Expression and significance of pigment epithelium-derived factor and vascular endothelial growth factor in colorectal adenoma and cancer

BACKGROUND The incidence and mortality of colorectal cancer(CRC)are among the highest in the world,and its occurrence and development are closely related to tumor neovascularization.When the balance between pigment epithelium-derived factors(PEDF)that inhibit angiogenesis and vascular endothelial growth factors(VEGF)that stimulate angiogenesis is broken,angiogenesis is out of control,resulting in tumor development.Therefore,it is very necessary to find more therapeutic targets for CRC for early intervention and later treatment.AIM To investigate the expression and significance of PEDF,VEGF,and CD31-stained microvessel density values(CD31-MVD)in normal colorectal mucosa,adenoma,and CRC.METHODS In this case-control study,we collected archived wax blocks of specimens from the Digestive Endoscopy Center and the General Surgery Department of Chengdu Second People's Hospital from April 2022 to October 2022.Fifty cases of specimen wax blocks were selected as normal intestinal mucosa confirmed by electronic colonoscopy and concurrent biopsy(normal control group),50 cases of specimen wax blocks were selected as colorectal adenoma confirmed by electronic colonoscopy and pathological biopsy(adenoma group),and 50 cases of specimen wax blocks were selected as CRC confirmed by postoperative pathological biopsy after inpatient operation of general surgery(CRC group).An immunohistochemical staining experiment was carried out to detect PEDF and VEGF expression in three groups of specimens,analyze their differences,study the relationship between the two and clinicopathological factors in CRC group,record CD31-MVD in the three groups,and analyze the correlation of PEDF,VEGF,and CD31-MVD in the colorectal adenoma group and the CRC group.The F test or adjusted F test is used to analyze measurement data statistically.Kruskal-Wallis rank sum test was used between groups for ranked data.The chi-square test,adjusted chi-square test,or Fisher's exact test were used to compare the rates between groups.All differences between groups were compared using the Bonferroni method for multiple comparisons.Spearman correlation analysis was used to test the correlation of the data.The test level(α)was 0.05,and a two-sided P<0.05 was considered statistically significant.RESULTS The positive expression rate and expression intensity of PEDF were gradually decreased in the normal control group,adenoma group,and CRC group(100%vs 78%vs 50%,χ^(2)=34.430,P<0.001;++~++vs+~++vs-~+,H=94.059,P<0.001),while VEGF increased gradually(0%vs 68%vs 96%,χ^(2)=98.35,P<0.001;-vs-~+vs++~+++,H=107.734,P<0.001).In the CRC group,the positive expression rate of PEDF decreased with the increase of differen-tiation degree,invasion depth,lymph node metastasis,distant metastasis,and TNM stage(χ^(2)=20.513,4.160,5.128,6.349,5.128,P<0.05);the high expression rate of VEGF was the opposite(χ^(2)=10.317,13.134,17.643,21.844,17.643,P<0.05).In the colorectal adenoma group,the expression intensity of PEDF correlated negatively with CD31-MVD(r=-0.601,P<0.001),whereas VEGF was not significantly different(r=0.258,P=0.07).In the CRC group,the expression intensity of PEDF correlated negatively with the expression intensity of CD31-MVD and VEGF(r=-0.297,P<0.05;r=-0.548,P<0.05),while VEGF expression intensity was positively related to CD31-MVD(r=0.421,P=0.002).CONCLUSION It is possible that PEDF can be used as a new treatment and prevention target for CRC by upregulating the expression of PEDF while inhibiting the expression of VEGF.

Expression of Pigment Epithelium-derived Factor in Bladder Tumour Is Correlated with Interleukin-8 yet Not with Interleukin-1α

Pigment epithelium-derived factor （PEDF） is an antiangiogenic factor which is effective in tumour inhibition in a variety of tumours and has not yet been studied in bladder tumour before. In this study the expression of PEDF, interleukin-1α （IL-1α） and -8 （IL-8） in bladder tumours was investigated. Immunohistochemistry was performed on 64 bladder tumour and 23 normal uroepithelium samples. Expression change of the factors was compared with clinicopathological parameters. Correlations between PEDF, IL-1α and IL-8 were analyzed. None of the factors was in relation to gender, tumour occurrence, and size or onset pattern. PEDF （P=0.014） and IL-1α （P=0.049） expression was down-regulated with grade progression. PEDF expression was lower in normal uroepithelium than in papillary urothelial neoplasm of low malignant potential （PUNLMP） （P=0.000） and carcinoma （P=0.009） whilst IL-1α （P=0.000 and P=0.000 respectively） and IL-8 （P=0.000 and P=0.023 respectively） expression was higher in the same grouping. PEDF expression had a negative correlation with IL-8 in PUNLMP （P=0.049, r=-0.578） as well as in tumour grouping （P=0.033, r=-0.276）. Deranged expressional change of PEDF, IL-1α and IL-8 could be in relation to loss of differentiation from normal uroepithelium to papillary lesion and eventually to carcinoma.

Pigment epithelium-derived factor protects retinal ganglion cells from hypoxia-induced apoptosis by preventing mitochondrial dysfunction

AIM： To investigate the potential of pigment epitheliumderived factor（PEDF） to protect the immortalized rat retinal ganglion cells-5（RGC-5） exposed to Co Cl2-induced chemical hypoxia. METHODS： After being differentiated with staurosporine（SS）, RGC-5 cells were cultured in four conditions： control group cells cultured in Dulbecco ＇s modified eagle medium（DMEM） supplemented with 10% fetal bovine serum, 100 μmol/m L streptomycin and penicillin（named as normal conditions）; hypoxia group cells cultured in DMEM containing 300 μmol/m L Co Cl2; cells in the group protected by PEDF were first pretreated with 100 ng/m L PEDF for 2h and then cultured in the same condition as hypoxia group cells; and PEDF group cells that were cultured in the presence of 100 ng/m L PEDF under normal conditions. The cell viability was assessed by MTT assay, the percentage of apoptotic cells was quantified using Annexin V-FITC apoptosis kit, and intra-cellar reactive oxygen species（ROS） was measured by dichloro-dihydro-fluorescein diacetate（DCFH-DA） probe. The mitochondria-mediated apoptosis was also examined to further study the underlying mechanism of the protective effect of PEDF. The opening of mitochondrial permeability transition pores（m PTPs） and membrane potential（Δψm） were tested as cellular adenosine triphosphate（ATP） level and glutathione（GSH）. Also, the expression and distribution of Cyt C and apoptosis inducing factor（AIF） were observed.RESULTS： SS induced differentiation of RGC-5 cells resulting in elongation of their neurites and establishing contacts between outgrowths. Exposure to 300 μmol/m L Co Cl2 triggered death of 30% of the total cells in cultures within 24 h. At the same time, pretreatment with 100 ng/m L PEDF significantly suppressed the cell death induced by hypoxia（P〈0.05）. The apoptosis induced by treatment of Co Cl2 was that induced cell death accompanied with increasing intracellar ROS and decreasing GSH and ATP level. PEDF pretreatment suppressed these effects（P〈0.05）. Additionally, PEDF treatment inhibited the opening of m PTPs and suppressed decreasing of Δψm in RGC-5 cells, resulting in blocking of the mitochondrial apoptotic pathway.CONCLUSION： Pretreatment of RGC-5 cells with 100 ng/m L PEDF significantly decreases the extent of apoptosis. PEDF inhibits the opening of m PTPs and suppresses decreasing of Δψm. Moreover, PEDF also reduces ROS production and inhibits cellular ATP level＇s reduction. Cyt C and AIF activation in PEDF-pretreated cultures are also reduced. These results demonstrate the potential for PEDF to protect RGCs against hypoxic damage in vitro by preventing mitochondrial dysfunction.

Potential therapeutic effects of pigment epithelium-derived factor for treatment of diabetic retinopathy

Diabetic retinopathy (DR), a major micro-vascular complication of diabetes, has emerged as a leading cause of visual impairment and blindness among working adults in the worldwide. The pathobiology of DR involves multiple molecular pathways and is characterized chronic neurovascular degeneration. Current approaches to prevent or to treat DR are still far from satisfactory. Therefore, it is important to develop new therapeutic strategies for the prevention and treatment to DR. Pigment epithelium-derived factor (PEDF), a 50-kDa secreted glycoprotein, has been described as a multi-functional protein. Some emerging evidences indicate that PEDF are able to target multiple pathways exerting neurotropic, neuroprotective, anti-angiogenic, antivasopermeability, anti-inflammation, anti-thrombogenic and anti-oxidative effects in DR. In this review, we addressed the functions of PEDF in different pathways, which could lead to potential therapeutics on the treatment to DR.

pigment epithelium-derived factor protects the morphological structure of retinal Müller cells in diabetic rats

AIM: To investigate if pigment epithelium-derived factor(PEDF) has any protective effect on the retinal Müller cells of Sprague-Dawley rats suffering from diabetes mellitus.METHODS: Sixty Sprague-Dawley rats were randomly divided into a negative control group, a group receiving0.1 μg/μL PEDF, another group receiving 0.2 μg/μL PEDF,and a group receiving balanced salt solution(BSS). Rats in both the PEDF and BSS groups were treated intravitreally based on previously established diabetic models. After 4wk of treatment, morphological alterations of Müller cells and protein expression of glutamine synthase(GS) and glial fibrillary acidic protein(GFAP)were analyzed.RESULTS:PEDFateither0.1μg/μLor0.2μg/μLsignificantly improved the structures of both nuclei and organelles of Müller cells compared to the BSS-treated group.Expression of GS was significantly higher in the 0.2 μg/μL PEDF group than that in the BSS group(P =0.012), but expression of GFAP was significantly lower in the 0.2 μg/μL PEDF group than that in the BSS group(P =0.000);however, there were no significant differences in expression of these proteins between the 0.1 μg/μL PEDF group and the BSS group(P =0.608, P =0.152). CONCLUSION: PEDF protects the morphological ultrastructure of Müller cells, improves the expression of glutamate synthase and prevents cell gliosis.

Study of Pigment Epithelium-derived Factor in Pathogenesis of Diabetic Retinopathy

Diabetic retinopathy(DR), a major micro-vascular complication of diabetes, has emerged as a leading cause of visual impairment and blindness among adults worldwide. However,aside from pathological damage, the traditional laser and multi-needle operation treatments required for more advanced disease can cause further damage to the visual field and increase the operation risk. Therefore, the development of new therapeutic strategies for the prevention and treatment of DR is essential..Some emerging evidence now indicates that pigment epithelium-derived factor(PEDF), a multifunctional protein,can target multiple pathways to exert neurotropic,.neuroprotective, anti-angiogenic, anti-vasopermeability, anti-inflammation, anti-thrombogenic, and anti-oxidative effects against DR. This review addresses the functions of PEDF in different pathways that could lead to potential therapeutics for the treatment of DR.

Pigment Epithelium-derived Factor in Cataractous Aqueous Humor and Lens Epithelial Cells

Purpose: To study the characteristics of PEDF in cataractous aqueous humor and its expression in human lens epithelium. Methods: The PEDF concentration in the aqueous humor was measured by enzyme -linked immunosorbent assay in senile (130cases) and congenital (18cases) cataract patients who underwent cataract phacoemulsification extraction surgery. Anterior lens capsular specimens were obtained from these patients to count lens epithelial cells (LEC) density. The Lens Opacities Classification System Ⅲ was used to classify the senile cataracts as cortical, nuclear, posterior subcapsular and mixed types of opacity, and quantitative analysis of the nuclear opacities was performed by Pentacam Scheimpflug imaging system. Anterior lens capsular specimens from another senile (10cases) and congenital (10cases) cataract were collected for immunofluorescence with polyclonal antibodies specific to human pigment epithelium -derived factor (PEDF). Results:The mean aqueous level of PEDF was(178. 9±87. 5)ng/ml, and there was negative linear correlation of PEDF level and age (r=0. 811, P<0. 001). In senile cases, the aqueous PEDF concentration decreased with increasing nuclear opacities (r=0. 447, P < 0.01) , and the mean PEDF level in nuclear cataract was significantly lower than that in posterior subcapsular opacity (P < 0.01) . PEDF immunostaining was detected in LEC of all capsular specimens. Conclusion : The PEDF level in human aqueous humor is related to age, types of cataracts and lens opacity. PEDF also express in human LEC. The study results suggest PEDF may regulate and/or protect LEC by paracrine and autocrine, and lack of PEDF may play a role in cataractogenesis.

Effect of local injection of pigment epithelium-derived factor on angiogenesis, inflammatory response and apoptosis in the retina of diabetic rats

Objective: To study the effect of local injection of pigment epithelium-derived factor (PEDF) on angiogenesis, inflammatory response and apoptosis in the retina of diabetic rats. Methods:Adult male SD rats were selected as experimental animals and randomly divided into control group, DM group and PEDF group, DM group and PEDF group were made into diabetes models through intraperitoneal injection of streptozotocin, and PEDF group were given local injection of PEDF. The contents of angiogenesis molecules and inflammatory response molecules as well as the expression of apoptosis genes in retinal tissue were measured after intervention. Results: mTOR, VEGF, VEGFR, Ang-2, Tie-2, NF-κB, COX2, iNOS, SDF-1 and CXCR4 contents as well as ASK1, JNK, p38MAPK and Caspase-3 mRNA expression in retinal tissue of DM group were significantly higher than those of control group whereas Survivin and Bcl-2 mRNA expression were significantly lower than those of control group;mTOR, VEGF, VEGFR, Ang-2, Tie-2, NF-κB, COX2, iNOS, SDF-1 and CXCR4 contents as well as ASK1, JNK, p38MAPK and Caspase-3 mRNA expression in retinal tissue of PEDF group were significantly lower than those of DM group whereas Survivin and Bcl-2 mRNA expression were significantly higher than those of control group. Conclusion: Local injection of PEDF has inhibitory effect on the angiogenesis, inflammatory response and apoptosis in the retina of diabetic rats.

Ultrasound-mediated microbubble delivery of pigment epithelium-derived factor gene into retina inhibits choroidal neovascularization

Background Many studies have suggested that the imbalance of angiogenic factor and anti-angiogenic factor expression contributes significantly to the development of choroidal neovascularization （CNV）, and ultrasound microbubble combination system can increase the gene transfection efficiency successfully. This study was designed to investigate whether ultrasound-mediated microbubble destruction could effectively deliver therapeutic plasmid into the retina of rat, and whether gene transfer of pigment epithelium-derived factor （PEDF） could inhibit CNV.Methods Human retinal pigment epithelial cells were isolated and treated either with ultrasound or plasmid alone, or with a combination of plasmid, ultrasound and microbubbles to approach feasibility of microbubble-enhanced ultrasound enhance PEDFgene expression; For in vivo animal studies, CNV was induced by argon lasgon laser in rats. These rats were randomly assigned to five groups and were treated by infusing microbubbles attached with the naked plasmid DNA of PEDF into the vitreous of rats followed by immediate ultrasound exposure （intravitreal injection）; infusing liposomes with the naked plasmid DNA of PEDF into the vitreous （lipofectamine ＋ PEDF）; infusing microbubbles attached with PEDF into the orbit of rats with ultrasound irradiation immediately （retrobular injection）; infusing microbubbles attached with PEDF into the femoral vein of rats with exposed to ultrasound immediately （vein injection）. The CNV rats without any treatment served as control. Rats were sacrificed and eyes were enucleated at 7, 14, and 28 days after treatment. Gene and protein expression of PEDF was detected by quantitative real-time RT-PCR, Western blotting and immunofluorescence staining, respectively. The effect of PEDF gene transfer on CNV was examined by fluorescein fundus angiography.Results In vitro cell experiments showed that microbubbles with ultrasound irradiation could significantly enhance PEDF delivery as compared with microbubbles or ultrasound alone. In the rat CNV model, transfection efficiency mediated by ultrasound/microbubbles was significantly higher than that by lipofectamine-mediated gene transfer at 28 days after treatment. The study also showed that with the administration of ultrasound-mediated microbubbles destruction, the CNV of rats was inhibited effectively. Conclusions Ultrasound-microbubble technique could increase PEDF gene transfer into rats＇ retina and chorioid, in association with a significant inhibition of the development of CNV, suggesting that this noninvasive gene transfer method may provide a useful tool for clinical gene therapy.

Anti-inflammatory effects of a synthetic peptide derived from pigment epithelium-derived factor on H2O2-induced corneal injury in vitro

Background The common pathological characteristics of corneal injury include inflammatory factors activation, vascular endothelial cells or inflammatory cells infiltration into lesions, corneal edema, corneal neovascularization （CNV）, and scar formation. PEDF-34 is the functional fragment of pigment epithelium-derived factor （PEDF） that has anti-angiogenic and anti-inflammatory properties and contains an N-terminal 34-amino acid peptide. This study was to investigate the anti- inflammatory effects of PEDF-34 on H202-induced corneal injury in vitro. Methods After cultured in H202 （0.1 mmol/L） for 2 hours, human corneal fibroblasts （HCFs） and human umbilical vein endothelial cells （HUVECs） were treated with PEDF-34-nanoparticles （NPs） at different concentrations （0.1, 0.5, 1.0, 2.0 μg/ml） or 2.0 μg/ml controI-NPs for 24 hours. The viable cells were quantified using the MTT assay. Western blotting or ELISA analysis was performed for measuring the human vascular endothelial growth factor （VEGF） and intercellular adhesion molecule-1 （ICAM-1） expression of both HCFs and HUVECs. VEGF and nuclear factor KB （NF-KB） mRNA levels of HCFs were semi-quantified by RT-PCR. Results The survival rates of HCFs or HUVECs stimulated by H202 did not decrease significantly （P 〉0.05） compared to those in the normal conditions. As compared to controI-NP group, PEDF-34-NPs had dose-dependent inhibitive effect on HUVECs with the MTT assay, but not HCFs. Western blotting analysis showed that the VEGF and ICAM-1 levels in the HCFs and HUVECs stimulated by H202 were significantly higher than those in the normal conditions, which were decreased dramatically in those treated with PEDF-34-NPs. RT-PCR analysis revealed that the VEGF mRNA and NF-KB mRNA levels increased in H202-stimulated HCFs, while both of them decreased in PEDF-34-NP groups dose dependently. Conclusions PEDF-34-NPs may play an important role in regulating the NF-kB pathway, inhibiting inflammatory activity. PEDF-34-NPs may be a potential new drug for treating corneal injury in the future.

Predictive Value of Serum Vascular Endothelial Growth Factor and Pigment Epithelium-derived Factor in Ovarian Hyperstimulation Syndrome

Objective To explore whether the serum concentrations of vascular endothelial growth factor （VEGF） and pigment epithelium-derived factor （PEDF） could serve as the predictors of ovarian hyperstimulation syndrome （OHSS） in patients undergoing in vitro fertilization-embryo transfer （IVF-ET）. Methods Enzyme-linked immunoadsordent assay （ELISA） was employed to measure the serum concentrations of VEGF and PEDF on the day of hCG administration, oocyte retrieval and embryo transfer, respectively. Based on OHSS classification of the criteria of Golan, 85 patients were divided into three groups. Patients in group A （n=10） showed symptoms of severe OHSS and patients in group B （n=13） suffered from moderate OHSS. The control group （group C, n=62） contained patients without symptoms of OHSS as well as patients with mild OHSS.Results In groups A, B and C, serum concentrations of PEDF on the day of hCG administration （h-PEDF）（166.54 ± 102.81 pg/ml, 159.45 ±136. 77 pg/ml, 172.05±170.95 pg/ml, P=0.48）, oocyte retrieval （o-PEDF）（176.91 ± 103.37 pg/ml, 122.52± 92.54 pg/ml, 179.82±177.47 pg/ml, P=0.27） and embryo transfer （e-PEDF）（169.02± 240.08 pg/ml, 136.80 ±139.21pg/ml, 157.38 ±222.54 pg/ml, P=0.95）, h-VEGF （175.55 ± 103.54 pg/ml, 218.84 ±179.70pg/ml, 153.39±145.06 pg/ml, P=0.36） and o- VEGF （171.93 ± 128.55 pg/ml, 220.36±149.82 pg/ml, 138. 74 ±% 139.30 pg/ml, P=0. 15） showed no significant differences. There was a statistical difference in serum concentration of e-VEGF between group A （197.04±156.63 pg/ml） and group C （110.69±49.55 pg/ml）（P=0.008）. The serum level of estradiol showed a positive correlation with the count of large follicles （r=0. 744）. The ratios of h-VEGF/h-PEDF, o-VEGF/o-PEDF and e-VEGF/e-PEDF were calculated and showed a clear difference among groups A, B and C （4.04±3.39, 2.10±2.14, 1.05± 4.80, P〈0.001; 4.54 5.69, 2.29 ±1.67, 0.94 ±0.59, P〈0.001; 5.43±6.16, 1.81±1.36, 2.42±2.60, P=0.04）. Conclusion While neither serum concentrations of VEGF nor PEDF can be used as an OHSS predictor, the ratios of h-VEGF/h-PEDF, o-VEGF/o-PEDF and e-VEGF/e-PEDF may have great predictive value.

Role of pigment epithelium-derived factor on proliferation and migration of choroidal capillary endothelium induced by vascular endothelial growth factor in vitro

Background Pigment epithelium-derived factor （PEDF） is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we investigated the effect of PEDF in an in vitro model of ocular choroidal neovascularization. Methods Microdissection was used to isolate the human choroidal endothelial cells （CECs）, followed by the use of superparamagnetic beads （Dynabeads） coated with the CD31 antibody, which selectively binds to the endothelial cell surface. The mitogenic and motogenic effects of vascular endothelial growth factor （VEGF） on cultured choroidal capillary endothelial cells were examined in the presence or absence of PEDF （1, 10, 100, and 1000 ng/ml） using cell counts and migration assays. Results Cells bound to the beads were isolated using a magnetic particle concentrator and they were successfully cultured and characterized to be endothelial cells that possessed greater than 95% immunoreactivity to von Willebrand factor. PEDF suppressed the proliferation and migration of VEGF-induced choroidal capillary endothelial cells. However, the concentration of PEDF which we used has little effect on normal CECs. Conclusions PEDF played an important role on the growth and migration of VEGF-stimulated choroidal endothelial cell These findings suggest that PEDF may be an effective approach to the treatment of choroidal neovascular disorders.

Hepatocyte growth factor promotes retinal pigment epithelium cell activity through MET/AKT signaling pathway

AIM:To explore the effects of hepatocyte growth factor(HGF)on retinal pigment epithelium(RPE)cell behaviors.METHODS:The human adult retinal pigment epithelial cell line-19(ARPE-19)were treated by HGF or mesenchymalepithelial transition factor(MET)inhibitor SU11274 in vitro.Cell viability was detected by a Cell Counting Kit-8 assay.Cell proliferation and motility was detected by a bromodeoxyuridine incorporation assay and a wound healing assay,respectively.The expression levels of MET,phosphorylated MET,protein kinase B(AKT),and phosphorylated AKT proteins were determined by Western blot assay.The MET and phosphorylated MET proteins were also determined by immunofluorescence assay.RESULTS:HGF increased ARPE-19 cells’viability,proliferation and migration,and induced an increase of phosphorylated MET and phosphorylated AKT proteins.SU11274 significantly reduced cell viability,proliferation,and migration and decreased the expression of MET and AKT proteins.SU11274 suppressed HGF-induced increase of viability,proliferation,and migration in ARPE-19 cells.Additionally,SU11274 also blocked HGF-induced phosphorylation of MET and AKT proteins.CONCLUSION:HGF enhances cellular viability,proliferation,and migration in RPE cells through the MET/AKT signaling pathway,whereas this enhancement is suppressed by the MET inhibitor SU11274.HGF-induced MET/AKT signaling might be a vital contributor of RPE cells survival.

Inhibition of EGFR attenuates EGF-induced activation of retinal pigment epithelium cell via EGFR/AKT signaling pathway

AIM:To explore the effect of epidermal growth factor receptor(EGFR)inhibition by erlotinib and EGFR siRNA on epidermal growth factor(EGF)-induced activation of retinal pigment epithelium(RPE)cells.METHODS:Human RPE cell line(ARPE-19 cells)was activated by 100 ng/mL EGF.Erlotinib and EGFR siRNA were used to intervene EGF treatment.Cellular viability,proliferation,and migration were detected by methyl thiazolyl tetrazolium(MTT)assay,bromodeoxyuridine(BrdU)staining assay and wound healing assay,respectively.EGFR/protein kinase B(AKT)pathway proteins and N-cadherin,α-smooth muscle actin(α-SMA),and vimentin were tested by Western blot assay.EGFR was also determined by immunofluorescence staining.RESULTS:EGF treatment for 24h induced a significant increase of ARPE-19 cells’viability,proliferation and migration,phosphorylation of EGFR/AKT proteins,and decreased total EGFR expression.Erlotinib suppressed ARPE-19 cells’viability,proliferation and migration through down regulating total EGFR and AKT protein expressions.Erlotinib also inhibited EGF-induced an increase of proliferative and migrative ability in ARPE-19 cells and clearly suppressed EGF-induced EGFR/AKT proteins phosphorylation and decreased expression of N-cadherin,α-SMA,and vimentin proteins.Similarly,EGFR inhibition by EGFR siRNA significantly affected EGF-induced an increase of cell proliferation,viability,and migration,phosphorylation of EGFR/AKT proteins,and up-regulation of N-cadherin,α-SMA,and vimentin proteins.CONCLUSION:Erlotinib and EGFR-knockdown suppress EGF-induced cell viability,proliferation,and migration via EGFR/AKT pathway in RPE cells.EGFR inhibition may be a possible therapeutic approach for proliferative vitreoretinopathy(PVR).

Regulation role of miR-204 on SIRT1/VEGF in metabolic memory induced by high glucose in human retinal pigment epithelial cells

AIM:To examine the regulatory role of microRNA-204(miR-204)on silent information regulator 1(SIRT1)and vascular endothelial growth factor(VEGF)under highglucose-induced metabolic memory in human retinal pigment epithelial(hRPE)cells.METHODS:Cells were cultured with either normal(5 mmol/L)or high D-glucose(25 mmol/L)concentrations for 8d to establish control and high-glucose groups,respectively.To induce metabolic memory,cells were cultured with 25 mmol/L D-glucose for 4d followed by culture with 5 mmol/L D-glucose for 4d.In addition,exposed in 25 mmol/L D-glucose for 4d and then transfected with 100 nmol/L miR-204 control,miR-204 inhibitor or miR-204 mimic in 5 mmol/L D-glucose for 4d.Quantitative reverse transcription-polymerase chain reaction(RT-qPCR)was used to detect miR-204 mRNA levels.SIRT1 and VEGF protein levels were assessed by immunohistochemical and Western blot.Flow cytometry was used to investigate apoptosis rate.RESULTS:It was found that high glucose promoted miR-204 and VEGF expression,and inhibited SIRT1 activity,even after the return to normal glucose culture conditions.Upregulation of miR-204 promoted apoptosis inhibiting SIRT1 and increasing VEGF expression.However,downregulation of miR-204 produced the opposite effects.CONCLUSION:The study identifies that miR-204 is the upstream target of SIRT1and VEGF,and that miR-204 can protect hRPE cells from the damage caused by metabolic memory through increasing SIRT1 and inhibiting VEGF expression.

Pigment epithelium derived factor(PEDF)prevents methyl methacrylate monomer-induced cytotoxicity in H9c2 cells

Acrylic bone cements are currently the most frequently and extensively used materials in orthopedic implant treatment. However, adverse effects have been described of acrylic bone cement on the cardiovascular system. In the present study, we examined the cytotoxicity of bone cement ingredient methyl methacrylate（MMA） to cardiomyocytes and the potential detoxifying effect of pigment epithelium-derived factor（PEDF） in H9c2 cells.We found that high concentration of MM A（〉 120 mmol/L） led to necrotic cell death in H9c2 cells. However, MMA at low concentrations（30-90 mmol/L） caused apoptosis. Pretreatment of PEDF prevented MMA-induced cytotoxicity. In addition, PEDF enhanced total superoxide dismutase activities, and decreased MMA-induced production of malonaldehyde. Furthermore, MMA-induced downregulation of Akt activity was suppressed by PEDF.PEDF also increased the levels of peroxisome proliferator activated receptor gamma（PPARγ）and lysophosphatidic acids（LPA） through PEDF receptor. These results indicated that PEDF inhibited MMA-induced cytotoxicity through attenuating oxidative stress, activating the phosphatidylinositol 3-kinase（PI3K）/Akt pathway and/or PEDF receptorLPA-PPARy pathways in H9c2 cells. PEDF may be explored as a candidate therapeutic agent for alleviating bone cement implantation syndrome during orthopedic surgery.

Oxidative stress affects retinal pigment epithelial cell survival through epidermal growth factor receptor/AKT signaling pathway

AIM：To investigate the cross-talk between oxidative stress and the epidermal growth factor receptor（EGFR）/AKT signaling pathway in retinal pigment epithelial（ RPE） cells.METHODS：Human RPE cell lines（ARPE-19 cell） were treated with different doses of epidermal growth factor（EGF） and hydrogen peroxide（H2O2）.Cell viability was determined by a methyl thiazolyl tetrazolium assay.Cell proliferation was examined by a bromodeoxyuridine（Brd U） incorporation assay.EGFR/AKT signaling was detected by Western blot.EGFR localization was also detected by immunofluorescence.In addition,EGFR/AKT signaling was intervened upon by EGFR inhibitor（erlotinib）,PI3 K inhibitor（A66） and AKT inhibitor（MK-2206）,respectively.H2O2-induced oxidative stress was blocked by antioxidant N-acetylcysteine（NAC）.RESULTS：EGF treatment increased ARPE-19 cell viabili ty and proliferation through inducing phosphorylation of EGFR and AKT.H2O2 inhibited ARPE-19 cell viability and proliferation and also suppressed EGF-stimulated increase of RPE cell viability and proliferation by affecting the EGFR/AKT signaling pathway.EGFR inhibitor erlotinib blocked EGF-induced phosphorylation of EGFR and AKT,while A66 and MK-2206 only blocked EGF-induced phosphorylation of AKT.EGF-induced phosphorylation andendocytosis of EGFR were also affected by H2O2 treatment.In addition,antioxidant NAC attenuated H2O2-induced inhibition of ARPE-19 cell viability through all eviating reduction of EGFR,and phosphorylated and total AKT proteins.CONCLUSION：Oxidative stress affects RPE cell viability and proliferation through interfering with the EGFR/AKT signaling pathway.The EGFR/AKT signaling pathway may be an important target in oxidative stress-induced RPE cell dysfunction.

The effects of anti-vascular endothelial growth factor agents on human retinal pigment epithelial cells under high glucose conditions

AIM： To investigate the effects of high glucose levels and anti-vascular endothelial growth factor（VEGF） agents（bevacizumab,ranibizumab and aflibercept） on retinal pigment epithelium（RPE） cells.METHODS： ARPE-19 cells were cultured at different glucose levels（5.5 mmol/L,25 mmol/L,and 75 mmol/L）.Cell viability was evaluated by MTT assay at 3d after treatment with D-glucose.Cell migration ability was measured by wound healing assay at 3d.A cell death detection kit was used to assess apoptosis at 3 and 14 d.Cell proliferation was assessed by EdU assay at 3d.The culture medium was treated with anti-VEGF agents at clinically relevant concentrations.The experiment was then repeated at a different glucose level.RESULTS： The viability and migration of ARPE-19 cells were significantly decreased in the presence of 75 mmol/L as compared to 5.5 mmol/L glucose.The percentage of TUNEL-positive cells was significantly increased and the proliferative potential was decreased with 75 mmol/L compared to 5.5 mmol/L glucose.There were no significant differences in the results between 25 mmol/L and 5.5 mmol/L glucose.In the presence of 75 mmol/L glucose,the groups treated with anti-VEGF showed decreased cell viability and proliferation and increased apoptosis.However,there were no significant differences between the anti-VEGF groups.CONCLUSION： High glucose level decreases the viability,wound healing ability,and proliferation of RPE cells,while increasing apoptosis.Furthermore,anti-VEGF agents interfered with the physiological functions of RPE cells under high-glucose conditions,accompanied by decreases in cell viability and proliferation.

Construction of a plasmid for human brain-derived neurotrophic factor and its effect on retinal pigment epithelial cell viability

Several studies have investigated the protective functions of brain-derived neurotrophic factor（BDNF） in retinitis pigmentosa. However, a BDNF-based therapy for retinitis pigmentosa is not yet available. To develop an efficient treatment for fundus disease, an eukaryotic expression plasmid was generated and used to transfect human 293 T cells to assess the expression and bioactivity of BDNF on acute retinal pigment epithelial-19（ARPE-19） cells, a human retinal epithelial cell line. After 96 hours of co-culture in a Transwell chamber, ARPE-19 cells exposed to BDNF secreted by 293 T cells were more viable than ARPE-19 cells not exposed to secreted BDNF. Western blot assay showed that Bax levels were downregulated and that Bcl-2 levels were upregulated in human ARPE-19 cells exposed to BDNF. Furthermore, 293 T cells transfected with the BDNF gene steadily secreted the protein. The powerful anti-apoptotic function of this BDNF may be useful for the treatment of retinitis pigmentosa and other retinal degenerative diseases.

Effects of Nerve Growth Factor on Proliferation and DNA Synthesis of Cultured Human Fetal Retinal Pigment Epithelium Cells

Objective: To investigate the effects of nerve growth factor(NGF)on proliferation and DNAthesis of cultured human fetal retinal pigment epithelium (RPE)cells in vitro.Methods: Primary culture and subculture of human fetal retinal pigment epithelium cellswere established in vitro first. Cultured RPE cells were treated with NGF by variousconcentrations 0μg/L, 50μg/L, 100μg/L, 200μg/L and 300μg/L(final concentration)for 48 hs.After 48 hs, cells proliferation was measured with methyl thiazolyl tetrazolium(MTT)assay method and the amount of DNA was determined by the absorbance at 280nm of nucleic acid & protein analysis.Results: The A values of 100 μg/L, 200 μg/L, 300 μg/L NGF was(0. 213 7 ± 0. 23 3),(0. 218 8 ±0. 018 1), (0. 232 2 ±0. 016 4) as compared with(0. 189 7 ±0. 015 2) of Avalue of 0 μg/L NGF respectively, q value was 3.63,4.40, 6. 42 and P value was0. 015, 0. 000, 0. 000(q-test). The DNA concentrations of 100 μg/L, 200 μg/L, 300μg/L and 400 μg/L NGF was (981. 220 4 ± 123.535 7), (1 375. 848 4 ±244. 471 8),(1 658.707 1 ± 176. 938 1), (2 353.086 3 ±609. 906 4) μg/ml as compared with(666. 818 8 ± 141. 330 2) μg/ml of DNA concentration of 0 μg/L NGF respectively, qvalue was 3.63,8.20,11.47,19.46, P value was 0. 024,0. 000,0. 000,0. 000 (q-test).Conclusion: The data suggested that NGF could stimulate the proliferation and DNAsynthesis of cultured of hRPE cells in vitro in a dose-dependent manner.