CircZNF609 inhibits miR-150-5p to promote high glucose-induced damage to retinal microvascular endothelial cells.

Hyperglycemia is a key contributor to diabetic macrovascular and ocular complications. It triggers a cascade of cellular damage, particularly in the retinal microvascular endothelial cells (RMECs). However, the underlying molecular mechanisms remain only partially understood. This study hypothesizes that CircZNF609 plays a pivotal role in mediating high glucose-induced damage in RMECs by modulating miR-150-5p and its downstream target genes, thereby affecting cellular survival, apoptosis, and oxidative stress. Gene expression datasets (GSE193974 and GSE160308) and clinical samples were used to investigate the expression levels of CircZNF609 and its interaction with miR-150-5p in the context of diabetic retinopathy (DR). Our results demonstrate that CircZNF609 is upregulated in both peripheral blood stem cells from DR patients and high glucose-stimulated hRMECs. Functional experiments reveal that silencing CircZNF609 improves cell viability, reduces apoptosis, inhibits tube formation, and modulates oxidative stress markers, whereas CircZNF609 overexpression exacerbates these effects. Moreover, miR-150-5p, a microRNA, was found to be negatively regulated by CircZNF609 and downregulated in DR. Its overexpression mitigates high glucose-induced cell injury. Our findings suggest a novel mechanism whereby CircZNF609 exacerbates high glucose-induced endothelial cell damage by sponging miR-150-5p, implicating the CircZNF609/miR-150-5p axis as a potential therapeutic target in diabetic retinopathy.

High Vasohibin-2 expression correlated with autophagy in proliferative diabetic retinopathy.

Vasohibin-2 (VASH2) is confirmed to be associated with angiogenesis. To investigate the vitreous levels of VASH2 and how VASH2 induces angiogenesis in proliferative diabetic retinopathy (PDR), a total of 120 eyes were enrolled in this prospective and randomized controlled study and the vitreous level of VASH2 was quantified by Luminex liquid suspension chip. Vector systems were applied in human retinal microvascular endothelial cells (HRMECs) for VASH2 gene overexpression, along with interfering lentiviral vectors (VASH2-shRNA) for VASH2 gene silencing. Cell migration, autophagic flux, as well as the expression of α-tubulin, detyrosinated ⍺-tubulin, LC3 II/LC3 I, P62 were detected under normal, VASH2 overexpression, or interference conditions. The level of VASH2 in PDR patients was significantly higher (218.61 ± 30.14 pg/ml) than that in ERM/MH patients (80.78 ± 2.05 pg/ml) (P = 0.001). The migration ability of HRMECs was significantly increased in VASH2 overexpression group, while in the interfering group, the migration ability decreased. VASH2 increased the detyrosination of ⍺-tubulin. The high fluorescence intensity of autophagic flux showed an activation of autophagy in VASH2 overexpression group, which was also confirmed by the increase of LC3 II/LC3 I ratio and the decrease of P62. Collectively, the present study shows in PDR, vitreous level of VASH2 is higher. VASH2 promotes neovascularization by inducing autophagy, suggesting VASH2 could be a new anti-angiogenic drug target for PDR.

Knockdown of ChREBP ameliorates retinal microvascular endothelial cell injury and angiogenic responses in diabetic retinopathy.

PURPOSE: To examine whether and how carbohydrate response element-binding protein (ChREBP) plays a role in diabetic retinopathy. METHODS: Western blotting was used to detect ChREBP expression and location following high glucose stimulation of Human Retinal Microvascular Endothelial Cells (HRMECs). Flow cytometry, TUNEL staining, and western blotting were used to evaluate apoptosis following ChREBP siRNA silencing. Cell scratch, transwell migration, and tube formation assays were used to determine cell migration and angiogenesis. Diabetic models for wild-type (WT) and ChREBP knockout (ChKO) mice were developed. Retinas of WT and ChKO animals were cultivated in vitro with vascular endothelial growth factor + high glucose to assess neovascular development. RESULTS: ChREBP gene knockdown inhibited thioredoxin-interacting protein and NOD-like receptor family pyrin domain containing protein 3 expression in HRMECs, which was caused by high glucose stimulation, reduced apoptosis, hindered migration, and tube formation, and repressed AKT/mTOR signaling pathway activation. Compared with WT mice, ChKO mice showed suppressed high glucose-induced alterations in retinal structure, alleviated retinal vascular leakage, and reduced retinal neovascularization. CONCLUSIONS: ChREBP deficiency decreased high glucose-induced apoptosis, migration, and tube formation in HRMECs as well as structural and angiogenic responses in the mouse retina; thus, it is a potential therapeutic target for diabetic retinopathy.

Role of apigenin in high glucose-induced retinal microvascular endothelial cell dysfunction via regulating NOX4/p38 MAPK pathway in vitro.

AIM: To investigate the retinoprotective role of Apigenin (Api) against high glucose (HG)-induced human retinal microvascular endothelial cells (HRMECs), and to explore its regulatory mechanism. METHODS: HRMECs were stimulated by HG for 48h to establish the in vitro cell model. Different concentrations of Api (2.5, 5, and 10 µmol/L) were applied for treatment. Cell counting kit-8 (CCK-8), Transwell, and tube formation assays were performed to examine the effects of Api on the viability, migration, and angiogenesis in HG-induced HRMECs. Vascular permeability was evaluated by Evans blue dye. The inflammatory cytokines and oxidative stress-related factors were measured using their commercial kits. Protein expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) and p38 mitogen-activated protein kinase (MAPK) was measured by Western blot. RESULTS: Api prevented HG-induced HRMECs viability, migration, angiogenesis, and vascular permeability in a concentration-dependent manner. Meanwhile, Api also concentration-dependently inhibited inflammation and oxidative stress in HRMECs exposed to HG. In addition, HG caused an elevated expression of NOX4, which was retarded by Api treatment. HG stimulation facilitated the activation of p38 MAPK signaling in HRMECs, and Api could weaken this activation partly via downregulating NOX4 expression. Furthermore, overexpression of NOX4 or activation of p38 MAPK signaling greatly weakened the protective role of Api against HG-stimulated HRMECs. CONCLUSION: Api might exert a beneficial role in HG-stimulated HRMECs through regulating NOX4/p38 MAPK pathway.

miR-519d-3p alleviates high glucose-induced human retinal microvascular endothelial cells dysfunction and inhibits angiogenesis by targeting hypoxia inducible factor 1 subunit alpha / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To clarify the effect of miR-519d-3p on high glucose-induced human retinal microvascular endothelial cells(HRMEC)dysfunction and angiogenesis, and to elucidate the regulatory mechanism of miR-519d-3p on hypoxia inducible factor 1 subunit alpha(HIF-1α).METHODS: The normal glucose(NG)and high glucose(HG)cell models were established by inducing HRMEC with 5 and 30 mmol/L glucose, respectively. Control group: HG cell model was transfected with negative control mimics; mannitol group: the control group was added with 25 mmol/L mannitol; miR-519d-3p overexpression group: HG cell model was transfected with miR-519d-3p mimics; miR-519d-3p combined with HIF-1α overexpression group: HG cell model was co-transfected with miR-519d-3p mimics and HIF-1α overexpression vector. The expression of miR-519d-3p in each group was tested by real-time fluorescence quantitative PCR. The expression of HIF-1α protein in each group was tested by Western blotting. The binding sites between miR-519d-3p and HIF-1α were detected by luciferase reporter gene assay. The cell proliferation of each group was detected by CCK-8. The cell apoptosis of each group was tested by Hoechst 33342 staining. The protein expression of extracellular fluid inflammatory factors tumor necrosis factor-α(TNF-α), interleukin(IL)-1β and IL-6 in each group was tested by ELISA. The formation of new capillary lumen-like structures was detected by tubule formation assay.RESULTS: Compared with the NG, miR-519d-3p expression was significantly reduced in the HG cell model, while HIF-1α protein expression was significantly increased in the HG(all P<0.01). Compared with the control group, HIF-1α protein expression was significantly reduced in the miR-519d-3p overexpression group(P<0.01). The “CGUGAAA” sequence of miR-519d-3p could specifically bind to the “GCACUUU” sequence of HIF-1α 3'-untranslated region(3'-UTR). Compared with the control group, the miR-519d-3p overexpression group showed a significant increase in 24, 48 and 72h absorbance values, a significant decrease in cell apoptotic rate, a significant decrease in the concentrations of TNF-α, IL-1β and IL-6, and a significant decrease in the number of new capillary lumen-like structures(all P<0.01). Compared with the miR-519d-3p overexpression group, the miR-519d-3p combined with HIF-1α overexpression group showed a significant decrease in 24, 48 and 72h absorbance values, a significant increase in cell apoptotic rate, a significant increase in the concentrations of TNF-α, IL-1β and IL-6, and a significant increase in the number of new capillary lumen-like structures(all P<0.01). There was no difference between the control group and mannitol group in the comparison of the above indicators(all P>0.05).CONCLUSION: miR-519d-3p expression is down-regulated while HIF-1α protein expression is up-regulated in high glucose induced HRMEC model. HIF-1α is a target gene of miR-519d-3p. The miR-519d-3p targets HIF-1α to increase cell proliferation and reduce cell apoptosis and inflammation, thereby alleviating high glucose-induced HRMEC dysfunction and inhibiting angiogenesis.

Downregulation of acylglycerol kinase suppresses high-glucose-induced endothelial-mesenchymal transition in human retinal microvascular endothelial cells through regulating the LPAR1/TGF-ß/Notch signaling pathway.

The endothelial-mesenchymal transition (EndMT) participates in the progression of diabetic retinopathy (DR), but cell-intrinsic factors modulating this process remain elusive. In this study, we explored the role of lysophosphatidic acid (LPA) - producing enzyme, acylglycerol kinase (AGK), in the EndMT of human retinal microvascular endothelial cells (HRECs) under high-glucose (HG) conditions. We found that AGK was significantly elevated in HG-treated cells. In addition, AGK knockdown reversed the HG-induced EndMT in HRECs, which was evidenced by the increased endothelial markers (CD31 and VE-cadherin) and decreased mesenchymal markers (FSP1 and α-SMA). Furthermore, downregulation of AGK inhibited the HG-induced activation of transforming growth factor ß (TGF-ß)/Notch pathways, whereas exogenous TGF-ß1 (10 ng/mL) impeded the inhibitory effects of AGK knockdown on HG-induced EndMT in HRECs. Additionally, the silencing of AGK abolished the HG-induced upregulation of LPA and its receptor, LPA receptor 1 (LPAR1), and overexpression of LPAR1 further rescued the AGK knockdown-mediated inhibition of the EndMT process. In conclusion, we demonstrate that downregulation of AGK suppresses HG-induced EndMT in HRECs through regulating the LPAR1/TGF-ß/Notch signaling pathway, indicating that AGK might be a potential therapeutic target for the treatment of DR.

Upregulation of long non-coding RNA SNHG16 promotes diabetes-related RMEC dysfunction via activating NF-κB and PI3K/AKT pathways.

Diabetic retinopathy (DR) is a severe diabetes-induced eye disease, in which its pathological phenomena basically include abnormal proliferation, migration, and angiogenesis of microvascular endothelial cells in the retina. Long non-coding RNAs (lncRNAs) have been proven to be important regulators in various biological processes, but their participation in DR remains largely undiscovered. In the present study, we aimed to unveil the role of lncRNA small nucleolar RNA host gene 16 (SNHG16) in regulating the functions of human retinal microvascular endothelial cells (hRMECs) under a high-glucose (HG) condition. We found that SNHG16 expression was significantly upregulated in hRMECs treated with HG. Functionally, SNHG16 could facilitate hRMEC proliferation, migration, and angiogenesis. Moreover, SNHG16 was associated with nuclear factor κB (NF-κB) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. Mechanistically, SNHG16 could promote hRMEC dysfunction by sequestering microRNA (miR)-146a-5p and miR-7-5p to act as a competing endogenous RNA (ceRNA) with interleukin-1 receptor-associated kinase 1 (IRAK1) and insulin receptor substrate 1 (IRS1). In conclusion, our results illustrated the potential role of SNHG16 in facilitating hRMEC dysfunction under HG treatment, providing a novel approach for DR therapy.

microRNA-216a protects against human retinal microvascular endothelial cell injury in diabetic retinopathy by suppressing the NOS2/JAK/STAT axis.

OBJECTIVE: Since microRNAs (miRNAs) represent as effective therapeutic targets for diabetic retinopathy (DR), we identified aberrantly expressed miRNAs related to cellular dysfunction in DR and further detected their potential targets. This study aimed to explore the synergistic effect of miR-216a, inducible nitric oxide synthase 2 (NOS2) and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway on human retinal microvascular endothelial cell (HRMEC) injury in DR. METHODS: The differentially expressed genes in DR were obtained by GEO database, and the downstream signaling pathways and upstream targeted miRNAs were obtained through bioinformatics analysis. Subsequently, a DR model rat was established, and the target miR-216a was overexpressed to observe the pathological and morphological changes of the rat retina and the levels of inflammatory factors. Then, HRMECs were extracted and added with d-Glucose, and then transfected with miR-216a, NOS2 or adding JAK/STAT signaling pathway specific inhibitor to observe changes in cell activity and inflammatory damage. RESULTS: NOS2 was significantly upregulated, and the JAK/STAT signaling pathway was significantly activated in DR. miR-216a targeted NOS2, which played a protective role in the retina of DR rats. Moreover, in cell experiments, overexpression of miR-216a promoted the viability of HRMECs under d-glucose treatment, and inhibited NOS2 expression and the JAK/STAT signaling pathway activation. CONCLUSION: This study suggests that miR-216a protects against HRMECs injury in DR by suppressing the NOS2/JAK/STAT axis.

MicroRNA-29b-3p Promotes Human Retinal Microvascular Endothelial Cell Apoptosis via Blocking SIRT1 in Diabetic Retinopathy.

BACKGROUND: Diabetic retinopathy (DR) is a main complication of diabetes mellitus (DM). Recent studies have implicated microRNAs in human retinal microvascular endothelial cell (HRMEC) dysfunction. In this study, we aim to investigate the apoptotic promotion of miR-29b-3p by blocking SIRT1 in HRMEC for DR situation. METHOD: Blood samples were obtained from DR patients and controls. Dual-luciferase reporter assay using HEK-293T cells was performed to show the direct interaction of miR-29b-3p and the 3'UTR of SIRT1. HRMECs were exposed to 5.5 mmol/L of glucose (normal control), 5.5 mmol/L of glucose and 24.5 mmol/L of mannitol (osmotic pressure control), 30 mmol/L of glucose [hyperglycemia (HG)], 150 µmol/L of CoCl2 (hypoxia), and 30 mmol/L of glucose plus 150 µmol/L of CoCl2 (HG-CoCl2). To identify the regulating relationship between miR-29b-3p and SIRT1, HRMECs were transfected with miR-29b-3p mimics/inhibitors or their negative controls. SRT1720 was used as a SIRT1 agonist. Cell viability was assessed with the cell counting kit-8 (CCK-8) assay, and apoptotic cells were stained by one-step terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay kit. Gene and protein expression were assayed by quantitative real-time reverse transcriptase-PCR (RT-qPCR) and western blotting separately. RESULT: MiR-29b-3p was upregulated to 3.2-fold, and SIRT1 protein was downregulated to 65% in DR patients. Dual-luciferase reporter assay showed the direct interaction of miR-29b-3p and SIRT1. HRMECs were identified as >95% positive for CD31 and von Willebrand factor (vWF). MiR-29b-3p and Bax/Bcl-2 ratio was upregulated, whereas SIRT1 was downregulated in HRMECs in the HG-CoCl2 condition. Decreased cell viability and upregulated apoptosis were also found in HRMECs of the HG-CoCl2 condition. Upregulated miR-29b-3p decreased the expression of SIRT1 and increased the ratio of Bax/Bcl-2, whereas downregulated miR-29b-3p increased the expression of SIRT1 protein and downregulated the ratio of Bax/Bcl-2. SRT1720 rescued miR-29b-3p-induced HRMEC apoptosis via upregulating the expression of SIRT1 protein. CONCLUSION: The dysregulation of miR-29b-3p/SIRT1 is a potential mechanism of HRMEC apoptosis in DR. MiR-29b-3p/SIRT1 may be a potential therapeutic target for DR.

Effect and potential signaling pathway of hedgehog protein on the function of human retinal microvascular endothelial cell / 中华实验眼科杂志

Objective To explore the impact of Hedgehog protein on human retinal microvascular endothelial cell(HRMEC) and its signaling pathway. Methods The cultured HRMECs were divided into normal control group,0. 5μmol/L agonist group and 1. 0μmol/L agonist group,and were cultured in medium with final concentration of 0,0. 5 and 1. 0μmol/L Hedgehog agonist,respectively;HRMECs cultured in high glucose medium were divided into high glucose control group,1. 5μmol/L inhibitor group and 2. 5μmol/L inhibitor group. Erismodegib,the Smoothed inhibitor with final concentration of 0,1. 5 and 2. 5 μmol/L was added into corresponding group,respectively. MTS method and Transwell cell migration method were used to detect the proliferation( A490 value) and relative mobility of HRMEC. The phosphorylation of PLCγ1, Akt and Erk proteins were detected by Western blot. Results The relative expression of Hedgehog protein in the high glucose control group was 6. 24±0. 11,which was significantly higher than 1. 00±0. 00 in the normal control group(t=667. 573,P<0. 001). The A490 value was 1. 349±0. 050 and 1. 422±0. 053,and the relative mobility rate was 2. 34±0. 14 and 3. 59±0. 32 in the 0. 5μmol/L agonist group and the 1. 0μmol/L agonist group, respectively, which were significantly higher than 1. 203 ± 0. 101 and 1. 00 ± 0. 00 in the normal control group(all at P<0. 01). The A490 value was 0. 849±0. 010 and 0. 737±0. 030,and the relative mobility rate was 0. 43 ± 0. 02 and 0. 27 ± 0. 01 in the 1. 5 μmol/L inhibitor group and the 2. 5 μmol/L inhibitor group, respectively,which were significantly lower than 1. 000±0. 040 and 1. 00±0. 00 in the high glucose control group(all at P<0. 01). The phosphorylation ratios of PLCγ1,Akt and Erk in the 0. 5μmol/L agonist group and the 1. 0μmol/L agonist group were significantly higher than those in the normal control group ( all at P<0. 01 ) . The phosphorylation ratios of PLCγ1,Akt and Erk in the 1. 5μmol/L inhibitor group and the 2. 5μmol/L inhibitor group were significantly lower than those in the high glucose control group ( all at P<0. 01 ) . Conclusions High glucose induces the expression of Hedgehog protein in HRMEC. Hedgehog protein may regulate the function of HRMEC by regulating the phosphorylation of PLCγ1,Akt and Erk in G Protein-coupled receptors pathway.

Effect and potential signaling pathway of hedgehog protein on the function of human retinal microvascular endothelial cell / 中华实验眼科杂志

Objective@#To explore the impact of Hedgehog protein on human retinal microvascular endothelial cell(HRMEC)and its signaling pathway.@*Methods@#The cultured HRMECs were divided into normal control group, 0.5 μmol/L agonist group and 1.0 μmol/L agonist group, and were cultured in medium with final concentration of 0, 0.5 and 1.0 μmol/L Hedgehog agonist, respectively; HRMECs cultured in high glucose medium were divided into high glucose control group, 1.5 μmol/L inhibitor group and 2.5 μmol/L inhibitor group.Erismodegib, the Smoothed inhibitor with final concentration of 0, 1.5 and 2.5 μmol/L was added into corresponding group, respectively.MTS method and Transwell cell migration method were used to detect the proliferation(A490 value)and relative mobility of HRMEC.The phosphorylation of PLCγ1, Akt and Erk proteins were detected by Western blot.@*Results@#The relative expression of Hedgehog protein in the high glucose control group was 6.24±0.11, which was significantly higher than 1.00±0.00 in the normal control group(t=667.573, P<0.001). The A490 value was 1.349±0.050 and 1.422±0.053, and the relative mobility rate was 2.34±0.14 and 3.59±0.32 in the0.5 μmol/L agonist group and the 1.0 μmol/L agonist group, respectively, which were significantly higher than 1.203±0.101 and 1.00±0.00 in the normal control group(all at P<0.01). The A490 value was 0.849±0.010 and 0.737±0.030, and the relative mobility rate was 0.43±0.02 and 0.27 ±0.01 in the 1.5 μmol/L inhibitor group and the 2.5 μmol/L inhibitor group, respectively, which were significantly lower than 1.000±0.040 and 1.00±0.00 in the high glucose control group(all at P<0.01). The phosphorylation ratios of PLCγ1, Akt and Erk in the 0.5 μmol/L agonist group and the 1.0 μmol/L agonist group were significantly higher than those in the normal control group(all at P<0.01). The phosphorylation ratios of PLCγ1, Akt and Erk in the 1.5 μmol/L inhibitor group and the 2.5 μmol/L inhibitor group were significantly lower than those in the high glucose control group(all at P<0.01).@*Conclusions@#High glucose induces the expression of Hedgehog protein in HRMEC.Hedgehog protein may regulate the function of HRMEC by regulating the phosphorylation of PLCγ1, Akt and Erk in G Protein-coupled receptors pathway.

RNA sequencing identified specific circulating miRNA biomarkers for early detection of diabetes retinopathy.

Diabetic retinopathy (DR) is the leading cause of blindness in patients with diabetes. However, biomarkers for early detection of DR are still lacking. MicroRNAs (miRNAs) regulate multiple biological functions and are often deregulated in DR. We aimed to investigate whether circulating miRNAs can be used as biomarkers of early-stage DR. We used RNA-seq and qRT-PCR to identify differential serum miRNAs in patients with type 2 diabetes mellitus with DR (T2DM-DR), T2DM without DR (T2DM-no-DR), and healthy controls. We validated differential circulating miRNAs in two phases using qRT-PCR assays. RNA-seq analysis identified 7 differential circulating miRNAs between T2DM-DR and T2DM-no-DR and 47 differential miRNAs between T2DM-DR and healthy subjects. Two-stage analysis verified that a profile of five serum miRNAs (hsa-let-7a-5p, hsa-miR-novel-chr5_15976, hsa-miR-28-3p, has-miR-151a-5p, has-miR-148a-3p) was significantly associated with T2DM-DR. Receiver-operator-characteristic analyses showed that a panel of three miRNAs (hsa-let-7a-5p, hsa-miR-novel-chr5_15976, and hsa-miR-28-3p) presented 0.92 sensitivity and 0.94 specificity for distinguishing T2DM-DR from T2DM-no-DR, and 0.93 sensitivity and 0.86 specificity for differentiating early-stage T2DM-DR (NPDR) from late-stage DR (PDR). Lentivirus-mediated overexpression of hsa-let-7a-5p in human retinal microvascular endothelial cells (HRMECs) significantly promoted proliferation rates of HRMECs. In conclusion, the three-miRNA signature from serum may serve as a noninvasive diagnostic biomarker for DR. Furthermore, we showed that DR-associated miRNAs may be involved in the pathogenesis of DR, at least in part, through modifying proliferation of HRMECs.

Regulations of insulin on syndecan-1 expression, cellular permeability and proliferation in human retinal microvascular endothelial cells / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the effects of insulin on syndecan-1 expression, cellular permeability and proliferation in human retinal microvascular endothelial cells. <p>METHODS: Cells were treated with 100nmol/L and 1 000nmol/L insulin for 48h respectively. Expression of protein and mRNA were detected by western blot and quantitative real-time polymerase chain reaction. Cellular proliferation and permeability were examined by methods of methylthiazolyl tetrazolium and horseradish peroxidase. <p>RESULTS: With treatment of insulin, protein and mRNA of syndecan-1 both increased obviously, and the effect of high level insulin was more significant. After treated with insulin, cellular proliferation and permeability both enhanced, and the effects of high level insulin were stronger. <p>CONCLUSION: Insulin can up-regulate syndecan-1 protein and mRNA in cultured human retinal microvascular endothelial cells, and increase cellular permeability and proliferation.

Protective effect of miR-200b/c by inhibiting vasohibin-2 in human retinal microvascular endothelial cells.

AIMS: Proliferative diabetic retinopathy (PDR), characterized by angiogenesis, can cause serve vision loss and even blindness. Recent studies have suggested a pivotal role of vasohibin-2 (VASH2) in the promotion of angiogenesis in tumor tissues. Here we further investigated the role of VASH2 in the proliferation and migration of retinal endothelial cells. MAIN METHODS: The expression of VASH2 in vascular endothelial cells of epiretinal fibrovascular membranes (FVMs) from PDR patients were detected by immunofluorescence. VASH2 gene interfering lentiviral vectors (VASH2-shRNA) and miR-200b/c were constructed for the evaluation of the VASH2 effect on high glucose induced human retinal microvascular endothelial cell line (HRMECs). Cell proliferation, cell cycle and cell migration were carried out subsequently. The relationship between VASH2 and miR-200b/c was determined by luciferase reporter gene assays. KEY FINDINGS: A positive expression of VASH2 was identified in vascular endothelial cells of FVMs from PDR patients. In HRMECs, cells transfected with shRNA or miR-200b/c mimics showed a significantly reduced VASH2 expression compared with negative control group by real time-polymerase chain reaction and western-blot analysis. Inhibition of VASH2 was demonstrated to suppress cell proliferation and migration from Day 2 to Day 4. The luciferase reporter gene assays confirmed the post-transcriptional regulation of VASH2 by miR-200b/c in HRMECs. SIGNIFICANCE: The present study suggests a protective effect of miR-200b/c on high glucose induced HRMECs dysfunction by inhibiting VASH2. It could be a potential therapeutic strategy to inhibit angiogenesis for the treatment of retinal vascular disease.

Contacting co-culture of human retinal microvascular endothelial cells alters barrier function of human embryonic stem cell derived retinal pigment epithelial cells.

Here we evaluated the effects of human retinal microvascular endothelial cells (hREC) on mature human embryonic stem cell (hESC) derived retinal pigment epithelial (RPE) cells. The hESC-RPE cells (Regea08/017, Regea08/023 or Regea11/013) and hREC (ACBRI 181) were co-cultured on opposite sides of transparent membranes for up to six weeks. Thereafter barrier function, small molecule permeability, localization of RPE and endothelial cell marker proteins, cellular fine structure, and growth factor secretion of were evaluated. After co-culture, the RPE specific CRALBP and endothelial cell specific von Willebrand factor were appropriately localized. In addition, the general morphology, pigmentation, and fine structure of hESC-RPE cells were unaffected. Co-culture increased the barrier function of hESC-RPE cells, detected both with TEER measurements and cumulative permeability of FD4 - although the differences varied among the cell lines. Co-culturing significantly altered VEGF and PEDF secretion, but again the differences were cell line specific. The results of this study showed that co-culture with hREC affects hESC-RPE functionality. In addition, co-culture revealed drastic cell line specific differences, most notably in growth factor secretion. This model has the potential to be used as an in vitro outer blood-retinal barrier model for drug permeability testing.

Inhibition and mechanism of 15 (S)-hydroxyeicosate traenoic acid on proliferation of hypoxic retinal microvascular endothelial cells in vitro / 中华实验眼科杂志

Background Retninal neovascular diseases caused by hypoxia has become a major blinding disease,which is lack of effective chemical treatment currently,it's important to study the molecuar mechanism of the disease,so as to guide the clinical medication.Objective This study was to explore the effect of 15 (S)-hydroxyeicosate traenoic acid (15-HETE) on the proliferation of hypoxic retinal microvascular endothelial cells (RMVECs) and its probable mechanism.Methods RMVECs were isolated from C57BL/6J mice and incubated and then identified with anti-Ⅷ factor antibody by immunochemistry and immunofluorescence.The cells were divided into the normoxia group and the hypoxia group.The hypoxia cell models were established by treated with 125 μmol/L CoCl2.The cells were cultured with serum-free DMEM containing endothelial cell growth supplement (ECGS)and high glucose for 48 hours,and then different concentrations of 15-HETE (0.0,0.1,1.0,5.0 μmol/L) were added in the medium for 48 hours respectively to subgroup the groups.The proliferation of the cells (absorbance,A) was detected using MTT.The relative expression levels of protein and mRNA of hypoxia inducible factor-1α (HIF-1α),bcl-2 and caspase-3 were assayed by reverse transcription PCR (RT-RCR)and Western blot.Results The cells showed the positive response for anti-Ⅷ factor antibody with the positive rate of (94.38 ±4.25)％.No significant difference was found in the cell proliferation of various groups under the normoxia condition (F =0.283,P =0.837),but under the hypoxia condition,the proliferation values were significantly different among various groups (F =702.582,P＜0.001).The cell proliferation value in the 1.0 μmol/L 15-HETE group and 5.0 μmol/L 15-HETE group was lower than that of the simple hypoxia group respectively(both at P＜0.05).The inhibitory rates in the 0.1,1.0,5.0 μ mol/L 15-HETE groups were (1.09±0.31) ％,(21.09± 3.53) ％ and (49.86 ±4.15) ％,showing a dosedependent manner.No significant difference was seen in the expression levels of bcl-2,caspase-3 and HIF-1α mRNA in various groups under the normoxia conditions.However,compared with the simple normoxia group,the relative expressions of bcl-2 mRNA and HIF-1α mRNA in the cells were increased by 1.53 folds and 1.7 folds in the simple hypoxia group respectively,and caspasse-3 mRNA expression decreased by 70％ (all at P ＜ 0.05).Under the normoxia condition,the expression of bcl-2 and pro-caspase-3 protein in the cells were not significantly different among the various groups (P＞0.05),however,the expressions of bcl-2 and pro-caspase-3 proteins were elevated by 1.6 folds and 1.9 folds in the hypoxia group in compared with the normoxia group (P＜0.05).Compared with the simple hypoxia group,the expressions of bcl-2 and pro-caspase-3 were lowed by 40.4％ and 42.5％ in the 5.0 μmol/L 15-HETE group (P＜0.05).Conclusions 15-HETE inhibits the proliferation of RMVECs and therefore suppresses neovascularization by down-regulating the expressions of HIF-1α and bcl-2 and the activation of caspase-3 in a dose-dependent manner.

Identification and characterization of novel alternative splice variants of human SAMD11.

Sterile alpha motif domain-containing 11 (SAMD11) is evolutionarily conserved from zebrafish to human. Mouse Samd11 is predominantly expressed in developing retinal photoreceptors and the adult pineal gland, and its transcription is directly regulated by the cone-rod homeodomain protein Crx. However, there has been little research on human SAMD11. To investigate the function of human SAMD11, we first cloned its coding sequence (CDS) and identified up to 45 novel alternative splice variants (ASVs). Mouse Samd11 ASVs were also identified by aligning the mouse Samd11 expressed sequence tags (ESTs) with the annotated sequence. However, the range of expression and transcriptional regulation of SAMD11 differs between human and mouse. Human SAMD11 was found to be widely expressed in many cell lines and ocular tissues and its transcription was not regulated by CRX, OTX2 or NR2E3 proteins. Furthermore, functional analysis indicated that human SAMD11 could promote cell proliferation slightly. In conclusion, this study elucidated the basic characteristics of human SAMD11 and revealed that, although the occurrence of alternative splicing of SAMD11 was conserved, the function of SAMD11 may vary in different species.

A novel method for culture and identification of primary human retinal microvascular endothelial cells / 中华实验眼科杂志

Background To optimize the culture method of human retinal microvascular endothelial cells is very important for the study of retinal angiogenesis disease.Human retinal microvascular endothelial cells have been successfully cultured in previous studies,but further improvement of the culture method to harvest higher yields and purity cells is still needed.Objective This study was to design a modified method to isolate and purify human retinal microvascular endothelial cells much easily and quickly,and to compare the expression of specific markers of vascular endothelial cells,factor Ⅷ and CD31/CD34 in the cells.Methods The use of human donor eyeballs was approved by the Ethic Commission of Zhongshan Ophthalmic Center of Sun Yat-sen University.The retina tissue from healthy donor was isolated and digested by the two-step digestion method with 2％ trypsin and 0.133％ collagenase Ⅳ.Human retinal microvascular endothelial cells were collected and plated in 60 mm dishes coated by 0.1％ fibronectin and cultured in endothelial cell-specialized medium supplemented with 10％ fetal bovine serum,0.3 mg/L β-endothelial cell growth factor (ECGF) and 100 ng/L sodium heparin.During the culturing,the growth situation of the cells was monitored by morphological observation,and immunohistochemical staining was performed to probe vascular endothelial cell-specific membrane protein CD31,CD34 and factor Ⅷ for identification of the cell purity.Results Human retinal microvascular endothelial cells were isolated successfully from the retina by the twostep digestion method.The primary cultured cells adhered to well 72 hours later and achieved confluence with the typical cobblestone appearance 9 to 10 days after cultured.The cells exhibited the blue nuclei and reddish cytoplasm by regular haematoxylin and eosin stain and showed a strong positive response for CD31,CD34 and factor Ⅷ by immunohistochemistry.The positive dye of CD31 and CD34 was lower than Ⅷ factor in both endothelial cells.Conclusions Modified culture method of human retinal microvascular endothelial cells can improve cell culture result and purify target cells.

Effects of static pressure on the expression of ET-1 and NO in cultured retinal microvascular endothelial cells / 眼科研究

Background Researches have demonstrated that ocular hypertension induces the ischemia-reperfusion of retina and further leads to the degeneration of retinal ganglion cells,but its mechanism is beyond understanding.Objective The present study aims to observe the effects of static pressure on the morphology,proliferation activity and viability of cultured retinal microvascular endothelial cells (RMECs) and evaluate the expression of ET-1 and NO in these cells under variant static pressure.Methods RMECs were isolated from 30 healthy Wistar rats and cultured using explant culture method by Ⅷ factor antibody and PECAM-1 antibody.The static pressure of 1.33kPa,2.67kPa,5.33kPa and 10.67kPa was used in culture bottle respectively.The RMECs without static pressure were used as normal control group.The morphology of RMECs under the different static pressure was observed by inverted phase contrast microscopy,and the number of RMECs was counted using the counting plate.Cellular viability was studied by trypan blue staining.The changes of ET-1 and NO_2~-/NO_3~-,two metabolic products of NO,in the medium were detected by radioimmunoassay and Griess's nitrate reductase method.The expression of ET-1,eNOS and iNOS mRNA in RMECs was analyzed by semi-quantitative RT-PCR 24 hours after treatment of variant static pressure.Results Cultured RMECs sticked well at 24 hours and reached to confluence at 48 hours and showed the red fluorescence for Ⅷ factor antibody and PECAM-1 antibody.Enlargement of nuclei,extenders of cell bodies and suspension of RMECs in medium were observed.The number of RMECs was gradually increased.The cell viability was reduced with the raise of static pressure among these four groups(F=12.205,P＜0.01;F=11.180,P＜0.01).The static pressure increased the content of ET-1 released by RMECs in 2.67kPa,5.33kPa and 10.67kPa of static pressure groups,and concentrations of NO_2~-/NO_3~- in the medium showed a significant increase in 5.33kPa and 10.67kPa of static pressure groups compared with normal and 1.33kPa of static pressure groups(P＜0.01).The expressions of ET-1 mRNA,eNOS mRNA and iNOS mRNA were considerably enhanced in 5.33kPa and 10.67kPa of static pressure groups compared with normal control group(P＜0.01).Conclusion Raised static pressure causes the alteration of RMGCs structure and morphology.Static pressure could upregulate the expressions of ET-1,eNOS and iNOS mRNA in RMECs and increase the release of ET-1 and NO.This pathway might be one of pathologic mechanisms of retinal injury induced by high intraocular pressure.