Panpan Ye

Hypoxia-induced deregulation of miR-126 and its regulative effect on VEGF and MMP-9 expression.

Objective: miR-126, the miRNA considered to be specially expressed in endothelial cells and hematopoietic progenitor cells, is strongly associated with angiogenesis. The purpose is to evaluate the role of miR-126 in hypoxia-induced angiogenesis and the possible mechanisms. Methods: The expression of miR-126 was detected in hypoxia-treated RF/6A cells and diabetic retinas using real-time PCR. The miR-126 was up- or down-regulated by transfecting miR-126-mimics or inhibitors into RF/6A cells. Cell cycle analysis was performed using flow cytometry. The protein levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) were assessed by immunoblotting. Results: A significantly decreased expression of miR-126 was found in hypoxia-treated RF/6A cells in a time-dependent manner compared with normoxic condition. The expression of miR-126 was also reduced in the retina tissue of streptozotocin-induced diabetic rats. The expression of VEGF and MMP-9 proteins was increased in hypoxia-induced RF/6A cells. In the functional analysis, miR-126-mimic significantly reduced the percentage of RF/6A cells in S phases compared with the negative control under hypoxic conditions. Furthermore, the VEGF and MMP-9 protein levels were sharply decreased in hypoxia-induced RF/6A cells pretreated with miR-126-mimics and increased in the cells pretreated with miR-126-inhibitors. Conclusions: miR-126 is down-regulated under hypoxic condition both in vitro and in vivo and may halt the hypoxia-induce neovascularization by suspending the cell cycle progression and inhibiting the expression of VEGF and MMP-9.

Effect of an intravitreal injection of bevacizumab on the expression of VEGF and CD34 in the retina of diabetic rats

Purpose:  To evaluate the efficacy of intravitreal injection of bevacizumab as a preventive intervention of vascular endothelial cell proliferation in the retina of diabetic rats.

Opticin production is reduced by hypoxia and VEGF in human retinal pigment epithelium via MMP-2 activation

Opticin, a small leucine rich repeat protein (SLRP) contributes to vitreoretinal adhesion. This study was conducted to investigate the effects of hypoxia and vascular endothelial growth factor (VEGF) on matrix metalloproteinase (MMP) mediated opticin production in retinal pigment epithelium (RPE) cells. Primary cultured human RPE cells were treated with hypoxia (low oxygen and cobalt chloride) or VEGF (0-100 ng/mL). The mRNA levels of opticin and the protein levels of intra and extracellular opticin in RPE cells were examined by RT-PCR and Western blot assay, respectively. Furthermore, the MMP activity was analyzed by zymography, and EDTA was used as an MMP inhibitor. Analysis of the effect of MMP-2 on opticin was performed by recombinant human (rh) MMP-2 stimulation in RPE cultures and by human vitreous sample digestion with activated rhMMP-2. Our results showed that opticin was expressed by primary cultured human RPE cells. Hypoxia and VEGF stimulation did not alter opticin mRNA and protein expression in RPE cells, but markedly decreased the protein levels of extracellular opticin following increased latent MMP-2 activity. The VEGF- and hypoxia induced opticin degradation in the culture medium was blocked by EDTA. Together, opticin levels in the culture medium were also reduced after rhMMP-2 treatment. In addition, opticin in human vitreous samples could be cleaved by rhMMP-2. These results reveal that VEGF and hypoxia could decrease opticin protein levels in the human RPE secretome, and that opticin may be an enzymatic substrate for MMP-2.

Conductive keratoplasty for symptomatic presbyopia following monofocal intraocular lens implantation

Background:  To evaluate the visual outcomes of conductive keratoplasty for relief of symptomatic presbyopia of pseudophakia with monofocal intraocular lens implantation.

Conductive keratoplasty for the treatment of astigmatism induced by corneal trauma or incision.

PURPOSE To assess the efficacy, safety, and predictability of conductive keratoplasty for the treatment of corneal trauma/incision-induced hyperopic or compound astigmatism. METHODS Thirteen eyes with corneal trauma/incision-induced astigmatism underwent conductive keratoplasty in this prospective study. The main outcome measures included distance uncorrected visual acuity (UCVA), near UCVA, best spectacle-corrected visual acuity (BSCVA), manifest refraction cylinder, keratometric astigmatism, manifest refraction spherical equivalent (MRSE), contrast sensitivity, glare sensitivity, intraocular pressure, tear break-up time, endothelial cell count, and pachymetry. Patients were followed 1 week and 1, 3, and 6 months postoperatively. RESULTS Mean logMAR scores for distance UCVA, near UCVA, and BSCVA significantly improved from 0.87+/-0.31, 1.32+/-0.41, and 0.18+/-0.18, respectively, to 0.32+/-0.21, 0.59+/-0.21, and 0.08+/-0.11 (P<or=.05), respectively, 6 months after conductive keratoplasty. Mean manifest refraction cylinder, keratometric astigmatism, and MRSE significantly reduced from 4.12+/-2.86 diopters (D), 4.15+/-2.40 D, and 0.73+/-2.56 D, respectively, to 1.46+/-1.35 D, 1.66+/-1.44 D, and -0.52+/-0.99 D (P<or=.05), respectively, at 6 months postoperatively. Contrast sensitivity and glare sensitivity showed significant improvement at spatial frequencies of 1, 1.6, 2.5, 4, and 6.3 cycles per degree (P<or=.05). Surgically induced astigmatism calculated by vector analysis highly correlated to target induced astigmatism (P<or=.05). No severe complications occurred postoperatively. CONCLUSIONS This study suggests that conductive keratoplasty is an effective and safe treatment for hyperopic or compound astigmatism after corneal trauma or incision.

Endostar inhibits hypoxia-induced cell proliferation and migration via the hypoxia-inducible factor-1α/vascular endothelial growth factor pathway in vitro.

Endostar, a recombinant human endostatin, is recognized as one of the most effective angiogenesis inhibitors. The angiogenesis inhibitory effects of Endostar suggest a possible beneficial role of Endostar in choroidal neovascularization (CNV), which is predominantly induced by hypoxia. In our previous study, it was reported that Endostar may inhibit the proliferation and migration of RF/6A choroid‑retinal endothelial cells. However, the inhibitory effect of Endostar on hypoxia‑induced cell proliferation and migration in RF/6A cells has not yet been elucidated. Therefore, the present study investigated the effect of Endostar on hypoxia‑induced cell proliferation and migration in RF/6A cells and the possible mechanisms underlying this effect. Under chemical hypoxia conditions, cell viability was increased to 114.9±10.1 and 123.6±9.6% in cells treated with 100 and 200 µm CoCl2, respectively, compared with the control (P<0.01). Pretreatment with 10‑100 µg/ml Endostar significantly inhibited CoCl2‑induced cell proliferation (P<0.05), and pre‑treatment with 10 µg/ml Endostar for 24, 48 and 96 h attenuated CoCl2‑promoted cell migration by 60.5, 48.3 and 39.6%, respectively, compared with the control (P<0.001). In addition, pretreatment with 10 µg/ml Endostar reversed the cell cycle arrest at S phase and the increased expression of hypoxia‑inducible factor‑1α (HIF‑1α) and vascular endothelial growth factor (VEGF) mRNA in RF/6A cells treated with 200 µM CoCl2. These data indicate that Endostar inhibited CoCl2‑induced hypoxic proliferation and migration, and limited cell cycle progression in vitro possibly through the HIF‑1α/VEGF pathway.

Epigallocatechin gallate regulates expression of apoptotic genes and protects cultured human lens epithelial cells under hyperglycemia

Abstract(-)-Epigallocatechin gallate (EGCG), the most abundant component in green tea, has a potent anti-apoptotic activity. The purpose of this study was to investigate the protective effects of EGCG and their molecular mechanisms on high glucose-induced apoptosis of human lens epithelial cells (HLEB-3). HLEB-3 cells were exposed to various concentrations of glucose and EGCG. Cell death was assessed by MTT assay and flow cytometry using annexin V and propidium iodide. The expression of the Bcl-2 family, c-fos, c-myc and p53 was measured by real-time PCR. EGCG decreased the Bcl-2/Bax expression stimulated by a high glucose. Moreover, EGCG suppressed the high glucose-induced expression of c-fos, c-myc and p53. These findings suggest that EGCG protects HLEB-3 cells from high glucose-induced apoptosis by regulating the gene expression of the Bcl-2 family, c-fos, c-myc and p53. Thus, EGCG may have a potential protective effect against diabetic cataract formation.

High glucose induces mitochondrial dysfunction and apoptosis in human retinal pigment epithelium cells via promoting SOCS1 and Fas/FasL signaling

Diabetic retinopathy (DR) is one of the most serious complications of diabetes mellitus (DM), however, the contribution of high glucose (HG) or hyperglycemia to DR is far from fully understanding. In the present study, we examined the expression of Fas/FasL signaling and suppressors of cytokine signaling (SOCS)1 and 3 in HG-induced human retinal pigment epithelium cells (ARPE-19 cells). And then we investigated the regulatory role of both Fas and SOCS1 in HG-induced mitochondrial dysfunction and apoptosis. Results demonstrated that HG with more than 40mM induced mitochondrial dysfunction via reducing mitochondrial membrane potential (MMP) and via inhibiting the Bcl-2 level, which is the upstream signaling of mitochondria in ARPE-19 cells. HG also upreuglated the Fas signaling and SOCS levels probably via promoting JAK/STAT signaling in ARPE-19 cells. Moreover, the exogenous Fas or entogenous overexpressed SOCS1 accentuated the HG-induced mitochondrial dysfunction and apoptosis, whereas the knockdown of either Fas or SOCS1 reduced the HG-induced mitochondria dysfunction and apoptosis. Thus, the present study confirmed that both Fas/FasL signaling and SOCS1 promoted the HG-induced mitochondrial dysfunction and apoptosis. These results implies the key regulatory role of Fas signaling and SOCS in DR.

Artisan iris-fixated intraocular lens implantation in combination with pupilloplasty—correction of aphakia with pathologically large pupil and insufficient capsular support

OBJECTIVE The aim of this study was to report the efficacy and safety of applying pupilloplasty in combination with Artisan iris-fixated intraocular lens (IOL) implantation in the treatment for aphakia with pathologically large pupil and insufficient capsular support. DESIGN The study was a retrospective case series. PARTICIPANTS Twenty-six aphakic eyes with pathologically large pupil and insufficient capsular support (from 26 patients) were included in the study. METHODS The study patients underwent pupilloplasty in combination with Artisan iris-fixated IOL implantation. Follow-up appointments were scheduled at 1 week and at 1, 3, and 6 months postoperatively. RESULTS The mean uncorrected visual acuity was significantly improved from logMAR 1.15 ± 0.29 to logMAR 0.37 ± 0.17, and the mean manifest refraction spherical equivalent was significantly decreased from 12.07 ± 2.20 D to -0.69 ± 0.70 D at 6 month after surgery (p < 0.05). The pupil diameter decreased significantly, from 5.7 ± 1.1 mm preoperatively to 4.5 ± 0.8 mm at 6 months after pupilloplasty (p < 0.05). Patients experienced less photophobia postoperatively. The safety parameters, including endothelial cell count, intraocular pressure, corneal astigmatism, best-corrected visual acuity, and central corneal thickness, showed no significant differences in values before and after surgery. CONCLUSIONS The Artisan iris-fixated IOL implantation in combination with pupilloplasty can be used as an alternative way to correct aphakia with pathologically large pupil and insufficient capsular support.

Ionizing radiation-induced microRNA expression changes in cultured RGC-5 cells.

MicroRNAs (miRNAs) are a class of short non-coding RNAs that regulate gene expression at the post-transcriptional level. It has been demonstrated that miRNAs serve a crucial role in tissue development and the pathogenesis of numerous diseases. The aim of the current study was to investigate the alterations in miRNA expression in a cultured retinal ganglion cell line (RGC-5 cells) following ionizing radiation injury. Cultured RGC-5 cells were exposed to X-rays at doses of 2, 4, 6 and 8 Gy using a medical linear accelerator. Alterations in cellular morphology were observed under a phase contrast microscope and cell viability was measured using the MTT assay. Subsequent to exposure to X-ray radiation for 5 days, the viability of RGC-5 cells was significantly reduced in the 6 and 8 Gy groups, accompanied by morphological alterations. Total RNA was then extracted from RGC-5 cells and subjected to miRNA microarray analysis subsequent to exposure to 6 Gy X-ray radiation for 5 days. The results of the microarray analysis indicated that the expression levels of 12 miRNAs were significantly different between the 6 Gy and control groups, including 6 upregulated miRNAs and 6 downregulated miRNAs. To verify microarray results, a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis was performed. The data obtained from RT-qPCR analysis was similar to that of the the microarray analysis for alterations in the expression of the 12 miRNAs. The results of the current study indicated that miRNA expression was sensitive to ionizing radiation, which may serve an important role in mechanisms of radiation injury in retinal ganglion cells.