monoclonal antibody that specifically recognizes cytokeratin 18 identified a population of cultured RPE cells that had particularly well-defined filamentous networks within their cytoplasm. Freshly isolated RPE was cytokeratin 18 negative by immunofluorescence, but upon culture cytokeratin 18 positive cells were identifiable. Cytokeratin 18 positive cells were identified in all RPE cultures (other than early primaries), regardless of passage number, age or sex of the donor. In post-confluent cultures cytokeratin 18 cells were identified growing over cytokeratin 18 negative cells, suggesting an association of cytokeratin 18 immunoreactivity with cell proliferation. Immunofluorescence studies of retinal scar tissue from two individuals revealed the presence of numerous cytokeratin 18 positive cells. These findings indicate that RPE cells can be identified by their cytokeratin immunoreactivity and that the overt expression of cytokeratin 18 may be associated with proliferation of human RPE both in vitro and in vivo.

scholarly journals Human Na+-myo-inositol cotransporter gene: alternate splicing generates diverse transcripts

1998 ◽  
Vol 274 (5) ◽  
pp. C1215-C1225 ◽  
Author(s):  
Francesca Porcellati ◽  
Tommy Hlaing ◽  
Masaki Togawa ◽  
Martin J. Stevens ◽  
Dennis D. Larkin ◽  
...  
Keyword(s):  
Molecular Level ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Transcriptional Unit ◽  
Cdna Sequencing ◽  
Alternate Splicing ◽  
Reading Frame ◽  
Hypertonic Stress ◽  
Exon Splicing

Na+- myo-inositol cotransport activity generally maintains millimolar intracellular concentrations of myo-inositol and specifically promotes transepithelial myo-inositol transport in kidney, intestine, retina, and choroid plexus. Glucose-induced, tissue-specific myo-inositol depletion and impaired Na+- myo-inositol cotransport activity are implicated in the pathogenesis of diabetic complications, a process modeled in vitro in cultured human retinal pigment epithelium (RPE) cells. To explore this process at the molecular level, a human RPE cDNA library was screened with a canine Na+-dependent myo-inositol cotransporter (SMIT) cDNA. Overlapping cDNAs spanning 3569 nt were cloned. The resulting cDNA sequence contained a 2154-nt open reading frame, 97% identical to the canine SMIT amino acid sequence. Genomic clones containing SMIT exons suggested that the cDNA is derived from at least five exons. Hypertonic stress induced a time-dependent increase, initially in a 16-kb transcript and subsequently in 11.5-, 9.8-, 8.5-, 3.8-, and ∼1.2-kb SMIT transcripts, that was ascribed to alternate exon splicing using exon-specific probes and direct cDNA sequencing. The human SMIT gene is a complex multiexon transcriptional unit that by alternate exon splicing generates multiple SMIT transcripts that accumulate differentially in response to hypertonic stress.

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