Objective To investigate the role and relative mechanism of stromal cell derived factorl (SDF-1) secreted by nucleus pulposus cells (NPCs) on the proliferation of vascular endothelial cells (VECs). Methods The NPCs were isolated from the degenerated disc specimens after discectomy. NPCs at passage 1 were transfected with lentivirus-mediated SDF-1 over-expression; transfected and untransfected NPCs at passage 2 were cultured in the three-dimensional alvetex® scaffold, then they were co-cultured with HMEC-1 cells. The morphology of NPCs was observed by scanning electron microscope (SEM), and the apoptosis of HMEC-1 cells was detected by Annexin V/propidiumiodide staining after 72 hours co-culutre. The proliferation of HMEC-1 cells was detected by cell counting kit 8 at 12, 24, 48, and 72 hours in transfected group and untransfected group, respectively. ELISA was used to measure the vascular endothelial growth factor (VEGF) expression level. The virus transfection efficiency and relative Akt pathway were determined by Western blot. Results The NPCs maintained cell phenotype and secreted much extracellular matrix in three-dimensional-culture by SEM observation. In the co-culutre system, after NPCs were transfected with SDF-1 over-expression lentivirus, the proliferation of HMEC-1 cells was significantly increased, while the apoptosis was decreased obviously. The ELISA results demonstrated that the amount of VEGF was remarkably increased in the culture medium. Furthermore, SDF-1 promoted the up-regulation of phosphorylate Akt expression; after inhibition of Akt expression by GSK690693, the proliferation rate of VECs decreased significantly. Conclusion Over-expression of SDF-1 by NPCs is beneficial for VECs proliferation, which is involved in SDF-1-Akt signalling pathway.
ObjectiveTo observe the effects of NDRG1 on proliferation, migration and lumen formation of retinal vascular endothelial cells (RF/6A cells) in monkeys under high glucose condition. MethodsRF/6A cells were divided into normal group, mannitol group, high glucose group, small interfering RNA (siRNA) negative control group without target gene (siRNA group), 30 nmol/L siRNA down-regulated NDRG1 genome (siNDRG1 group) and 50 nmol/L siNDRG1 group. Normal group cells were cultured conventionally. The mannitol group was added with 25 mmol/L mannitol, and the high-glucose group was added with 25 mmol/L glucose. In the siRNA group, 25 mmol/L glucose was added, and then blank siRNA was added for induction. The 30 and 50 nmol/L siNDRG1 groups were added with 25 mmol/L glucose and induced with 30 and 50 nmol/L siRNDRG1, respectively. All cells were incubated for 24 h for follow-up experiments. Cell proliferation was observed by 4', 6-diaminidine 2-phenylindole staining. Cell counting kit-8 staining was used to detect cell activity. The expression level of NDRG1 mRNA and protein was detected by Western blot and real-time quantitative polymerase chain reaction. Cell migration was observed by cell scratch assay. Cell lumen formation assay was used to detect lumen formation. The two-tailed Student t test was used to compare the two groups. One-way analysis of variance was used to compare groups. ResultsThere were significant differences in cell proliferation rate (t=36.659, 57.645) mobility rate (t=24.745, 33.638) and lumen formation number (t=41.276, 22.867) between high glucose group and normal group and mannitol group (P＜0.01). Compared with normal group and mannitol group, the relative expression levels of NDRG1gene mRNA and protein in high glucose group were significantly decreased, with statistical significance (t=46.145, 21.541, 36.738, 32.976; P＜0.001). Compared with the siRNA negative group, the relative expression levels of NDRG1gene mRNA and protein in 30 nmol/L siNDRG1 group and 50 nmol/L siNDRG1 group were significantly decreased, and the differences were statistically significant (t=44.275, 40.7577, 57.167, 25.877; P＜0.01). Compared with normal group and siRNA group, cell mobility in 30 nmol/LsiNDRG1 group was increased, and the difference was statistically significant (t=57.562, 49.522; P＜0.01). Compared with normal group and siRNA group, the number of cell lumen formation in 30 nmol/LsiNDRG1 group was significantly increased in the same field of vision, and the difference was statistically significant (t=63.446, 42.742; P＜0.01). ConclusionDown-regulation of NDRG1 gene can improve the activity, migration and lumen formation of RF/6A cells under hyperglycemia.
Objective To explore the effect of natural hirudin on proliferation of human microvascular endothelial cells (HMVECs) and its preliminary mechanism of promoting angiogenesis. Methods Three-dimensional culture models of HMVECs were established in vitro and observed by inverted phase contrast microscopy after 24 hours of culturing. Then, the three-dimensional culture models of HMVECs were treated with different concentrations (1, 4, and 7 ATU/mL) of the natural hirudin, respectively, and Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum as control. The cell proliferations of 4 groups were detected by cell counting kit 8 (CCK-8) method at 24, 48, and 72 hours; the angiogenesis of 4 groups were observed by tube formation assay at 24 hours; the expressions of vascular endothelial growth factor (VEGF) and Notch1 of HMVECs in 4 groups were observed by immunofluorescence staining at 24 hours. Results The observation of cells in three-dimensional culture models showed that HMVECs attached to Matrigel well, and the cells formed tube structure completely after 24 hours. The results of CCK-8 test showed that the absorbance (A) value of 1 and 4 ATU/mL groups were higher than that of control group at each time point (P<0.05), andA value of 4 ATU/mL group was the highest. The A value of 7 ATU/mL group was significantly lower than those of 1 and 4 ATU/mL groups and control group (P<0.05). The tube formation assay showed that the tube structure was more in 1 and 4 ATU/mL groups than in 7 ATU/mL group and control group, and in 4 ATU/mL group than in 1 ATU/mL group, showing significant differences (P<0.05). There was no significant difference between 7 ATU/mL group and control group (P>0.05). The results of immunofluorescence staining showed that compared with control group, the Notch1 expression was higher in 1 and 4 ATU/mL groups and lower in 7 ATU/mL group; and there was significant difference between 4 and 7 ATU/mL groups and control group (P<0.05). The VEGF expression was higher in 1, 4, and 7 ATU/mL groups than in control group, in 4 ATU/mL group than in 1 and 7 ATU/mL groups, showing significant differences (P<0.05). Conclusion Natural hirudin can promote angiogenesis at low and medium concentrations, but suppress angiogenesis at high concentrations. Its mechanism may be related to the VEGF-Notch signal pathway.
ObjectiveTo explore the effect of Kaempferol on bone microvascular endothelial cells (BMECs) in glucocorticoid induced osteonecrosis of the femoral head (GIONFH) in vitro. MethodsBMECs were isolated from cancellous bone of femoral head or femoral neck donated voluntarily by patients with femoral neck fracture. BMECs were identified by von Willebrand factor and CD31 immunofluorescence staining and tube formation assay. The cell counting kit 8 (CCK-8) assay was used to screen the optimal concentration and the time point of dexamethasone (Dex) to inhibit the cell activity and the optimal concentration of Kaempferol to improve the inhibition of Dex. Then the BMECs were divided into 4 groups, namely, the cell group (group A), the cells treated with optimal concentration of Dex group (group B), the cells treated with optimal concentration of Dex+1 μmol/L Kaempferol group (group C), and the cells treated with optimal concentration of Dex+5 μmol/L Kaempferol group (group D). EdU assay, in vitro tube formation assay, TUNEL staining assay, Annexin Ⅴ/propidium iodide (PI) staining assay, Transwell migration assay, scratch healing assay, and Western blot assay were used to detect the effect of Kaempferol on the proliferation, tube formation, apoptosis, migration, and protein expression of BMECs treated with Dex. ResultsThe cultured cells were identified as BMECs. CCK-8 assay showed that the optimal concentration and the time point of Dex to inhibit cell activity was 300 μmol/L for 24 hours, and the optimal concentration of Kaempferol to improve the inhibitory activity of Dex was 1 μmol/L. EdU and tube formation assays showed that the cell proliferation rate, tube length, and number of branch points were significantly lower in groups B-D than in group A, and in groups B and D than in group C (P<0.05). TUNEL and Annexin V/PI staining assays showed that the rates of TUNEL positive cells and apoptotic cells were significantly higher in groups B-D than in group A, and in groups B and D than in group C (P<0.05). Scratch healing assay and Transwell migration assay showed that the scratch healing rate and the number of migration cells were significantly lower in groups B-D than in group A, and in groups B and D than in group C (P<0.05). Western blot assay demonstrated that the relative expressions of Cleaved Caspase-3 and Bax proteins were significantly higher in groups B-D than in group A, and in groups B and D than in group C (P<0.05); the relative expressions of matrix metalloproteinase 2, Cyclin D1, Cyclin E1, VEGFA, and Bcl2 proteins were significantly lower in groups B-D than in group A, and in groups B and D than in group C (P<0.05). Conclusion Kaempferol can alleviate the damage and dysfunction of BMECs in GIONFH.
To study the potential molecular mechanism of tumor angiogenesis in its microenvironment, we investigated the effects of HepG2 conditioned medium on the proliferation of vascular endothelial cell and vascular angiogenesis in our laboratory. Human umbilical vein endothelial EA.hy926 cells were co-cultured with HepG2 conditioned medium in vitro. The proliferation and the tubulogenesis of EA.hy926 cells were detected by teramethylazo salt azole (MTT) and tube formation assay, respectively. The results showed that the survival rate of the EA.hy926 cells was significantly increased under the co-culture condition. HepG2 conditioned medium also enhanced the angiogenesis ability of EA.hy926 cells. In addition, the expressions of intracellular VEGF and extracellular VEGFR (Flk-1) were regulated upward in a time-dependent manner. In conclusion, the proliferation of vascular endothelial cells and Vascula angiogenesis were improved under the condition of indirect co-culture.
Objective To observe the effect of metformin (Met) on inflammatory bodies and focal death in human retinal microvascular endothelial cells (hRMEC) in diabetes mellitus (DM) microenvironment. MethodsExperimental research was divided into in vivo animal experiment and in vitro cell experiment. In vivo animal experiments: 9 healthy C57BL/6J male mice were randomly divided into DM group, normal control group, and DM+Met group, with 3 mice in each group. DM group and DM+Met group mice were induced by streptozotocin to establish DM model, and DM+Met group was given Met 400 mg/ (kg · d) intervention. Eight weeks after modeling, the expression of NLRP3, cleaved-membrane perforating protein D (GSDMD) and cleaved-Caspase-1 in the retina of mice in the normal control group, DM group and DM+Met group were observed by immunohistochemical staining. In vitro cell experiments: hRMEC was divided into conventional culture cell group (N group), advanced glycation end products (AGE) group, and AGE+Met group. Joining the AGE, AGE+Met groups cells were induced by 150 μg/ml of glycation end products, and 2.0 mmol/L Met was added to the AGE+Met group. Pyroptosis was detected by flow cytometry; 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe was used to detect the expression of reactive oxygen species (ROS) in cells of each group. Real-time fluorescence quantitative polymerase chain reaction and Western blot were used to detect the relative mRNA and protein expression levels of NLRP3, cleaved-GSDMD, cleaved-Caspase-1 in each group of cells. Single factor analysis of variance was used for comparison among the three groups. ResultsIn vivo animal experiments: compared with the DM group, the expression of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in the retina of normal control group and DM+Met group mice was significantly reduced, with significant difference among the 3 groups (F=43.478, 36.643, 24.464; P＜0.01). In vitro cell experiment and flow cytometry showed that the pyroptosis rate of AGE group was significantly higher than that of N group and AGE+Met group (F=32.598, P＜0.01). The DCFH-DA detection results showed that the intracellular ROS levels in the N group and AGE+Met group were significantly lower than those in the AGE group, with the significant difference (F=47.267, P＜0.01). The mRNA (F=51.563, 32.192, 44.473; P＜0.01) and protein levels (F=63.372, 54.463, 48.412; P＜0.01) of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in hRMEC of the AGE+Met group were significantly reduced compared to the N group. ConclusionMet can down regulate the expression of NLRP3 inflammatory body related factors in hRMEC and inhibit pyroptosis.
ObjectiveTo evaluate the effects of icariin on autophagy induced by low-concentration of glucocorticoid and exosome production in bone microvascular endothelial cells (BMECs).MethodsBMECs were isolated from femoral heads resected in total hip arthroplasty and then intervened with hydrocortisone of low concentration (0, 0.03, 0.06, 0.10 mg/mL), which were set as groups A, B, C, and D, respectively. On the basis of hydrocortisone intervention, 5×10−5 mol/L of icariin was added to each group (set as groups A1, B1, C1 and D1, respectively). Western blot was used to detect the expressions of microtubule-associated protein 1 light chain 3B (LC3B) and dead bone slice 1 (p62) after 24 hours. Exosomes were extracted from BMECs treated with icariin (intervention group) and without icariin (non-intervention group), and the diameter and concentration of exosomes were evaluated by nanoparticle tracking analysis technique. The total protein content of exosomes was detected by BCA method, and the expressions of proteins carried by exosomes including CD9, CD81, transforming growth factor β1 (TGF-β1), and vascular endothelial growth factor A (VEGFA) were assessed by Western blot. The BMECs were further divided into three groups: BMECs in the experimental group and the control group were co-cultured with exosomes secreted by BMECs treated with or without icariin, respectively; the blank control group was BMECs without exosome intervention. The three groups were treated with hydrocortisone and Western blot was used to detect the expressions of LC3B and p62. The scratching assay was used to detect cell migration ability; angiogenic ability of BMECs was also assessed.ResultsWith the increase of hydrocortisone concentration, the protein expression of LC3B-Ⅱ increased gradually, and the protein expression of p62 decreased gradually (P<0.01). Compared with group with same concentration of hydrocortisone, the protein expression of LC3B-Ⅱ decreased and the protein expression of p62 increased after the administration of icariin (P<0.01). The concentration of exosomes in the intervention group was significantly higher than that in the non-intervention group (t=−10.191, P=0.001); and there was no significant difference in exosome diameter and total protein content between the two groups (P>0.05). CD9 and CD81 proteins were highly expressed in the non-intervention group and the intervention group, and the relative expression ratios of VEGFA/CD9 and TGF-β1/CD9 proteins in the intervention group were significantly higher than those in the non-intervention group (P<0.01). After co-culture of exosomes, the protein expression of p62 increased in blank control group, control group, and experimental group, while the protein expression of LC3B-Ⅱ decreased. There were significant differences among groups (P<0.05). When treated with hydrocortisone for 12 and 24 hours, the scratch closure rate of the control group and experimental group was significantly higher than that of the blank control group (P<0.05), and the scratch closure rate of the experimental group was significantly higher than that of the control group (P<0.05). When treated with hydrocortisone for 4 and 8 hours, the number of lumens, number of sprouting vessels, and length of tubule branches in the experimental group and the control group were significantly greater than those in the blank control group (P<0.05); the length of tubule branches and the number of lumens in the experimental group were significantly greater than those in the control group (P<0.05).ConclusionIcariin and BMECs-derived exosomes can improve the autophagy of BMECs induced by low concentration of glucocorticoid.
Objective To study the effect of silencing the NOD-like receptor family, pyrin domain containing protein 3 (NLRP3) gene on the production of inflammatory factors induced by lipopolysaccharide (LPS) and adenosine triphosphate (ATP) in rat brain microvascular endothelial cells (BMECs), and whether NLRP3 inflammasome signaling pathway plays a role in the BMEC model of cerebral small vessel disease induced by proinflammatory agents. Methods BMECs from male Wistar rats were extracted in vitro and the morphology and purity of endothelial cells were identified. BMECs in normal culture were divided into blank control group and LPS+ATP group. The expression levels of NLRP3 inflammasome and downstream inflammatory factor Caspase-1 were detected by Western blot and real-time polymerase chain reaction, and compared by student’s t test between the two groups. Small interfering RNA (siRNA) was used to silence the specific gene NLRP3 in BMECs. After transfection of siRNA NLRP3 and siRNA plasmid negative control into BMECs, the transfected cells were divided into four groups, namely, siNC group (non silenced target gene), siNLRP3 group (silenced target gene), siNC+LPS+ATP group (non silenced target gene and added proinflammatory agents) and siNLRP3+LPS+ATP group (silenced target gene and added proinflammatory agents). The expression levels of NLRP3 and Caspase-1 were detected by Western blot and real-time polymerase chain reaction, and analyzed by analysis of variance for 2-factor factorial design. Results The microvascular segments of rat BMECs were “beaded” after 24 h of isolation and culture; after 48 h, “island” cell clusters were formed; after 72 h, “paving stone” like monolayer cells adhered to the wall and grew. After that, the cells gradually became dense and reached the convergence degree of 80%. The positive rate of BMECs detected by immunofluorescence staining was 96%. In the normally cultured cells, the protein and mRNA expression levels of NLRP3 and Caspase-1 in the LPS+ATP group were higher than those in the blank control group (P<0.05). In the RNA interference cultured cells, the protein and mRNA expression levels of NLRP3 and Caspase-1 in the siNLRP3 group were lower than those in the siNC group, and those expression levels in the siNLRP3+LPS+ATP group were lower than those in the siNC+LPS+ATP group (P<0.05); the protein and mRNA expression levels of NLRP3 and Caspase-1 in the siNC+LPS+ATP group were higher than those in the siNC group, and those expression levels in the siNLRP3+LPS+ATP group were higher than those in the siNLRP3 group (P<0.05). Plasmid transfection and proinflammatory agents intervention had statistically significant interaction effect on the mRNA expression of NLRP3 and Caspase-1 (P<0.05). Conclusions LPS and ATP can promote the release of NLRP3 and Caspase-1 in BMECs. Silencing NLRP3 gene expression can reduce the induction of proinflammatory agents. NLRP3 inflammasome signaling pathway may play a role in the cerebral small vessel disease cell model of rat BMECs induced by proinflammatory agents.
ObjectiveTo observe the effects of four prostaglandin E2 (PGE2) receptors (EP1-4R) on the activation of inflammasomes and cell damage in human retinal microvascular endothelial cells (hRMEC) in a high glucose environment.MethodsThe hRMEC were divided into normal group and high glucose group, and they were cultured in Dulbecco modified Eagle medium containing 5.5 and 30.0 mmol/L glucose, respectively. Flow cytometry was used to observe the apoptosis rate of the high glucose group and the normal group; enzyme chain immunosorbent assay (ELISA) was used to detect the level of PGE2 in the culture supernatant of hRMEC cells. Western blot was used to detect the protein expression of cyclooxyganese (COX2) and EP1-4R in hRMEC. Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of EP1-4R mRNA in hRMEC. After 72 h of culture, the cells in the high glucose group were divided into control group, PGE2 group, EP1-4R agonist group, PGE2+EP1-4R inhibitor group, and dimethylsulfoxide group. According to the group, each group was given the corresponding agonist or inhibitor to continue the culture for 24 h. QRT-PCR was used to detect the expression of nucleotide-binding oligomerization structure-like receptor protein (NLRP3) and pro-interleukin (IL)-1β mRNA in each group of cells. ELISA was used to detect the content of IL-1β and lactic dehydrogenase (LDH) in the cell culture supernatant. Western blot was used to detect the expression of cleaved Caspase-1 in each group of cells. At the same time, hRMEC in a high glucose environment was given IL-1β stimulation for 24 h, and the activity of LDH in the supernatant of the cell culture medium was detected.ResultsThe apoptotic rate, COX2 protein expression, and PGE2 protein content in hRMEC in the high glucose group were significantly higher than those in the normal group, and they were time-dependent. Compared with the normal group, the expression levels of EP1R, EP2R, EP4R protein and mRNA in hRMEC in the high glucose group were higher than those in the normal group (P＜0.05). Compared with the control group, PGE2 group (t=4.627, P＜0.01), EP1-4R agonist group (t=3.889, 3.583, 2.445, 3.216; P＜0.05) hRMEC NLRP3 mRNA expression level was significantly increased; the expression level of pro-IL-1β mRNA increased, however the difference was not statistically significant (PGE2 group: t=1.807, P＞0.05; EP1-4R agonist group: t=1.807, 1.477, 0.302, 1.926, P＞0.05). Compared with the PGE2 group, the expression of NLRP3 mRNA in hRMEC in the PGE2+EP2R inhibitor group was significantly reduced (t=2.812, P＜0.05); the expression of pro-IL-1β mRNA in hRMEC in the PGE2+EP3R inhibitor group was significantly increased (t=4.113, P＜0.01). The protein content of IL-1β in the cell culture supernatant of the PGE2 group, EP1R agonist group and EP2R agonist group was significantly higher than that of the control group (t=5.155, 4.136, 4.817; P＜0.01). Compared with PGE2 group, the protein content of IL-1β in the cell culture supernatant of the PGE2+EP2R inhibitor group and the PGE2+EP4R inhibitor group were significantly lower than that of the PGE2 group (t=1.964, 4.765; P＜0.05). The expression of cleaved Caspase-1 in hRMEC in the PGE2 group and EP2R agonist group was significantly higher than that in the control group (t=5.332, 4.889; P＜0.05). The expression of cleaved Caspase-1 in hRMEC in the PGE2+EP2R inhibitor group was significantly lower than that of the PGE2 group (t=6.699, P＜0.01). The LDH activity in the cell culture supernatant of the PGE2 group and the EP2R agonist group was significantly higher than that of the control group (t=4.908, 4.225; P＜0.05). The activity of LDH in the cell culture supernatant of the PGE2+EP2R inhibitor group was significantly lower than that of the PGE2 group (t=5.301, P＜0.01). Compared with the control group, the LDH activity in the culture supernatant of hRMEC cells in the high glucose environment was significantly increased (t=3.499, P＜0.05).ConclusionsThe four receptors of PGE2 can activate NLRP3 and its effector molecules to varying degrees. EP2R mainly mediates hRMEC damage under high glucose environment.
Coronary atherosclerotic heart disease is a serious threat to human life and health. In recent years, the main treatment for it is to implant the intravascular stent into the lesion to support blood vessels and reconstruct blood supply. However, a large number of experimental results showed that mechanical injury and anti-proliferative drugs caused great damage after stent implantation, and increased in-stent restenosis and late thrombosis risk. Thus, maintaining the integrity and normal function of the endothelium can significantly reduce the rate of thrombosis and restenosis. Stem cell mobilization, homing, differentiation and proliferation are the main mechanisms of endothelial repair after vascular stent implantation. Vascular factor and mechanical microenvironmental changes in implanted sites have a certain effect on re-endothelialization. In this paper, the process of injury caused by stent implantation, the repair mechanism after injury and its influencing factors are expounded in detail. And repairing strategies are analyzed and summarized. This review provides a reference for overcoming the in-stent restenosis, endothelialization delay and late thrombosis during the interventional treatment, as well as for designing drug-eluting and biodegradation stents.