• Biomolecules & Therapeutics
• /
• 제3권3호
• /
• pp.188-191
• /
• 1995

The Present study was undertaken to indicate the major source of NO by liver cells in vitro. Even at early stages of induction or low LPS concentrations, NO was produced at high rates by LPS(Lipopolysaccharide) on the isolated rat kupffer cells. PMA(phorbol 12-myristate 13-acetate) induced NO formation at low rates in the same cells. IFN-${\gamma}$ (Interferon-${\gamma}$) alone had not induced NO formation but it stimulated the effects of LPS. Calcium ionophore A23187 caused no stimulatory effect. It suggests that LPS has especially strong NO inducer on the kupffer cells and its mechanism is related to those on macrophage in other organs. In other nonparenchymal liver cells, sinusoidal endothelial cells were not stimulated to produce NO either by inducers of aortic endothelium(A23187, ATP and ADP) or by effectors of macrophages(LPS, IFN-${\gamma}$. This results suggest that rat liver kupffer cells appear to be the major source of NO by liver cells in vitro. But in vivo, liver endothelial cells may still be capable of producing NO. Furthermore, kupffer cells may produce factors that facilitate NO production by the endothelial cells.

• Molecules and Cells
• /
• 제22권1호
• /
• pp.70-77
• /
• 2006

Platelets are anucleate cytoplasmic fragments derived from bone marrow megakaryocytes, and endothelial cells constitute the barrier between bloodstream and adjacent tissues. Although platelets are thought to regulate the biological functions of endothelial cells, the molecular mechanisms involved are poorly understood. With human umbilical vein endothelial cells and freshly isolated platelets, we established an in vitro model of platelet-induced endothelial cell proliferation. Platelets stimulated endothelial cell proliferation in a dose-dependent manner and transwell experiments with semi-permeable membranes suggested that direct cell-to-cell contacts were required. We developed mAbs against platelets and selected a mAb that blocks their proliferative effect. We purified the antigen by immunoprecipitation and identified it by Q-TOF MS analysis as the tetraspanin CD9. Since both platelets and endothelial cells expressed CD9 strongly on their surfaces we carried out a pre-treatment experiment that showed that CD9 molecules on the endothelial cells participate in the mitogenic effect of the platelets. The inhibitory effect of our mAb was comparable to that of a well-known functional anti-CD9 mAb. These results suggest that the tetraspanin CD9 plays an important role in endothelial regeneration.

• BMB Reports
• /
• 제38권4호
• /
• pp.447-456
• /
• 2005

TNF-$\alpha$ plays a pivotal role in inflammation processes which are mainly regulated by endothelial cells. While TNF-$\alpha$ induces apoptosis of several cell types like tumor cells, endothelial cells are resistant to TNFa mediated cell death. The cytotoxic effects of TNF-$\alpha$ on most cells are only evident if RNA or protein synthesis is inhibited, suggesting that de novo RNA or protein synthesis protect cells from TNF-$\alpha$ cytotoxicity, presumably by NF-${\kappa}B$ mediated induction of protective genes. However, the cytoprotective genes involved in NF-${\kappa}B$ dependent endothelial cell survival have not been sufficiently identified. In the present study, the suppression subtractive hybridization (SSH) method was employed to identify rarely transcribed TNF-$\alpha$ inducible genes in human arterial endothelial cells related to cell survival and cell cycle. The TNF-$\alpha$-induced expression of the RNA binding protein $p54^{nrb}$ and the 14-3-3 protein HS1 as shown here for the first time may contribute to the TNF-$\alpha$ mediated cell protection of endothelial cells. These genes have been shown to play pivotal roles in cell survival and cell cycle control in different experimental settings. The concerted expression of these genes together with other genes related to cell protection and cell cycle like DnaJ, $p21^{cip1}$ and the ubiquitin activating enzyme E1 demonstrates the identification of new genes in the context of TNF-$\alpha$ induced gene expression patterns mediating the prosurvival effect of TNF-$\alpha$ in endothelial cells.

• 대한의생명과학회지
• /
• 제12권3호
• /
• pp.255-259
• /
• 2006

Reactive oxygen species (ROS) is one of the main pathological factors in endothelial disorder. For example, an atherosclerosis is induced by the dysfunction of vascular endothelial cells. The dysfunction of vascular endothelial cells cascades to secrete intercellular adhesion molecule (ICAM)-l substance by ROS. Therefore, The ROS is regraded as an important factor of the injury of vascular endothelial cells and inducement of atherosclerosis. Oxygen radical scavengers playa key role to prevention of many diseases mediated by oxidative stress of ROS. In this study, the toxic effect of ROS on vascular endothelial cells and the effect of antioxidant, vitamin E on bovine pulmonary vascular endothelial cell line (BPVEC) treated with hydrogen peroxide were examined by the colorimetric assay. ROS decreased remarkably cell viability according to the dose- and time-dependent manners. In protective effect of vitamin E on BPVEC treated with hydrogen peroxide, vitamin E increased remarkably cell viability compared with control after BPVEC were treated with $15{\mu}M$ hydrogen peroxide for 6 hours. From these results, it is suggested that ROS has cytotoxicity on cultured BPVEC and oxygen radical scavenger such as vitamin E is very effective in prevention of oxidative stress-induced cytotoxicity.

• 대한방사선치료학회지
• /
• 제12권1호
• /
• pp.166-173
• /
• 2000

Angiopoietin-1(Ang-1) is a vasculogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. We examined the effect of angiopoietin-1(Ang-1) on radiation-induced apoptosis in human umbilical vein endothelial cells(HUVECS) and receptor/second messenger signal transduction pathway for Ang-1's effect on HUVECs. The percent of apoptotic cells under control condition(0Gy) was $8.2\%$. Irradiation induced apoptosis was increased in a dose(1, 5, 10, and 15Gy)- and time 12, 24, 48 and 72hr)-dependent manner. The percent of apoptotic cells was approximately $34.9\%$ after 15 Gy of irradiation. Under these conditions, pretreatment with Ang-1's (50, 100, 200, and 400 ng/ml) inhibited irradiation-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Two hundred ng/ml of Ang-1 inhibited approximately $55-60\%$ of the apoptotic events that occurred in the 10 Gy-irradiated cells. Pre-treatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the Ang-1's antiapoptotic effects. Phosphatidylinositol 3'-kinase (P13-kinase) specific inhibitor, wortmanin and LY294002, blocked the Ang-1-induced antiapoptotic effect. Ang-1 promotes the survival of endothelial cells in irradiation-induced apoptosis through Tie2 receptor binding and P13-kinase activation. Pretreatment of Ang-1 could be beneficial in maintaining normal endothelial cell integrity during irradiation therapy.

• Journal of Nutrition and Health
• /
• 제32권3호
• /
• pp.318-326
• /
• 1999

Apoptotic cell death, characterized by DNA fragmentation and morphological changes, has previously been shown to occur in vascular endothelial cells cultured with hydrogen peroxide. The present study examined the induction of apoptosis by hydrogen peroxide and whether pyruvate, a key glycolytic intermediate and $\alpha$-keto-monocarboxylate, can inhibit the apoptotic effects in bovine pulmonary artery endothelial cells(BPAECs). Culture with 500uM hydrogen peroxide resulted in 30% cell death and induced morphological changes and DNA fragmentation. Cell injury was inhibited by the treatment with pyruvate. Pyruvate(0.1-5.0mM), and cell viability increased in a dose-dependent manner. In the presence of pyruvate(10~20mM), the viability was improved to over 95%. In contrast, treatment with lactate, a reduced form of phyuvate, did not protect against cell death oxidative stress-induced loss of viability and apoptosis was examined with $\alpha$-cyano-3-hydroxycinnarmate(COHC) as a selective mitochondrial monocarboxylate transport blocker. Incubation with COHC(500uM) did not significantly affect cell viability in the presence of hydrogen peroxide. The cytoprotection by pyruvate(3mM)against hydrogen peroxide stress was abolished by COHC. This indicates that the cytoprotection by pyruvate against oxidative stress in endothelial cells is mediated, at least in part, by mitochondrial pyruvate uptake and hence endothelial enerygetics. However, cytosolic mechanisms related, at least in part, by mitochondrial pyruvate uptake and hence endothelial energetics. However, cytosolic mechanisms related to the glutathione system may also contribute. The results suggest that pyruvate has therapeutic potential in the treatment of oxidative stress-induced cytotoxicity associated with increased apoptosis.

• 동의생리병리학회지
• /
• 제17권1호
• /
• pp.220-224
• /
• 2003

To test the protective effect of Sophorae Radix (SR) on the damage of cardiac endothelial cells by xanthine oxidase (XO)/hypoxanthine (HX)-induced oxygen tree radical, Neutral Red (NR), lactate dyhydrogenase (LDH), and c-fos immunopositive cells assay were used in the presence of SR extract. The results of these experiments were obtained as follows ; Cardiac endothelial cells treated with XO/HX showed the cytotoxicity such as a decrease in viability, and increases in LDH activity and c-fos immunopositive cells. Cardiac endothelial cells pretreated with SR extract protected the increase of LDH activity. Alos, cardiac endothelial cells pretreated with SR extract inhibited the increase of c-fos immunopositive cells. These results show that XO/HX induces toxic effects in cultured cardiac endothelial cells derived from neonatal rat, and suggest that SR extract is very effective in the prevention of XO/HX-induced toxicity.

• 대한수의학회지
• /
• 제43권4호
• /
• pp.551-554
• /
• 2003

Nitric oxide synthase (NOS) has been reported in uterus. We examined the expression of the NOS isoforms, constitutive endothelial (eNOS) and inducible NOS (iNOS), in bovine uterus by immunohistochemistry. eNOS immunoreactivity was localized predominantly to the endothelial cells that line uterine microvessels and to endometrial glandular epithelial cells, but was barely detectable in endometrial stromal cells. iNOS immunostaining was detected in glandular epithelial and stromal cells in the endometrium and in the endothelial cells of myometrial blood vessels. These findings suggest that both eNOS and iNOS may play important roles in the physiology of the uterus, possibly by generating NO.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제11권5호
• /
• pp.402-407
• /
• 2006

Vascular endothelial cells release proteinases that degrade the extracellular matrix (ECM), thus enabling cell migration during angiogenesis and vasculogenesis. Sildenafil citrate stimulates the nitric oxide-cyclic guanosine monophosphate pathway through inhibition of phosphodiesterase type V (PDE5). In this report, we examined the mechanisms underlying sildenafil citrate-induced cell migration using cultured mouse aortic endothelial cells (MAECs). Sildenafil citrate induced migration and proteinase secretion by murine endothelial cells. Sildenafil citrate induced the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9, which is inhibited by $NF-{\kappa}B$ inhibitors. Sildenafil citrate also induced the secretion of plasmin, which is inhibited by PI 3'-kinase inhibitors. It is suggested that sildenafil citrate-induced migrating activity in endothelial cells may be accomplished by increased secretion of proteinases.

• Journal of Applied Biological Chemistry
• /
• 제48권4호
• /
• pp.178-182
• /
• 2005

Nitric oxide (NO) produced from endothelial cells plays a critical role in vascular physiology. The regulation of endothelial NO synthase (eNOS) involves various mechanisms including multiple Ser/Thr phosphorylations. Recently, eNOS-Ser617 was newly recognized to be phosphorylated in response to humoral factors including vascular endothelial growth factor. However, it remains unknown whether and how eNOS-Ser617 phosphorylation is stimulated by shear stress, the primary stimulus of endothelial NO production. This issue was explored in the present study using cultured bovine aortic endothelial cells (BAECs). Over-expression of a constitutively active protein kinase B(Akt) mutant in BAECs increased Ser617 phosphorylation while constitutively active protein kinase A mutant had no effect. When BAECs were subjected to an arterial level of laminar shear stress, eNOS-Ser617 phosphorylation was clearly increased in a time-dependent manner. Shear stress also stimulated Akt phosphorylation at Thr308, one of the key regulatory sites. The time courses of eNOS-Ser617 and Akt-Thr308 phosphorylations appeared to be very similar. These results suggested that eNOS-Ser617 phosphorylation, mediated by Akt, is a physiological response to the mechanical shear stress, involved in the regulation of NO production in endothelial cells.