ObjectiveTo observe the effect of exosomes derived from human umbilical cord blood mesenchymal stem cells (hUCMSC) on the expression of vascular endothelial growth factor (VEGF) A in blue light injured human retinal pigment epithelial (RPE) cells. MethodshUCMSC were cultured with exo-free fetal bovine serum for 48 hours, and then the supernatants were collected to isolate and purify exosomes by gradient ultracentrifugation method. Transmission electron microscopy was used to identify the morphology of exosomes. Surface specific maker protein CD63 and CD90 were detected via Western blot. Cultured ARPE-19 cells were divided into normal control group, blue light injured group and hUCMSC exosomes treated group. Cells were exposed to the blue light at the intensity of (2000±500) Lux for 12 hours to establish the light injured models. The cells of hUCMSC exosomes treated group were treated by different concentrations of exosomes for 8, 16, 24 hours. The mRNA and protein of VEGF-A were determined by real time-polymerase chain reaction and Western blot. Immunofluorescence assay were used to detect the expression levels of VEGF-A. ResultshUCMSC exosomes were successfully isolated, they exhibited round or oval shape and their diameter ranged from 50 to 100 nm with membrane structure through electron microscope. hUCMSC exosomes expressed the common surface marker protein CD63 and the surface marker protein CD90 of hUCMSC. The protein and mRNA level of VEGF A in the blue light injured group increased significantly compared to that in normal control group (t=-16.553, -19.456; P < 0.05). After treating with low, middle and high concentration of hUCMSC exosomes for 8, 16 and 24 hours, the protein and mRNA level of VEGF A of injured RPE were significantly decreased (P < 0.05). With the treated time and concentration of hUCMSC exosomes improved, the protein and mRNA level of VEGF A of injured RPE gradually decreased (P < 0.05). Immunofluorescence assay showed the protein level of VEGF-A of injured RPE gradually decreased with the same concentration of hUCMSC exosomes treated over time. ConclusionhUCMSC exosomes can effectively down-regulate the mRNA and protein level of VEGF-A in blue light injured RPE, the effect depends on the concentration and treated time of hUCMSC exosomes.
ObjectiveTo observe the immunological regulation effects of human umbilical cord mesenchymal stem cells (hUCMSC) on glucose-damaged rhesus retinal vascular endothelial cells (RF/6A). MethodshUCMSC and RF/6A were co-culture according to 1:1 ratio in the co-culture system (Transwell plates), hUCMSC cells were added to upper chamber, while the lower chamber containing 25mmol/L glucose and RF/6A. There were three groups including RF/6A blank control group, high glucose treated RF/6A group, and high glucose treated RF/6A with hUCMSC co-culture group. MTT was used to measure the RF/6A cell viability. Western blot was used to to detect protein level of Foxp3. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of interleukin (IL)-17. ResultsMTT assay revealed that at the first day, the survival rate of the three groups had no significant difference (F=0.030, P > 0.05). On day 3 and day 7, the cell viability of the high glucose group was significantly lower than that of the control group (t=36.072, 27.890; P < 0.05), the cell viability of the high glucose treated RF/6A with hUCMSC co-culture group was higher than that of high glucose group (t=36.072, 19.650; P < 0.05).Western blot analysis showed that Foxp3 in high glucose RF/6A group was significantly lower than that in the control group at day 7 after culture (t=7.826, P < 0.05) and high glucose RF/6A with hUCMSC group (t=19.936, P < 0.05). ELISA showed that IL-17 in the high glucose group, high glucose with hUCMSC co-culture group was significantly higher than that of the control group (F=1 267.503, P < 0.05), while IL-17 in the hUCMSC co-culture group was significantly lower than that in high glucose group (t=17.386, P < 0.05). ConclusionhUCMSC can regulate the expression of Foxp3 and IL-17 to increase the proliferative ability of RF/6A, which was suppressed by high glucose.
Objective To investigate the effects of exosomes from cultured human retinal pigment epithelium (ARPE-19) cells affected by oxidative stress on the proliferation and expression of vascular endothelial growth factor-A (VEGF-A) and Akt of ARPE-19 cells. Methods Culture ARPE-19 cells. The concentration of 2.5 μmol/L rotenone was selected to simulate oxidative stress and isolated ARPE-19-exosome. Exosomes were isolated by ExoQuick exosome precipitation solution. Transmission electron microscopy was used to identify the morphology of exosomes. Western blot was used to detect exosomes’ surface-specific maker protein CD63. ARPE-19 cells affected by oxidative stress were cultured with exosome as experimental group, normal ARPE-19 cells were cultured with exosome as control group. The cell proliferation was examined by methyl thiazolyl tetrazolium assay. Western blot and immunofluorescence assay were used to detect the expression levels of VEGF-A and Akt protein. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the levels of VEGF-A mRNA and Akt mRNA. Results The diameter of normal ARPE-19-exosomes ranged from 50 to 150 nm. The isolated exosomes expressed CD63. AREP-19 cells were cultured with ARPE-19 (affected by rotenone)-exosome, the cell viability in experimental group was significantly reduced than in the control group. Green fluorescence was observed in the cytoplasm under fluorescence microscope. Compared with the control group, VEGF-A was up-regulated expressed and Akt was down-regulated expressed. Western blot results showed that, VEGF-A protein expression in the experimental group were higher than the control group. Akt protein expression in the experimental group were less than the control group. The difference was statically significant (t=3.822, 6.527;P＜0.05). RT-PCR results showed that VEGF-A mRNA expression levels was higher in the experimental group than the control group. Akt mRNA expression levels was lower in the experimental group than the control group. The difference was statically significant (t=8.805, −7.823;P＜0.05). Conclusions Exosomes from ARPE-19 cells affected by oxidative stress inhibit the proliferation of normal ARPE-19 cells, increase the expression of VEGF-A and reduce the expression of Akt.