BACKGROUNDRetinal degenerative diseases are the leading causes of blindness in developed world. Retinal progenitor cells (RPCs) play a key role in retina restoration. Triamcinolone acetonide (TA) is widely used for the treatment of retinal degenerative diseases. In this study, we investigated the role of TA on RPCs in hypoxia condition.

METHODSRPCs were primary cultured and identified by immunofluorescence staining. Cells were cultured under normoxia, hypoxia 6 h, and hypoxia 6 h with TA treatment conditions. For the TA treatment groups, after being cultured under hypoxia condition for 6 h, RPCs were treated with different concentrations of TA for 48-72 h. Cell viability was measured by cell counting kit-8 (CCK-8) assay. Cell cycle was detected by flow cytometry. Western blotting was employed to examine the expression of cyclin D1, Akt, p-Akt, nuclear factor (NF)-κB p65, and caspase-3.

RESULTSCCK-8 assays indicated that the viability of RPCs treated with 0.01 mg/ml TA in hypoxia group was improved after 48 h, comparing with control group (P < 0.05). After 72 h, the cell viability was enhanced in both 0.01 mg/ml and 0.02 mg/ml TA groups compared with control group (all P < 0.05). Flow cytometry revealed that there were more cells in S-phase in hypoxia 6 h group than in normoxia control group (P < 0.05). RPCs in S and G2/M phases decreased in groups given TA, comparing with other groups (all P < 0.05). There was no significant difference in the total Akt protein expression among different groups, whereas upregulation of p-Akt and NF-κB p65 protein expression and downregulation of caspase-3 and cyclin D1 protein expression were observed in 0.01 mg/ml TA group, comparing with hypoxia 6 h group and control group (all P < 0.05).

CONCLUSIONLow-dose TA has anti-apoptosis effect on RPCs while it has no stimulatory effect on cell proliferation.

Animals ; Apoptosis ; drug effects ; physiology ; Caspase 3 ; metabolism ; Cell Cycle ; drug effects ; physiology ; Cell Hypoxia ; drug effects ; physiology ; Cell Proliferation ; drug effects ; physiology ; Cell Survival ; drug effects ; physiology ; Cells, Cultured ; Cyclin D1 ; metabolism ; NF-kappa B ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retina ; cytology ; Stem Cells ; cytology ; drug effects ; Triamcinolone Acetonide ; pharmacology

OBJECTIVETo investigate the effect of MiR-200b on human retinal endothelial cells (hRECs) cultured in high glucose and explore the mechanism.

METHODShRECs cultured in high glucose or in normal media were examined for MiR-200b mRNA expression using real-time PCR. The effect of MiR-200b transfection on hREC proliferation in high-glucose culture was evaluated with MTT assay, and real-time PCR and Western blotting were performed to determine vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGFβ1) expression in the transfected cells.

RESULTSThe cells in high-glucose culture showed significantly decreased MiR-200b expression and active proliferation. Compared with those in normal control cells, VEGF and TGFβ1 mRNA and protein expressions increased markedly in cells cultured in high glucose (P<0.05). MiR-200b transfection of the cells caused significantly increased cellular expression of MiR-200b but decreased expression levels of VEGF and TGFβ1 mRNA and protein, and suppressed hREC proliferation in high glucose culture (P<0.05).

CONCLUSIONMiR-200b can regulate REC growth and proliferation by changing VEGF and TGFβ1 expressions and thus play a role in the pathogenesis and progression of diabetic retinopathy.

Blotting, Western ; Cell Proliferation ; Cells, Cultured ; Culture Media ; chemistry ; Diabetic Retinopathy ; Endothelial Cells ; cytology ; Glucose ; chemistry ; Humans ; MicroRNAs ; metabolism ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Retina ; cytology ; Transfection ; Transforming Growth Factor beta1 ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

Pax6 and its Drosophila homolog Eyeless (Ey) play essential roles during eye development. Ey/Pax6 contains two distinct DNA binding domains, a Paired domain (PD) and a Homeodomain (HD). While Ey/Pax6 PD is required for the expression of key regulators of retinal development, relatively little is known about the HD-dependent Ey function. In this study, we used the UAS/GAL4 system to determine the functions of different Ey domains on cell growth and on retinal development. We showed that Ey can promote cell growth, which requires the HD but not the PD. In contrast, the ability of Ey to activate Ato expression and induce ectopic eye formation requires the PD but not the HD. Interestingly, deletion of the HD enhanced Ey-dependent ectopic eye induction while overexpression of the HD only Ey forms antagonizes ectopic eye induction. These studies revealed a novel function of Ey HD on cell growth and a novel antagonistic effect of Ey HD on Ey PD-dependent eye induction. We further show the third helix of the Ey HD can directly interact with the RED subdomain in Ey PD and that deletion of the HD increased the binding of Ey PD to its target. These results suggest that the direct interaction between the HD and the PD potentially mediates their antagonistic effects. Since different Ey splicing forms are expressed in overlapping regions during normal development, we speculate that the expression ratios of the different Ey splice forms potentially contribute to the regulation of growth and differentiation of these tissues.
Animals ; Animals, Genetically Modified ; metabolism ; Binding Sites ; Cell Differentiation ; Cell Proliferation ; DNA-Binding Proteins ; metabolism ; Drosophila ; metabolism ; Drosophila Proteins ; antagonists & inhibitors ; metabolism ; Enhancer Elements, Genetic ; Eye Proteins ; antagonists & inhibitors ; metabolism ; Homeodomain Proteins ; antagonists & inhibitors ; metabolism ; PAX6 Transcription Factor ; Paired Box Transcription Factors ; antagonists & inhibitors ; metabolism ; Protein Structure, Tertiary ; Repressor Proteins ; antagonists & inhibitors ; metabolism ; Retina ; cytology ; metabolism ; Wings, Animal ; growth & development

The present study was undertaken to determine the effect of epigallocatechin gallate (EGCG) on lipopolysaccharide (LPS)-induced production of inflammatory chemokine regulated upon activation normal T cell expressed and secreted (RANTES) in human retinal endothelial cells (HRECs) and to explore the underlying regulatory mechanism. HRECs were stimulated with LPS in the presence or absence of EGCG at various concentrations (100, 50, 25, 12.5, 6.25 μmol/L). The optimum concentration of drug was determined by a real-time cell-electronic sensing (RT-CES) system, and MTS chromatometry was used to detect the toxicity of LPS and EGCG on HRECs. RANTES production in the culture supernatant was measured by ELISA. The expression levels of Akt and phosphorylated Akt were examined by Western blot assay. The result showed that LPS markedly stimulated RANTES secretion from HRECs. EGCG treatment significantly suppressed LPS-induced RANTES secretion in a dose-dependent manner. Furthermore, EGCG exhibited a dose-dependent inhibitory effect on LPS-induced phosphorylation of Akt. Taken together, our data suggest that EGCG suppresses LPS-induced RANTES secretion, possibly via inhibiting Akt phosphorylation in HRECs.
Catechin ; analogs & derivatives ; pharmacology ; Cells, Cultured ; Chemokine CCL5 ; metabolism ; Endothelial Cells ; metabolism ; Humans ; Lipopolysaccharides ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Retina ; cytology

BACKGROUNDDiabetes-related pathogenic factors can cause retinal ganglion cell (RGC) apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen synthase kinase-3 (GSK-3) activation and retinal neuron apoptosis.

METHODSIn an in vitro experiment, the number of apoptotic RGC-5 cells differentiated by staurosporine was evaluated via flow cytometry and nuclei staining using Hoechst 33258. GSK-3 phosphorylation and caspase-3 activation in RGC-5 cells after serum deprivation were determined using Western blotting. Mitochondrial membrane potential was detected using the dye 5, 5', 6, 6'tetrachloro-1, 1', 3, 3'-tetrethyl benzimidalyl carbocyanine iodide, and reactive oxygen species (ROS) levels were measured with dihydroethidium. In an in vivo experiment, the number of apoptotic retinal neurons was evaluated via terminal transferase dUTP nick-end labeling (TUNEL), and GSK-3 phosphorylation was determined using Western blotting, in the retinal nerve epithelial tissue of rats in which diabetes was induced by intravenous tail-vein injection of streptozotocin for 4 weeks.

RESULTSThe levels of phosphorylated Ser21/9 in GSK-3α/β and p-T308/S473-AKT were lower and the cleaved caspase-3 levels were higher in the serum-deprived model (P < 0.05). Lithium chloride treatment was associated with a slower rate of apoptosis, increased mitochondrial membrane potential, and decreased ROS levels in differentiated RGC-5 cells (P < 0.05). The level of blood glucose and the number of TUNEL-positive cells in the whole-mounted retinas were higher (P < 0.01), and the levels of phosphorylated Ser21/9 in GSK-3α/β and body weight were lower (P < 0.05). However, the thickness of the retinal nerve epithelial layer was not significantly less in diabetic rats compared with control group. Lithium chloride intravitreal injection increased the levels of phosphorylated Ser21/9 in GSK-3α/β and decreased TUNEL-positive cells in the whole-mounted retinas.

CONCLUSIONGSK-3 kinase is closely related to retinal neuron apoptosis, and the application of the GSK-3 inhibitor lithium chloride can reduce retinal neuron apoptosis in early diabetic retinopathy.

Animals ; Apoptosis ; genetics ; physiology ; Cell Line ; Cell Survival ; physiology ; Diabetic Retinopathy ; enzymology ; genetics ; metabolism ; Flow Cytometry ; Glycogen Synthase Kinase 3 ; genetics ; metabolism ; Male ; Neurons ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retina ; cytology ; enzymology

BACKGROUNDIn a previous study, we demonstrated that ephrin-A2 and -A3 negatively regulate the growth of neural progenitor cells in the central nervous system. Adult mice deficient in ephrin-A2 and -A3 (A2(-/-)A3(-/-)) displayed active ongoing neurogenesis throughout the brain, and mice deficient in ephrin-A3 alone showed increased proliferation of ciliary epithelium derived retinal stem cells. This study aimed to detect that the increase in proliferation and neurogenic potential of Müller cells is influenced by the absence of ephrin-A2 and -A3.

METHODSWe assessed the retinal and Müller cell expression of ephrin-As and their receptor and neural progenitor cell markers by immunostaining and real-time PCR. We cultured purified primary Müller cells derived from wild-type and A2(-/-)A3(-/-) mice in a defined culture medium that enables trans-differentiation of Müller cells into retinal neurons. To evaluate proliferating Müller cells in vivo, we injected 5'-ethylnyl-2'-deoxiuridine (EdU) intraperitoneally to adult mice.

RESULTSExpression of ephrin-A2/A3 and their receptor EphA4 were detected in the retinas of adult mice, with EphA4 expression particularly enriched in Müller cells. Müller cells of A2(-/-)A3(-/-) mice exhibited significantly elevated expression of retinal progenitor cell markers, Pax6 and Chx10, when compared with those from wild-type mice. Moreover, a higher percentage of Müller cells of A2(-/-)A3(-/-) mice trans-differentiated and became recoverin+ and β-III-tublin+ in the culture than those from wild type mice. Strikingly, an increased number of EdU+ retinal cells was detected in the retinas of adult A2(-/-)A3(-/-) mice as compared with wild-type mice.

CONCLUSIONSEphrin-A2 and -A3 are negative regulators of the proliferative and neurogenic potentials of Müller cells. Manipulating ephrin-A signaling may thus represent a novel strategy for stimulating neuroregeneration from endogenous progenitors to participate in retinal repair in case of disease or damage.

Animals ; Cell Differentiation ; genetics ; physiology ; Ephrin-A2 ; genetics ; metabolism ; Ephrin-A3 ; genetics ; metabolism ; Fluorescent Antibody Technique ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Real-Time Polymerase Chain Reaction ; Receptor, EphA4 ; genetics ; metabolism ; Retina ; cytology ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cells ; cytology ; metabolism

In the vertebrate retina, Müller cells are principal glial cells which stretch across the whole thickness of the retina and contact with the somata and processes of all retinal neurons, thus forming an anatomical and functional link between glial cells and retinal neurons. Numerous studies have shown that Müller cells express various neurotransmitter receptors, transporters, ion channels and enzymes that are relative to cellular activities. In addition, the cells also release factors, such as D-serine and glutamate etc., to regulate the neuron excitability. Therefore, retinal Müller cells may play more curious roles in addition to supporting the retinal neurons. The information exchange and interaction between Müller cells and neurons may regulate and maintain retinal neuronal functions. In the glaucomatous retina, Müller cells are reactivated (gliosis). Reactivated Müller cells undergo a variety of changes in cellular physiology, biochemistry and morphological features. Meanwhile, the reactivated Müller cells may produce and release cytotoxic factors, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS) and prostaglandin E2 (PGE2), thus involving in the induction of retinal ganglion cell apoptosis and death. Here, we reviewed the physiological properties of retinal Müller cells, and the functional changes of Müller cells in the glaucomatous retina.
Ependymoglial Cells ; pathology ; physiology ; Glaucoma ; physiopathology ; Humans ; Neurons ; physiology ; Retina ; cytology

The aim of the present study was to investigate the effects of prenatal alcohol exposure (PAE) on the development and cell differentiation of retina in offspring. The mouse model of PAE was made. HE staining and immunofluorescent labeling were carried out to visualize the structure, development and cell differentiation of the retina from postnatal day 0 (P0)-P30 offspring. The results showed that PAE can lead to the retardation of retinal development, the reduction of number of bipolar cells and horizontal cells, the disorder of horizontal cells' polarity, as well as the retinal thickening in a dose-dependent manner. The data suggest that alcohol exposure during pregnancy can lead to the developmental retardation of retina and decreased number of bipolar cells and horizontal cells in the retina of offspring.
Animals ; Cell Differentiation ; drug effects ; Disease Models, Animal ; Ethanol ; adverse effects ; Female ; Male ; Mice ; Pregnancy ; Prenatal Exposure Delayed Effects ; chemically induced ; Retina ; cytology ; drug effects ; Retinal Bipolar Cells ; drug effects ; Retinal Horizontal Cells ; drug effects

BrdU (5-Bromo-2'-deoxyuridine) is usually used to label the mitotic cells as well as to trace reagent in cell transplation. However, BrdU could also exert some side effect on cellular biological characteristics upon inappropriate use. To explore the appropriate concentration of BrdU for labelling retinal progenitor cells (RPCs), we co-cultured Embryonic day (E) 17. 5 RPCs with different concentrations of BrdU, which were 0.2, 1, 5 and 10 micromol/L, respectively. After 48 hours, the RPCs were proliferation- or differentiation-cultured. Immunofluorescence was used to detect the BrdU-positive ratio and differentiation potential. Cell count was used to evaluate proliferation ability, and lactate dehydrogenase (LDH) release assay was used to monitor cytotoxicity. The results showed that 0.2 micromol/ L BrdU could not label RPCs clearly, while BrdU of 1, 5 or 10 micromol/L could label the RPCs with similar ratios. 1 micromol/L BrdU displayed no obvious cytotoxicity and showed no obvious effect on the proliferation and differentiation ability. However, 5 micromol/L or 10 micromol/L BrdU could evidently inhibit RPCs proliferation, partly due to the cytotoxicity effect. Furthermore, 10 micromol/L BrdU could inhibit the differentiation of RPCs towards MAP2-positive nerve cells, but showed no influence on the differentiation of RPCs towards GFAP- and glutamine synthetase positive glial cells. This study suggested that 1 micromol/L BrdU could be an appropriate concentration for RPCs labelling and could efficiently label RPCs without obvious side effect.
Animals ; Bromodeoxyuridine ; chemistry ; Cell Culture Techniques ; methods ; Cell Differentiation ; Cell Proliferation ; Embryo, Mammalian ; Immunohistochemistry ; Mice ; Retina ; cytology ; Staining and Labeling ; Stem Cells ; cytology

One common feature of glaucoma, optic neuritis and some other optic nerve diseases is sustained and irreversible apoptosis of retinal ganglion cells (RGCs). Ginkgolide B is believed to protect neurons in brain and contribute to neurite outgrowth and synapse formation. The aim of the present study was to explore the effects of Ginkgo biloba extract (EGB761) and ginkgolide B on axonal growth of RCGs. Retina explants were cultured in three-dimensional tissue culture system, and the number and length of neurites were analyzed. Immunohistochemistry staining was performed to confirm that the neurite observed was axon of RGCs. TUNEL and activated caspase-3 staining were also applied to observe RGCs apoptosis. The result shows that neurites of RGCs treated with EGB761 or ginkgolide B were more and longer than those in control. The neurite is proved to be the axon of RGCs by immunostaining. Furthermore, compared with control group, RGCs treated with ginkgolide B showed decreased cellular apoptosis and inhibited caspase-3 activation. These results suggest ginkgolide B can promote RGCs axon growth by protecting RGCs against apoptosis.
Animals ; Apoptosis ; Axons ; drug effects ; Caspase 3 ; metabolism ; Ginkgolides ; pharmacology ; Lactones ; pharmacology ; Neurites ; drug effects ; Organ Culture Techniques ; Plant Extracts ; pharmacology ; Rats ; Retina ; Retinal Ganglion Cells ; cytology ; drug effects