OBJECTIVE: To explore the molecular mechanisms of Porphyromonas gingivalis infection-induced umbilical vein endothelial barrier dysfunction in vitro. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured in vitro, and after the formation of the endothelial barrier, the cells were infected with P. gingivals at a multiplicity of infection (MOI). The transepithelial electrical resistance (TEER) of the cell barrier was measured, and FITC-dextran trans-endothelial permeability assay and bacterial translocation assay were performed to assess the endothelial barrier function. The expression levels of cell junction proteins including ZO-1, occludin and VE-cadherin in the cells were examined by qRT-PCR and Western blotting. RESULTS: In freshly seeded HUVECs, TEER increased until reaching the maximum on Day 5 (94 Ωcm²), suggesting the formation of the endothelial barrier. P. gingivals infection caused an increase of the permeability of the endothelial barrier as early as 0.5 h after bacterial inoculation, and the barrier function further exacerbated with time, as shown by significantly lowered TEER, increased permeability of FITC-dextran (40 000/70 000), and increased translocation of SYTO9-E. coli cross the barrier. MTT assay suggested that P. gingivals infection did not significantly affect the proliferation of HUVECs (P>0.05), but in P. gingivalsinfected cells, the expressions of ZO-1, occludin and VE-cadherin increased significantly at 24 and 48 h after bacterial inoculation (P < 0.05). CONCLUSION P. gingivals may disrupt the endothelial barrier function by down-regulating the expressions of the cell junction proteins (ZO-1, occludin, VE-cadherin) and increasing the permeability of the endothelial barrier.
Humans ; Cadherins/metabolism* ; Escherichia coli/metabolism* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Occludin ; Porphyromonas gingivalis/metabolism* ; Umbilical Veins/metabolism*

The expression of endothelial nitric oxide synthase traffic inducer (NOSTRIN) was examined in the umbilical vessels of the patients with pre-eclampsia (PE) to explore its possible role in the pathogenesis of PE. The NOSTRIN mRNA in umbilical tissues was determined by RT-PCR. The eNOS activity in umbilical vessels was spectrophotometrically detected. NO2-/NO3-, the stable metabolic end products of NO, was measured by using nitrate reductase. RT-PCR showed that the expression level of NOSTRIN was significantly higher in women with PE than in the normal group (P<0.01). The activity of eNOS was significantly decreased in PE group [(12.83+/-3.61) U/mg] than in normal group [(21.72+/-3.83) U/mg] (P<0.01). The level of NO2-/NO3- in PE patients (27.53+/-7.48) micromol/mg was significantly lower than that of normal group (54.27+/-9.53) micromol/mg (P<0.01). The significant negative correlation existed between the expression of NOSTRIN and the activity of eNOS in umbilical vessels of women with PE (r=-0.58, P<0.01). It was concluded that the level of NOSTRIN expression was increased in umbilical vessel of women with PE, indicating that it may be involved in the pathogenesis of PE.
Intracellular Signaling Peptides and Proteins/genetics ; Intracellular Signaling Peptides and Proteins/*metabolism ; Pre-Eclampsia/*enzymology ; Pre-Eclampsia/etiology ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; Umbilical Arteries/cytology ; Umbilical Arteries/*enzymology ; Umbilical Veins/cytology ; Umbilical Veins/*enzymology

OBJECTIVETo investigate the effects of tumor necrosis factor-alpha(TNF-alpha) on syndecan-4 protein expression and proliferation of cultured human umbilical vein endothelial-like cells (HUVECs) in vitro.

METHODSHUVECs exposed to different concentrations of TNF-alpha(100, 20, 10, and 1 ng/ml) were cultured for 24 h and 36 h to observe their proliferation in comparison with the control group. The cell proliferation rate was determined by non-radioactive MTS/PES assay. The expression of syndecan-4 protein was evaluated by immunoblotting technique using anti-syndecan-4 antibody. Results The proliferation rate of the endothelial-like cells was 1.956-/+0.214 in the control group, and 2.154-/+0.250, 2.260-/+0.151, 2.118-/+0.205 and 2.106-/+0.136 in TNF-alpha-treated groups corresponding to TNF-alpha concentrations of 100, 20, 10 and 1 ng/ml at 24 h, respectively. It was shown that TNF-alpha significantly stimulated cell proliferation at the concentration above 1 ng/ml (P<0.05) as compared with the control group (P<0.05). The proliferation rate of the endothelial-like cell was 1.915-/+0.236 in the control group, and 2.067-/+0.328, 2.207-/+0.150, 2.052-/+0.126 and 2.051-/+0.180 in TNF-alpha-treated groups corresponding to TNF-alphaconcentrations of 100, 20, 10 and 1 ng/ml at 36 h, respectively. The expression of syndecan-4 protein was significantly enhanced by TNF-alpha.

CONCLUSIONSTNF-alpha can stimulate HUVEC proliferation, and expression of syndean-4 may represent an additional component of the pro-inflammatory, growth-stimulating pathways that are activated in response to changes in the vascular wall.

Cell Proliferation ; Cells, Cultured ; Endothelial Cells ; metabolism ; Humans ; Syndecan-4 ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology ; Umbilical Veins ; cytology

Cells, Cultured ; Endothelial Cells ; drug effects ; metabolism ; Endothelium, Vascular ; cytology ; metabolism ; Gene Expression Profiling ; Humans ; Ouabain ; pharmacology ; Umbilical Veins ; cytology

High concentrations of oxygen, indispensable for the treatment of severe hypoxemia from neonatal as well as adult respiratory distress syndrome, increase the risk of oxygen toxicity. Biochemical mechanisms are lipid peroxidation, protein sulfhydryl oxidation, enzyme inactivation, and DNA damage. Recent reports suggest that cytokines might be involved in free radical injury as well as in adaptive response to hyperoxic injury. However, actual signal transduction pathways involving cytokines have not yet been clarified. In this study we exposed cultured human umbilical vein endothelial cells (HUVECs) to either ambient air or 100% oxygen, and compared for the rate of DNA synthesis ([3H]thymidine uptake) at different time points up to 72 h. After exposing the cells to each treatment condition, we extracted RNA, constructed complementary DNA using reverse transcriptase, amplified the specific DNA segments of cytokines by polymerase chain reaction (PCR), and used the PCR products for gel electrophoresis to examine the bands which signified mRNA levels of corresponding cytokines. There was a significant decrease in the rate of DNA synthesis as early as 24 h. The mRNA expression of IL-1 beta and TNFa seemed less influenced by hyperoxia, while IL-8 and TGF beta showed marked increase in mRNA levels at 6 h of 100% oxygen exposure.
Cells, Cultured ; Cytokines/genetics* ; DNA/biosynthesis ; Endothelium, Vascular/metabolism* ; Human ; Hyperoxia/metabolism* ; RNA, Messenger/analysis* ; Umbilical Veins

Connexin43 has been shown to play a pivotal role in wound healing process. Wound repair is enhanced by acute downregulation of connexin43, by increasing proliferation and migration of keratinocyte and fibroblast. Angiogenesis is also a central feature of wound repair, but little is known about the effects of connexin43 modulation on functions of endothelial cells. We used connexin43 specific small interference RNA (siRNA) to reduce the expression of connexin43 in human umbilical vein endothelial cell (HUVEC), and investigated the effects of connexin43 downregulation on intercellular communication, viability, proliferation, migration and angiogenic activity of HUVEC. Treatment of siRNA markedly reduced the expression of connexin43 by -80% in HUVEC (P < 0.05), and decreased the intercellular communication by -65% (P < 0.05). The viability, proliferation, migration and angiogenic activity of HUVEC decreased significantly (P < 0.05), compared with that of the normal cells. The results suggest that temporally downregulation of connexin43 expression at early stage of wound to inhibit the abnormal angiogenesis characterized with leaky and inflamed blood vessels, maybe a prerequisite for coordinated normal healing process.
Cell Movement ; Cell Proliferation ; Cell Survival ; Connexin 43 ; metabolism ; Down-Regulation ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Neovascularization, Physiologic ; Umbilical Veins ; cytology ; Wound Healing

OBJECTIVETo investigate the penetrating ability of fusion protein PEP-1-EGFP with human umbilical vein endothelial cells.

METHODSTwo prokaryotic expression plasmids pET15b-EGFP and pET15b-PEP-1-EGFP were constructed and transformed into E. coli BL21 (DE3) to express EGFP and fusion protein PEP-1-EGFP, respectively. The expressed EGFP and PEP-1-EGFP were purified with Ni(2+) -resin affinity chromatography, and their capabilities of transduction into human umbilical vein endothelial cells were evaluated. The time- and dose-dependent transduction of the fusion protein PEP-1-EGFP and its stability in the human umbilical vein endothelial cells were observed. The toxicity of the fusion protein PEP-1-EGFP was detected by MTT method.

RESULTSEGFP failed to be transduced into human umbilical vein endothelial cells, whereas PEP-1-EGFP fusion protein was transduced into cells shortly in 5 minutes. Its transduction was time- and dose-dependent and the fluorescence in the cells were detected even 27 hours later. No cytotoxicity of the fusion protein PEP-1-EGFP to human umbilical vein endothelial cells was detected even when the dose reached up to 200 micromol/L.

CONCLUSIONPEP-1-EGFP fusion protein can efficiently transduce the target protein into human umbilical vein endothelial cells, which provides a basis for future researches on the transduction of antioxidant enzymes mediated by the cell-penetrating peptide, PEP-1, in ischemia-reperfusion injury therapy.

Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Green Fluorescent Proteins ; metabolism ; Humans ; Peptides ; metabolism ; Protein Transport ; Recombinant Fusion Proteins ; metabolism ; toxicity ; Umbilical Veins ; cytology

Extensive monocyte recruitment is an early phenomenon associated with the development of atherosclerotic lesion. Although the molecular mechanisms are not completely understood, monocyte recruitment into these early lesions may involve changes in endothelial adhesion for monocyte, in which adhesion molecules expressed by endothelial cell play an active role. In vivo, the function of endothelial cells is not only affected by the chemical factors, but also by the mechanical factors. The purpose of this article was to investigate the induction of adhesion molecules expression by synergistic effects of Lysophosphatidylcholine (Lyso-PC) and shear stress in cultured human umbilical vein endothelial cells (HUVEC). The surface expression of ICAM-1, VCAM-1 and E-selectin on HUVEC induced by Lyso-PC(30 micrograms/ml) and shear stress(2.23, 4.20 dyne/cm2) were analyzed using flow cytometry. The results showed that: Compared with what were simultaneously exposed to shear stress and Lyso-PC, activating the cells with Lyso-PC prior to shear stress, or pre-conditioning the cells exposed shear stress prior to Lyso-PC incubation, a significantly higher expression of ICAM-1 and VCAM-1(P < 0.05) was resulted. HUVEC were exposed to shear stress and Lyso-PC at the same time or treated with each agonist alone, E-selectin expression was not significantly different from the control group. However, a sequential action of the two stimuli significantly increased E-selectin expression(P < 0.05). We concluded that: a sequential action of the shear stress and Lyso-PC induced an even greater expression of ICAM-1 and VCAM-1, thus it could be understood that the flows-hear stress in combination with endothelial activated by chemical factors may increase the ability of endothelial cells to recruit leukocytes even under the mechanical environment unfavorable for cell adhesion.
Cell Adhesion Molecules ; biosynthesis ; Cells, Cultured ; Endothelium, Vascular ; cytology ; drug effects ; metabolism ; Humans ; Lysophosphatidylcholines ; pharmacology ; Stress, Mechanical ; Umbilical Veins ; cytology

Fluid shear stress plays an important role in many physiological and pathological processes of the cardiovascular system. Being constantly exposed to mechanical shear stress, vascular endothelial cells can sense the changes of blood flow forces and regulate vascular structure and function. Previous studies demonstrated that IL-8 mRNA expression in endothelial cells was modulated by fluid shear stress. To identify the effect of fluid shear stress on IL-8 protein production of human umbilical vein endothelial cells (HUVECs), we employed quantitative sandwich enzyme-linked immunosorbent assay (ELISA) to measure the IL-8 protein. It was found that the HUVECs not treated with fluid shear stress secreted very little IL-8 in culture media. However, after 1 hour of exposure to shear stress, the secretion of IL-8 increased; at 5 hours of exposure, the seceretion reached the summit; at 8 hours of exposure, the secretion of IL-8 decreased and then remained at a constant level till the end (12 hours) of the experiment. The increase of IL-8 secretion induced by shear stress was time-dependent. The biphasic response of IL-8 protein production was found in experiments in which the shear stress applied was 2.09 dyne/cm2, 4.61 dyne/cm2, and 6.19 dyne/cm2. The IL-8 protein production in response to shear stress was very similar to the IL-8 gene expression in response to shear stress, and had the obvious delay. The induction of IL-8 protein production by fluid shear stress is probably due to the gene expression. This in vitro study demonstrates that the production of IL-8 can be regulated by fluid shear stress. Fluid shear stress induces a biphasic response of human HUVECs' production of IL-8 protein. These observations suggest that the process of the fluid shear stress induced HUVECs' production of IL-8 may play an important role in the genesis and development of both inflammation and atherosclerosis.
Cells, Cultured ; Endothelial Cells ; metabolism ; Endothelium, Vascular ; cytology ; Humans ; Interleukin-8 ; biosynthesis ; Stress, Mechanical ; Umbilical Veins ; cytology

OBJECTIVETo investigate the influence of hypoxia on the proliferation and activity of human umbilical vein vascular endothelial cells (EA. hy926).

METHODSEA. hy926 cells were cultured in vitro and divided into normal control and hypoxia groups. The cells in hypoxia group were placed into hypoxic jar and treated with mixed gases(94% N2 +5% CO2 + 1% O2) for 1,3,6 and 12 hours. Then the total proteins were extracted for the determination of the expression of vascular endothelial growth factor (VEGF) and proliferation cell nuclear antigen (PCNA). The cell cycle and growth curve were determined with flow cytometry and MTT method, respectively.

RESULTSThe expression of PCNA protein began to increase at 3 post-hypoxia hour (PHH), peaked at 6 PHH, but without obvious difference compared with that at 12 PHH. The expression of VEGF began to increase at 1 PHH, peaked at 6 PHH, and decreased at 12 PHH, though it was still markedly higher than that of normoxia at 12 PHH. MTT results showed that the cell activity began to increase at 1 PHH, and it was still to increased at 3 PHH, then decreased at 6 PHH, and it was lower than that in control group at 12 PHH. The number of cells in G0/G1 phase was decreased, but the cells in S and G2/M phase was increased at 1, 3, 6 PHH when compared with those in normal controls. The proliferation index (PI) of cells in hypoxia group at 1PHH (43 +/- 9)%, 3PHH (39 +/- 11)%, 6 PHH (40 +/- 11))% were higher than that before hypoxia (32 +/- 9)% and 3 (39 +/- 11) % and 6 hours (40 +/- 11)% after hypoxia (P < 0.05). The PI was obviously lower at 12 PHH (27 +/- 4))% compared with that of cells under normoxic condition (P < 0.05).

CONCLUSIONShort-term hypoxia is beneficial to promote the proliferation of the cells, but this effect will be inhibited with the prolongation of hypoxia.

Cell Hypoxia ; Cell Proliferation ; Cells, Cultured ; Endothelial Cells ; metabolism ; Humans ; Hypoxia ; metabolism ; pathology ; Proliferating Cell Nuclear Antigen ; metabolism ; Umbilical Veins ; cytology ; Vascular Endothelial Growth Factor A ; metabolism