Effect of bevacizumab (Avastin?) on mitochondrial function of in vitro retinal pigment epithelial,neurosensory retinal and microvascular endothelial cells

Purpose:

To evaluate the effect of bevacizumab on the mitochondrial function of human retinal pigment epithelial (ARPE-19), rat neurosensory retinal (R28) and human microvascular endothelial (HMVEC) cells in culture.

Materials and Methods:

ARPE-19 and R28 cells were treated with 0.125, 0.25, 0.50 and 1 mg/ml of bevacizumab. The HMVEC cultures were treated with 0.125, 0.25, 0.50 and 1 mg/ml of bevacizumab or 1 mg/ml of immunoglobulin G (control). Mitochondrial function assessed by mitochondrial dehydrogenase activity (MDA) was determined using the WST-1 assay.

Results:

Bevacizumab doses of 0.125 to 1 mg/ml for 5 days did not significantly affect the MDA of ARPE-19 cells. Bevacizumab treatment at 0.125 and 0.25 mg/ml (clinical dose) did not significantly affect the MDA of R28 cells; however, 0.50 and 1 mg/ml doses significantly reduced the R28 cell mitochondrial function. All doses of bevacizumab significantly reduced the MDA of proliferating and non-proliferating HMVEC.

Conclusion:

Bevacizumab exposure for 5 days was safe at clinical doses in both ARPE-19 and R28 retinal neurosensory cells in culture. By contrast, bevacizumab exposure at all doses show a significant dose-dependent decrease in mitochondrial activity in both the proliferating and non-proliferating HMVEC in vitro. This suggests a selective action of bevacizumab on endothelial cells at clinical doses.     

Toxicity of triamcinolone acetonide on retinal neurosensory and pigment epithelial cells

PURPOSE: To study the toxicity of triamcinolone acetonide (Kenalog; Bristol-Meyers Squibb, Princeton, NJ) on retinal pigment epithelial (ARPE-19) and retinal neurosensory (R28) cells. METHODS: ARPE-19 and R28 were grown in tissue culture in Dulbecco's modified Eagle's medium (DMEM) containing 10% fetal bovine serum. Cells were treated with 50, 100, and 200 microg/mL concentration of triamcinolone acetonide for 2, 6, and 24 hours. The cells were also treated with the steroid without the vehicle and with the vehicle alone, in which triamcinolone acetonide was suspended. Toxicity was determined by trypan blue dye-exclusion and WST-1 mitochondrial dehydrogenase assays. RESULTS: Vehicle alone did not reduce the viability of ARPE-19 or R28 cells and also did not affect the mitochondrial dehydrogenase activity of the cells. The mean cell viability of ARPE-19 and R28 cells after exposure to triamcinolone acetonide with vehicle 200 microg/mL for 24 hours was 70.7% +/- 10.61% and 75.35% +/- 12.42%, respectively compared with the untreated ARPE-19 (92.7% +/- 6.24%, P < 0.01) and R28 cells (90.63% +/- 5.62%, P < 0.001). The mean cell viability of ARPE-19 cells after exposure to triamcinolone acetonide (200 microg/mL) alone without the vehicle was 84.96% +/- 0.32%, 85.2% +/- 3.26%, and 84.73% +/- 2.71% at 2, 6, and 24 hours, respectively, compared with the untreated ARPE-19 cells (P < 0.001). The R28 cells exposed to triamcinolone acetonide (200 microg/mL) without the vehicle also had a significant reduction in the mean cell viability at 24 hours (86.42% +/- 3.87%, P < 0.001) and 6 hours (89.03% +/- 1.01%, P < 0.01). There was a significant reduction in the mitochondrial dehydrogenase activity in the ARPE-19 cells when treated with both triamcinolone acetonide, with or without the vehicle at a concentration of 200 microg/mL at all time points (P < 0.01). R28 cells did not have any significant reduction in mitochondrial dehydrogenase activity when treated with triamcinolone acetonide without the vehicle at any of the doses, but there was a significant reduction when the R28 cells were treated with triamcinolone acetonide with vehicle (200 microg/mL) for 24 hours (P < 0.05). Triamcinolone acetonide with vehicle caused a greater reduction in cell viability and mitochondrial dehydrogenase activity than did triamcinolone without vehicle, in both cell lines, although the difference was not statistically significant. CONCLUSIONS: Triamcinolone acetonide is toxic to proliferating cells of retinal origin in vitro at doses normally used in clinical practice. The vehicle by itself appears to be nontoxic to the cells, but may have a potentiating effect on the cytotoxicity of triamcinolone acetonide. The results of this in vitro study cannot be directly extrapolated to clinical practice, but, based on these data, further studies may be warranted.     

Trypan blue: effect on retinal pigment epithelial and neurosensory retinal cells

PURPOSE: To evaluate the toxicity of trypan blue on retinal cells in vitro. METHODS: Human retinal pigment epithelial cells (ARPE-19) and rat neurosensory retinal cells (R28) were grown in tissue culture and treated with four different concentrations of trypan blue (0.1%, 0.05%, 0.025%, and 0.0125%), in combination with surgical light exposure (0, 5, or 10 minutes). Cell viability, mitochondrial function, and DNA synthesis were measured by trypan blue dye-exclusion assay, mitochondrial dehydrogenase assay, and tritiated [3H] thymidine incorporation, respectively. RESULTS: ARPE-19 and R28 cells exposed to trypan blue with or without illumination did not show any significant decrease, either in cell viability by the dye-exclusion assay or in [3H] thymidine incorporation. R28 cells exposed to 0.1% trypan blue with and without light showed a significant reduction of mitochondrial dehydrogenase activity (P <0.05). ARPE-19 cells exposed to trypan blue, with or without light, did not show any significant decrease in mitochondrial dehydrogenase activity. CONCLUSIONS: This study suggests that rat neurosensory retina (R28) cells are more sensitive than human RPE (ARPE-19) cells to trypan blue. ARPE-19 cells showed no evidence of toxicity with any of the three assays, but R28 cells showed evidence of toxicity with the mitochondrial dehydrogenase assay at the higher doses and light-exposure times studied. Clinical studies must be conducted to determine the safety and efficacy of staining of the inner limiting membrane with trypan blue.     

贝伐单抗对体外培养的人视网膜色素上皮细胞增殖及纤维化的影响

目的：观察贝伐单抗对体外培养的人视网膜色素上皮细胞ARPE－19增殖及钙黏连蛋白（ E－cadherin ）和纤维连接蛋白（ fibronectin ）表达变化的作用,探讨贝伐单抗对ARPE－19增殖及纤维化的影响。方法：用不同浓度（0、0．625、1．25、2．5、5．0mg／mL）的贝伐单抗干预体外培养人视网膜色素上皮细胞ARPE－19,采用CCK－8法分别于24、48、72 h检测细胞活性;流式细胞仪检测细胞周期;应用免疫蛋白印迹法（ Western blotting）及逆转录聚合酶链反应（RT－PCR）检测ARPE－19中E－cadherin和fibronectin的蛋白及mRNA的表达变化。结果：浓度为2．5、5．0 mg／mL贝伐单抗能有效抑制ARPE－19细胞的增殖及细胞周期,差异有统计学意义（ P＜0.05）。2．5、5．0 mg／mL贝伐单抗能抑制E－cadherin 基因,促进fibronectin基因的转录及表达,差异有统计学意义（P＜0．05）。结论：高浓度的贝伐单抗能够抑制ARPE－19细胞的增殖,下调纤维化相关因子E－cadherin ,同时上调fibronectin的表达,提示高浓度的贝伐单抗可以引起ARPE－19细胞纤维化。     

Toxicity of indocyanine green (ICG) in combination with light on retinal pigment epithelial cells and neurosensory retinal cells

PURPOSE: To evaluate the toxicity of indocyanine green (ICG) in combination with light. METHODS: Human retinal pigment epithelial cells (ARPE-19) and rat neurosensory retinal cells (R28) were treated with four different concentrations of ICG in combination with light exposure. Cell viability, mitochondrial function, and DNA synthesis were measured. RESULTS: All concentrations of ICG with 10 min of light exposure caused a significant decrease in mitochondrial dehydrogenase activity in R28 and ARPE-19 cells. ICG without light exposure did not decrease mitochondrial dehydrogenase activity. In both cell lines, [(3)H]thymidine incorporation was increased when treated with ICG with or without light. R28 cells did not show any significant decrease in cell viability. CONCLUSIONS: The duration of light was a significant factor in ICG toxicity. ICG needs to be used with caution as it decreases the mitochondrial dehydrogenase activity and increases the DNA synthesis in retinal cells, markers for cell toxicity and dysfunction.     

Effects of hydroquinone on retinal and vascular cells in vitro

Aim:

To explore the molecular pathophysiology that might explain the epidemiologic association between cigarette smoke and age-related macular degeneration (AMD) by examining the effects of hydroquinone (HQ), a toxic compound present in high concentration in cigarette smoke-related tar, on human retinal pigment epithelial cells (ARPE-19), rat retinal neurosensory cells (R-28), and human microvascular endothelial cells (HMVEC).

Materials and Methods:

ARPE-19, R-28, and HMVEC were treated for 24 h with four different concentrations of HQ (500 μM, 200 μM, 100 μM, 50 μM). Cell viability, caspase-3/7 activation, DNA laddering patterns, and lactate dehydrogenase (LDH) levels were analyzed.

Results:

At 50 μM HQ, R-28 cells showed a significant decrease in cell viability compared with the dimethyl sulfoxide (DMSO)-treated controls. At the 100–500 μM concentrations, all three cell lines showed significant cell death (P < 0.001). In the ARPE-19, R-28, and HMVEC cultures, the caspase-3/7 activities were not increased at any of the HQ concentration.

Conclusion:

Our findings suggest that the mechanism of cell death in all three cell lines was through non-apoptotic pathway. In addition, neuroretinal R-28 cells were more sensitive to HQ than the ARPE-19 and HMVEC cultures.     

Hypothermia protects cultured human retinal pigment epithelial cells against indocyanine green toxicity.

PURPOSE: The aim of this study was to determine whether indocyanine green (ICG) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect the ARPE-19 cells against the ICG toxicity. METHODS: Cultured ARPE-19 cells were exposed to 0.25, 0.5, 1, 2.5, and 5 mg/mL of ICG dye at 37 and 4 degrees C for 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure. RESULTS: Exposure of the RPE cells to a hypotonic saline solution with an osmolarity equal to 5 mg/mL of ICG did not induce a statistically significant decrease in the percentage of RPE cells that survived. Exposure of the ARPE-19 cells to ICG induced a significant decrease in the percentage of cell survival at all concentrations of ICG (P<0.05), except in 0.25 mg/mL at 37 degrees C. At 4 degrees C, on the other hand, ICG induced a statistically significant decrease in the percentage of RPE cell survival only at 5 mg/mL of ICG (P<0.05). CONCLUSIONS: These results indicate that ICG is toxic to human RPE cells in culture, and that cell death cannot be attributed to the low osmolarity. Hypothermia of 4 degrees C has a protective effect against ICG toxicity.     

Bevacizumab modulates retinal pigment epithelial-to-mesenchymal transition via regulating Notch signaling

AIM: To investigate the effect of bevacizumab treatment on Notch signaling and the induction of epithelial-of-mesenchymal transition (EMT) in human retinal pigment epithelial cells (ARPE-19) in vitro. METHODS: In vitro cultivated ARPE-19 cells were treated with 0.25 mg/mL bevacizumab for 12, 24, and 48h. Cell morphology changes were observed under an inverted microscope. The expression of zonula occludens-1 (ZO-1), vimentin and Notch-1 intracellular domain (NICD) was examined by immunofluorescence. The mRNA levels of ZO-1, α-SMA, Notch-1, Notch-2, Notch-4, Dll4, Jagged-1, RBP-Jk and Hes-1 expression were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of α-SMA, NICD, Hes-1 and Dll-4 expression were examined with Western blot. RESULTS: Bevacizumab stimulation increased the expression of α-SMA and vimentin in ARPE-19 cells which changed into spindle-shaped fibroblast-like cells. Meanwhile, the mRNA expression of Hes-1 increased and the protein expression of Hes-1 and NICD also increased, which Notch signaling was activated. The mRNA expression of Notch-1, Jagged-1 and RBP-Jk increased at 48h, and while Dll4 mRNA and protein expression did not change after bevacizumab treatment. CONCLUSION: Jagged-1/Notch-1 signaling may play a critical role in bevacizumab-induced EMT in ARPE-19 cells, which provides a novel insight into the pathogenesis of intravitreal bevacizumab-associated complication.     

(R,R)-XY-10和(S,S)-XY-10诱导的视网膜色素上皮细胞增生作用及其作用机制(英文)

目的:观察(R, R)-XY-10和(S, S)-XY-10对视网膜色素上皮细胞的增生作用,并且进一步的研究其作用机制。但(R, R)-XY-10和(S, S)-XY-10对人脐静脉内皮细胞并无增生的作用。方法:通过人视网膜色素上皮细胞(ARPE-19)和人脐静脉内皮细胞(HUVECs)研究(R, R)-XY-10和(S, S)-XY-10对视网膜色素上皮细胞的增生作用,并且采用ERK、KT、PI3K、蛋白激酶C(PKC)和一氧化氮合酶(NOS)抑制剂来研究其作用机制。结果:(R, R)-XY-10和(S, S)-XY-10促进了ARPE-19细胞的增生,并具有剂量依赖性,但是对HUVECs细胞没有影响。如果同时加入增生抑制剂H7 (5μmol/L)、金丝桃素(20μmol/L)、PD98059(2μmol/L)、LY294002(50μmol/L)、SH-5(10μmol/L)和L-NAME (100μmol/L),则给予H7、金丝桃素、PD98059和LY294002各组的增生作用受到了抑制,而给予SH-5和L-NAME两组的增生作用没有影响。结论:(R, R)-XY-10和(S, S)-XY-10能够诱导ARPE-19细胞增生,其作用可能是通过MAPK和PI3K的途径来发挥该作用。因此,(R, R)-XY-10和(S, S)-XY-10能通过修复损伤的RPE细胞来治疗老年性黄斑变性。     

活性氧在贝伐单抗诱导视网膜色素上皮细胞上皮间质转化中的作用

目的　观察贝伐单抗（BEV）对人视网膜色素上皮（RPE）细胞氧化应激损伤和上皮间质转化（EMT）的影响,进一步探讨抑制活性氧（ROS）在EMT中的作用。方法　选取人ARPE-19细胞株,根据实验需要将ARPE-19细胞分为4组:空白对照组、BEV组、BEV+NAC组和BEV+DPI组,其中空白对照组细胞不进行任何干预,BEV组用0.25 g?L^-1 BEV处理细胞72 h,另外两组在 BEV处理细胞24 h后分别再用ROS抑制剂NAC和NADPH氧化酶抑制剂DPI处理细胞48 h。采用2,7-二氯二氢荧光素二乙酸酯（DCFH-DA）染色观察各组ARPE-19细胞内ROS和H₂O₂的生成堆积情况;细胞免疫荧光观察各组ARPE-19细胞中EMT标志物［紧密连接相关蛋白闭锁带蛋白-1（ZO-1）、α-平滑肌肌动蛋白（α-SMA）和纤维连接蛋白（FN）］的表达情况;再通过RT-PCR和Western blot检测各组细胞中EMT标志物的mRNA和蛋白的表达水平。结果　DCFH-DA染色观察发现,ARPE-19细胞加入BEV继续培养后,ROS和H₂O₂表达均明显上调（均为P＜0.05）。与空白对照组相比,BEV组EMT指标变化显著:上皮标志物ZO-1的表达降低,间质标志物α-SMA和FN的表达升高,两组间各指标相比差异均有统计学意义（均为P＜0.05）;与BEV组相比,BEV+NAC组和BEV+DPI组中各项指标mRNA表达变化显著,ZO-1上升至0.955±0.048、1.056±0.017,而α-SMA下降至0.982±0.165、1.058±0.165,此外FN表达（0.666±0.063、0.983±0.125）也显著降低,差异均有统计学意义（均为P＜0.05）。各种因子的蛋白表达变化趋势与其相应mRNA表达相一致,与单纯BEV组相比,ROS抑制剂NAC和NADPH氧化酶抑制剂DPI都显著改变了EMT标志物的表达,ZO-1蛋白相对表达量升高了0.195±0.010、0.770±0.175,而α-SMA下降了0.353±0.098、0.482±0.037,FN下降了0.528±0.161、0.612±0.134,差异均有统计学意义（均为P＜0.05）。结论　ROS参与了BEV诱导的RPE细胞EMT,抑制ROS可减轻BEV诱导的人RPE细胞的 EMT程度。     

曲安奈德对体外人视网膜色素上皮细胞增生的影响

目的 探讨曲安奈德（triamcinolone acetonide，TA）对人视网膜色素上皮细胞（human retinal pigment epithelium，ARPE-19）增生的影响。方法 采用MTT比色法测定终质量浓度为10、30、300mg／LTA分别作用于ARPE-19细胞24h和72h后的吸光度A值。结果 不同药物浓度TA对ARPE-19增殖的抑制作用差异有显著性（F0.05,3．16=3．24，P〈0．05）；此外，TA作用时间对ARPE-19增生的影响显著（F0.05 1,16=4．49，P〈0．05）；而且TA药物浓度和作用时间之间相互影响，对ARPE-19细胞增殖的抑制作用具有显著性意义（F0.04,1．16=4．49，P〈0．05）。结论 TA能够抑制视网膜色素上皮细胞的增殖，有望成为增殖性玻璃体视网膜病变的治疗药物。     

VEGF modulation of retinal pigment epithelium resistance

Fluid accumulation into the subretinal space and the development of macular edema is a common condition in age-related macular degeneration, diabetic retinopathy, and following ocular surgery, or injury. Vascular endothelial growth factor (VEGF) and other cytokines have been implicated in the disruption of retinal pigment epithelium (RPE) barrier function and a reduction in the regulated removal of subretinal fluid; however, the cellular and molecular events linking these agents to the disruption of barrier function have not been established. In the current study, cultures of ARPE-19 and primary porcine retinal pigment epithelium (RPE) cells were utilized to investigate the effects of the VEGF-induced modifications to the barrier properties of the RPE. The barrier function was determined by transepithelial resistance (TER) measurements and morphology of the RPE monolayers. In both ARPE-19 and primary porcine RPE cells the administration of VEGF produced a significant drop in TER, and this response was only observed following apical administration. Maximum reduction in TER was reached 5h post VEGF administration. These responses were concentration-dependent with an EC(50) of 502pg/mL in ARPE-19 cells and 251pg/mL in primary porcine cells. In both ARPE-19 and primary RPE cells, the response to VEGF was blocked by pretreatment with the relatively selective VEGF-R2 antagonists, SU5416 or ZM323881, or the protein tyrosine kinase inhibitor, genistein. Administration of the relatively selective VEGF-R2 agonist, VEGF-E, also reduced TER in a concentration-dependent manner (EC(50) of 474pg/mL), while VEGF-R1 agonist, placental growth factor (PlGF), did not significantly alter the TER. Immunolocalization studies demonstrated that confluent monolayers exhibited continuous cell-to-cell ZO-1 protein contacts and apical localization of the VEGF-R2 receptors. These data provide evidence that the VEGF-induced breakdown of RPE barrier function is mediated by the activation of apically-oriented VEGF-R2 receptors. Thus, VEGF-mediated increases in RPE permeability are initiated by a rise in intraocular levels of VEGF.     

Comparison of the in vitro toxicity of indocyanine green to that of trypan blue in human retinal pigment epithelium cell cultures

PURPOSE: To compare the in vitro toxicity of indocyanine green (ICG) to that of trypan blue (TB) in human retinal pigment epithelium cell cultures. The use of ICG and TB in macular hole surgery is discussed. DESIGN: In vitro cell biology experimental study. METHODS: The ICG dye and TB were applied to ARPE-19, a commercially available human retinal pigment epithelium cell line. Cultures were established and maintained according to supplier protocols. The ICG dye, TB or Hank's balanced salt solution (controls) were then applied to the cells at varying concentrations and over various exposure periods. Fiberoptic light was also applied to cells to assess for the possibility of a potentiating phototoxic effect. Cell viability fractions were determined using a well-studied mitochondrial dehydrogenase assay. RESULTS: The TB was not toxic to the retinal pigment epithelium cell cultures at any concentration or over any period of exposure, whereas ICG dye demonstrated dose-dependent and exposure-dependent toxicity. The ICG dye was found to be toxic to the cells at all tested concentrations between 5.0 mg/ml (stock concentration, 26.1% cell survival) and 0.5 mg/ml (92.8% cell survival) over a 3-minute exposure. No toxicity to TB was seen at the stock concentration of 1.5 mg/mL. Addition of light to the cultures did not significantly alter cell viability with either dye. Long periods of exposure, 2 hours, 24 hours, and 72 hours, to minute concentrations of either dye did not produce significant cell death. CONCLUSIONS: Indocyanine green demonstrates more toxicity than TB to human retinal pigment epithelium cell cultures. This is independent of any phototoxic potentiating effect of fiberoptic light or solvent toxicity. A clinically useful concentration of 0.5-mg/ml ICG causes low cytotoxicity at 3 minutes' exposure (cell survival 92.8%) and shows no detectable toxicity at 1-minute exposure (cell survival 102%).     

姜黄素通过抑制PI3K/Akt信号通路改善LPS诱导的视网膜炎症

目的:本研究旨在调查姜黄素是否能减轻动物模型和人视网膜色素上皮细胞(ARPE)-19细胞的视网膜炎症。方法:在体内,雄性C57/B6小鼠腹腔注射姜黄素3d,然后腹腔注射脂多糖(LPS;10mg/kg)诱导视网膜炎症。LPS作用24h后,通过RT-PCR检测促炎细胞因子的mRNA水平。伴刀豆球蛋白凝集素灌注标记技术评估了白细胞对视网膜脉管系统的粘附。用蛋白质定量试剂盒测量前房中的蛋白浓度。在体外,培养ARPE-19细胞。用细胞计数试剂盒8(CCK-8)法测量来选择姜黄素的最佳作用浓度。在用5μg/mL LPS刺激之前,将ARPE-19细胞在有或没有姜黄素的情况下孵育1h。通过RT-PCR和ELISA测量促炎细胞因子。通过蛋白质印迹分析PI3K/Akt表达。结果:姜黄素预处理可显著抑制EIU相关白细胞粘附于视网膜血管和前房蛋白渗漏。体内应用姜黄素后,炎症细胞因子(如IL-1β,IL-6和TNF-α)的mRNA表达水平也显著降低。同时,姜黄素在ARPE-19细胞的mRNA和蛋白质水平上均显著减弱IL-6,IL-8和MCP-1的表达。姜黄素抑制LPS激活的ARPE-19细胞中的PI3K/Akt磷酸化以及NF-κB激活。结论:姜黄素对LPS诱导的视网膜炎症具有预防作用,其作用似乎与PI3k/Akt信号传导途径的抑制有关。     

视网膜色素上皮细胞通过分泌含有miR-4488的外泌体抑制糖尿病视网膜病变进展的机制研究

目的　探讨视网膜色素上皮细胞通过分泌含有miR-4488的外泌体抑制糖尿病视网膜病变进展的分子机制。方法　将人视网膜色素上皮细胞系ARPE-19细胞分为空白组、高糖组。将人视网膜微血管内皮细胞（HRMECs）分为NG组、HG组、NG+外泌体组和HG+外泌体组。空白组、NG组和NG+外泌体组细胞用含5.5 mmol·L^-1正常浓度葡萄糖的培养基培养24 h;高糖组、HG组和HG+外泌体组细胞用含30 mmol·L^-1高浓度葡萄糖的培养基培养24 h;NG+外泌体组和HG+外泌体组细胞在培养基中分别加入空白组或高糖组ARPE-19细胞分泌的外泌体40 μg·L^-1。PKH67绿色荧光标记外泌体;利用CCK-8法、Transwell小室法检测HRMECs增殖、迁移和血管生成。取空白组和高糖组ARPE-19细胞外泌体进行miRNA微阵列分析。采用双荧光素酶报告分析检测miR-4488和转化生长因子β受体Ⅱ（TGFβR2）基因序列的靶向关系。采用Western blot或免疫荧光染色检测各组HRMECs中TGFβR2、Smad2、p-Smad2ser467或Desmin、α-平滑肌肌动蛋白（α-SMA）的表达。结果　空白组和高糖组ARPE-19细胞分泌的被PKH67标记的外泌体加入培养基后都可被HRMECs吸收。与NG组相比,HG组HRMECs细胞增殖率、迁移率、血管结点数和血管总长度、TGFβR2和p-Smad2ser467蛋白表达量、Desmin和α-SMA蛋白荧光强度均增加（均为P<0.05）;与HG组相比,HG+外泌体组上述指标均被逆转（均为P<0.05）;NG+外泌体组与NG组上述指标相比差异均无统计学意义（均为P>0.05）。与空白组相比,高糖组ARPE-19细胞分泌的外泌体中miR-4488相对表达量增加,且miR-4488模拟物和TGFβR2wt共转染可增加双荧光素酶活性（均为P<0.05）。结论　在高糖条件下,ARPE-19细胞释放的外泌体可通过miR-4488/TGFβR2/Smad信号通路抑制HRMECs间充质转化。     

玻璃膜疣主要成分胆固醇对人视网膜色素上皮细胞金属硫蛋白表达的影响

目的:研究玻璃膜疣主要成分胆固醇对人视网膜色素上皮细胞ARPE-19中金属硫蛋白表达的影响.方法:体外培养ARPE-19细胞,将细胞分为对照组和胆固醇处理组(2.5 mg/mL),取样时间为0,6,12,24,48,72 h.通过实时定量PCR检测hMT1a,hMT2a和hMT3在转录水平的表达,用蛋白质印迹法检测总金...     

Hydrogen peroxide-induced cell death in a human retinal pigment epithelial cell line,ARPE-19

The loss of retinal pigment epithelium (RPE) with aging is related to age-related macular degeneration (AMD). This study was conducted to investigate the mechanism of hydrogen peroxide (H2O2) induced cell death in a human retinal pigment epithelial cell line, ARPE-19. Hydrogen peroxide was added at different concentrations to ARPE-19 cells and cultured. The cytotoxicity was assayed by mitochondrial function using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. The patterns of cell damage were assessed using an acridine orange-ethidium bromide differential staining method, in situ end labeling (ISEL) assay and transmission electron microscopy (TEM). Catalase, a major antioxidant, was used to prevent cell death. The cleavage of procaspase 3 and poly (ADP-ribose) polymerase (PARP) was determined by western blot analysis. Hydrogen peroxide significantly induced cell death in ARPE-19 cells, whereas pretreatment of the cells with catalase prevented cell death. Application of the ISEL assay and acridine orange/ethidium bromide staining demonstrated that the H2O2-induced cell death occurred by an apoptotic mechanism at lower concentrations of H2O2 (400, 500, 600 microM), whereas higher concentrations of H2O2 induced necrosis rather than apoptosis. Caspase 3 was associated with the apoptotic pathway in human RPE cell death. Western blot analysis confirmed caspase 3 activation and cleavage of substrate proteins in ARPE-19 cells treated with an H2O2 concentration of 600 microM. These results indicate that treatment with H2O2 induces apoptotic and necrotic cell death in ARPE-19, and that caspase 3 is associated with apoptotic cell death. Therefore, H2O2 may induce the destruction of RPE cells in AMD by the combined effects of apoptosis and necrosis.     

Cadmium-induced apoptotic death of human retinal pigment epithelial cells is mediated by MAPK pathway

Cadmium (Cd), released from cigarette smoke and metal industrial activities, is known to accumulate in human body organs including retina and is particularly higher in retinal tissues of age-related macular degeneration (AMD) eyes compared to non-AMD eyes. We have determined the cytotoxic effects of Cd on human retinal pigment epithelial (RPE) cells. Upon Cd treatment, there was a dose- and time-dependent decline in ARPE-19 cell viability as well as early apoptotic changes such as altered mitochondrial membrane potential (MMP) and Cytochrome C release in cytosol. Depletion of GSH by buthionine-[S,R]-sulfoximine (BSO) resulted in increased Cd toxicity in ARPE-19 cells. Cadmium also caused reactive oxygen species (ROS) generation and activation of mitogen-activated protein kinases (MAPKs) pathway including c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (Erk1/2), and p38 in ARPE-19 cells. Antioxidants such as N-acetylcysteine (NAC) significantly reduced Cd-induced toxicity. These results indicate that elevated ROS-induced activation of the MAPK signaling pathway could be associated with Cd-induced RPE cell apoptosis, one of the major contributing factors in AMD. The toxic effects of Cd on ARPE-19 cells indicate that environmental heavy metals such as Cd could be important potential factors in RPE cells death associated retinal diseases particularly related to smoking.     

Activation of caspase-8 and caspase-12 pathways by 7-ketocholesterol in human retinal pigment epithelial cells

PURPOSE: To determine whether caspase or cathepsin pathways are activated in human retinal pigment epithelial cells (ARPE-19) after exposure to 7-ketocholesterol (7kCh). METHODS: ARPE-19 cells were exposed to 7kCh with or without z-VAD-fmk, a pan-caspase inhibitor. Caspase-3, -8, and -9 activities were measured by a fluorochrome inhibitor of caspase (FLICA) assay. Caspase-12 activity was detected by Western blotting. RT-PCR was performed for 18s, mortalin-2, cathepsins B, D, and L/V2. RESULTS: At 24 hours, 7kCh-treated cultures had increased caspase-8 (P < 0.001) and caspase-3 (P < 0.001) activities compared with vehicle-treated cultures. 7kCh-induced caspase-3 activation was blocked by z-VAD-fmk (P < 0.001). Caspase-9 was not activated by 7kCh treatment (P > 0.05). Procaspase-12 was cleaved into its active form after treatment with 7kCh for 24 hours. At 6 hours, the RNA level for mortalin-2, a pro-survival gene, was upregulated. ARPE-19 cells did not express RNA for cathepsins B, D, or L/V2 under any conditions. CONCLUSIONS: In ARPE-19 cells, 7kCh-induced apoptosis uses the receptor-mediated caspase-8 pathway and the endoplasmic reticulum stress-induced caspase-12 pathway but not the mitochondrial caspase-9 pathway. The cathepsin pathways are not involved in 7kCh-induced cell death. These data demonstrate that 7kCh causes a loss of cell viability through caspase-dependent apoptosis and can act as an oxidative stressor leading to retinal pigment epithelial cell atrophy. Elucidating the specific apoptotic pathways involved may have therapeutic potential for AMD and other retinal diseases.     

Antiproliferative and cytotoxic properties of bevacizumab on different ocular cells

AIM: To evaluate the antiproliferative and cytotoxic properties of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), on human retinal pigment epithelium (ARPE19) cells, rat retinal ganglion cells (RGC5), and pig choroidal endothelial cells (CEC). METHODS: Monolayer cultures of ARPE19, RGC5, and CEC were used. Bevacizumab (0.008-2.5 mg/ml), diluted in culture medium, was added to cells that were growing on cell culture dishes. Cellular proliferative activity was monitored by 5'-bromo-2'-deoxyuridine (BrdU) incorporation into cellular DNA and the morphology assessed microscopically. For cytotoxicity assays ARPE19, RGC5, and CEC cells were grown to confluence and then cultured in a serum depleted medium to ensure a static milieu. The MTT test was performed after 1 day. The "Live/Dead" viability/cytotoxicity assay was performed and analysed by fluorescence microscopy after 6, 12, 18, 24, 30, 36, and 48 hours of incubation. Expression of VEGF, VEGF receptors (VEGFR1 and VEGFR2) and von Willebrand factor was analysed by immunohistochemistry. RESULTS: No cytotoxicity of bevacizumab on RGC5, CEC, and ARPE19 cells could be observed after 1 day. However, after 2 days at a bevacizumab concentration of 2.5 mg/ml a moderate decrease in ARPE19 cell numbers and cell viability was observed. Bevacizumab caused a dose dependent suppression of DNA synthesis in CEC as a result of a moderate antiproliferative activity (maximum reduction 36.8%). No relevant antiproliferative effect of bevacizumab on RGC5 and ARPE19 cells could be observed when used at a concentration of 0.8 mg/ml or lower. CEC and ARPE 19 cells stained positively for VEGF, VEGFR1, and VEGFR2. More than 95% of the CEC were positive for von Willebrand factor. CONCLUSIONS: These experimental findings support the safety of intravitreal bevacizumab when used at the currently applied concentration of about 0.25 mg/ml. Bevacizumab exerts a moderate growth inhibition on CEC when used in concentrations of at least 0.025 mg/ml. However, at higher doses (2.5 mg/ml) bevacizumab may be harmful to the retinal pigment epithelium.