• Molecules and Cells
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• 제37권6호
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• pp.487-496
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• 2014

Angiotensinogen (AGT), the precursor of angiotensin I, is known to be involved in tumor angiogenesis and associated with the pathogenesis of coronary atherosclerosis. This study was undertaken to determine the role played by AGT in endothelial progenitor cells (EPCs) in tumor progression and metastasis. It was found that the number of EPC colonies formed by AGT heterozygous knockout ($AGT^{+/-}$) cells was less than that formed by wild-type (WT) cells, and that the migration and tube formation abilities of $AGT^{+/-}$ EPCs were significantly lower than those of WT EPCs. In addition, the gene expressions of vascular endothelial growth factor (VEGF), Flk1, angiopoietin (Ang)-1, Ang-2, Tie-2, stromal derived factor (SDF)-1, C-X-C chemokine receptor type 4 (CXCR4), and of endothelial nitric oxide synthase (eNOS) were suppressed in $AGT^{+/-}$ EPCs. Furthermore, the expressions of hypoxia-inducible factor (HIF)-$1{\alpha}$and $-2{\alpha}$ were downregulated in $AGT^{+/-}$ early EPCs under hypoxic conditions, suggesting a blunting of response to hypoxia. Moreover, the activation of Akt/eNOS signaling pathways induced by VEGF, epithelial growth factor (EGF), or SDF-$1{\alpha}$ were suppressed in $AGT^{+/-}$ EPCs. In $AGT^{+/-}$ mice, the incorporation of EPCs into the tumor vasculature was significantly reduced, and lung tumor growth and melanoma metastasis were attenuated. In conclusion, AGT is required for hypoxia-induced vasculogenesis.

• Molecules and Cells
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• 제37권4호
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• pp.330-336
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• 2014

Thymosin beta4 (TB4) has multiple functions in cellular response in processes as diverse as embryonic organ development and the pathogeneses of disease, especially those associated with cardiac coronary vessels. However, the specific roles played by TB4 during heart valve development in vertebrates are largely unknown. Here, we identified a novel function of TB4 in endothelial-mesenchymal transformation (EMT) in cardiac valve endocardial cushions in zebrafish. The expressions of thymosin family members in developing zebrafish embryos were determined by whole mount in situ hybridization. Of the thymosin family members only zTB4 was expressed in the developing heart region. Cardiac valve development at 48 h post fertilization was defected in zebrafish TB4 (zTB4) morpholino-injected embryos (morphants). In zTB4 morphants, abnormal linear heart tube development was observed. The expressions of bone morphogenetic protein (BMP) 4, notch1b, and hyaluronic acid synthase (HAS) 2 genes were also markedly reduced in atrio-ventricular canal (AVC). Endocardial cells in the AVC region were stained with anti-Zn5 antibody reactive against Dm-grasp (an EMT marker) to observe EMT in developing cardiac valves in zTB4 morphants. EMT marker expression in valve endothelial cells was confirmed after transfection with TB4 siRNA in the presence of transforming growth factor ${\beta}$ ($TGF{\beta}$) by RT-PCR and immunofluorescent assay. Zn5-positive endocardial AVC cells were not observed in zTB4 morphants, and knockdown of TB4 suppressed TGF-${\beta}$-induced EMT in ovine valve endothelial cells. Taken together, our results demonstrate that TB4 plays a pivotal role in cardiac valve formation by increasing EMT.

• Journal of Ginseng Research
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• 제32권3호
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• pp.244-249
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• 2008

Vascular inflammation is an important step in the development of cardiovascular disorder. Since it has not been known whether Korean red ginseng has a role to play on the vascular inflammation, we investigated the effects of Korean red ginseng extract (KRGE) on monocyte adhesion and its underlying signaling mechanism. Monocyte adhesion assay and Western blot were conducted on the human umbilical vein endothelial cells to study monocyte adhesion and the expression of adhesion molecules. Intracellular calcium was measured with Fura-2 fluorescent staining, and superoxide production was measured with lucigenin chemiluminescence in the endothelial cells. KRGE inhibits tumor necrosis factor (TNF)-alpha-induced monocyte adhesion on the endothelial cells at the range of $0.03{\sim}1$ mg/ml. TNF-alpha-induced vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1 expression were inhibited by the pretreatment of KRGE in the endothelial cells. KRGE also inhibits TNF-alpha-induced intracellular calcium and the superoxide production in the endothelial cells. This study first demonstrated that KRGE inhibits TNF-alpha-induced monocyte adhesion by inhibiting the adhesion molecule expression, intracellular calcium and superoxide production in the endothelial cells. Therefore, the anti-inflammatory function of KRGE may be contributed to protecting the endothelial dysfunction in the vascular inflammatory disorders.

• 생명과학회지
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• 제19권12호
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• pp.1777-1786
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• 2009

사이모신 베타 4와 VEGF의 발현을 여러 인간 조직에서 tissue microarray를 사용하여 조사하였다. 사이모신 베타 4는 간, 이자, 침샘의 관상피, 심장에서 강한 발현을 보였으며 피부, 폐, 이자, 림프절, 갑상선, 요관, 폐와 부신의 혈관 내피세포 등에서 중간 수준의 발현 양상을 보였다. VEGF의 발현 양상은 대체적으로 사이모신 베타 4와 동일하였으며 이자, 요관, 유선, 간, 식도, 신장, 폐, 부신 등의 혈관 내피세포에서 강하게 발현되었다. 이러한 결과를 통해 사이모신 베타 4는 간, 이자, 침샘의 관상피, 심장에서 중요한 역할을 담당하며 VEGF와 같은 발현 양상을 보여 혈관 신생작용에 관여함을 확인하였다.

• 생명과학회지
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• 제30권7호
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• pp.651-659
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• 2020

허혈성 심혈관질환은 전 세계적으로 치사율이 높은 질병 중 하나이다. 이를 치료하기 위해 수술적 방법이 시행되고 있으나, 손상된 심근조직 회복의 어려움과 수술 후 부작용의 한계가 남아있다. 이러한 한계점을 극복하기 위해, 최근 줄기세포를 기반으로 한 심혈관질환의 세포치료제가 각광받고 있는데 그 중에서도 특히 혈관내피전구세포(EPC)는 높은 증식능과 분화능을 기반으로 손상된 혈관을 재생하고, 주변 조직의 재생을 돕는다는 장점이 있다. 또, EPC는 임상적으로 안전하며, 환자의 심근 기능을 회복시켜주기에 잠재적인 심혈관질환 치료제로서의 가능성이 대두되었다. 하지만, 환자 유래 EPC를 이용한 치료법은, 고령, 흡연 여부, 기저질환 등의 이유로 환자의 EPC 기능이 저하되어 있어, 그 치료 효능을 기대하기 어렵다. 따라서, 최근에는 세포 프라이밍 기법, 오가노이드 배양법과 같이 EPC의 생리학적 활성도를 올리는 체외 배양법의 개발과 3D 바이오프린팅 기법을 이용한 EPC의 이식 효율을 높여 치료 효능을 개선시킬 수 있는 새로운 접근법이 연구되고 있다. 본 연구에서는 EPC의 특징과 세포치료제로서의 임상적용 가능성에 대해 살펴보고자 한다.

• IMMUNE NETWORK
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• 제15권4호
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• pp.206-211
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• 2015

Pulmonary edema is a major cause of mortality due to acute lung injury (ALI). The involvement of protein kinase C-${\delta}$ (PKC-${\delta}$) in ALI has been a controversial topic. Here we investigated PKC-${\delta}$ function in ALI using PKC-${\delta}$ knockout (KO) mice and PKC inhibitors. Our results indicated that although the ability to produce proinflammatory mediators in response to LPS injury in PKC-${\delta}$ KO mice was similar to that of control mice, they showed enhanced recruitment of neutrophils to the lung and more severe pulmonary edema. PKC-${\delta}$ inhibition promoted barrier dysfunction in an endothelial cell layer in vitro, and administration of a PKC-${\delta}$-specific inhibitor significantly increased steady state vascular permeability. A neutrophil transmigration assay indicated that the PKC-${\delta}$ inhibition increased neutrophil transmigration through an endothelial monolayer. This suggests that PKC-${\delta}$ inhibition induces structural changes in endothelial cells, allowing extravasation of proteins and neutrophils.

• 대한한의학회지
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• 제25권2호
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• pp.173-183
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• 2004

Objectives : Oxidative stress can induce negative responses such as growth inhibition or cell death by necrosis or apoptosis due to the intensity of the oxidative stress, as well as positive responses such as cellular proliferation or activation. We examined the effect of Jihwangeumja on this process. Methods and Results : We analyzed the influence of oxidative stress and agents that modify its effect in human umbilical vein endothelial cell (HUVEC). Oxidative stress was induced by $B_2O_2$. With induced oxidative stress the results obtained indicate that it has a harmful effect over cell function and viability, and that this effect is dose and time dependent. When oxidative stress increased, Jihwangeumja reduced cell damage and had protective functions. $B_2O_2$, induced the apoptosis of HUVEC through the activation of intrinsic caspases pathway as well as mitochondrial dysfunction. A significant increase in cell survival was observed in culture cells with oxidative stress when they were treated with Jihwangeumja. Conclusions : These results suggest that Jihwangeumja may be potentially useful to treat HUVEC against oxidative damages mediated by modulation of caspase protease and mitochondrial dysfunction.

• The Korean Journal of Physiology and Pharmacology
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• 제18권3호
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• pp.201-209
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• 2014

The present study was designed to investigate the efficacy of selective $ET_A$ receptor antagonist, ambrisentan on hyperhomocysteinemia-induced experimental vascular dementia. L-methionine was administered for 8 weeks to induce hyperhomocysteinemia and associated vascular dementia in male rats. Ambrisentan was administered to L-methionine-treated effect rats for 4 weeks (starting from $5^{th}$ to $8^{th}$ week of L-methionine treatment). On $52^{nd}$ day onward, the animals were exposed to the Morris water maze (MWM) for testing their learning and memory abilities. Vascular endothelial function, serum nitrite/nitrate levels, brain thiobarbituric acid reactive species (TBARS), brain reduced glutathione (GSH) levels, and brain acetylcholinesterase (AChE) activity were also measured. L-methionine-treated animals showed significant learning and memory impairment, endothelial dysfunction, decrease in/serum nitrite/nitrate and brain GSH levels along with an increase in brain TBARS levels and AChE activity. Ambrisentan significantly improved hyperhomocysteinemia-induced impairment of learning, memory, endothelial dysfunction, and changes in various biochemical parameters. These effects were comparable to that of donepezil serving as positive control. It is concluded that ambrisentan, a selective $ET_A$ receptor antagonist may be considered as a potential pharmacological agent for the management of hyperhomocysteinemia-induced vascular dementia.

• BMB Reports
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• 제51권2호
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• pp.73-78
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• 2018

Vascular endothelial growth factor and its receptor (VEGF-VEGFR) system play a critical role in the regulation of angiogenesis and lymphangiogenesis in vertebrates. Each of the VEGF has specific receptors, which it activates by binding to the extracellular domain of the receptors, and, thus, regulates the angiogenic balance in the early embryonic and adult stages. However, de-regulation of the VEGF-VEGFR implicates directly in various diseases, particularly cancer. Moreover, tumor growth needs a dedicated blood supply to provide oxygen and other essential nutrients. Tumor metastasis requires blood vessels to carry tumors to distant sites, where they can implant and begin the growth of secondary tumors. Thus, investigation of signaling systems related to the human disease, such as VEGF-VEGFR, will facilitate the development of treatments for such illnesses.

• The Korean Journal of Physiology and Pharmacology
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• 제20권4호
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• pp.325-332
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• 2016

Resveratrol, a phytoalexin, is reported to activate AMP-activated protein kinase (AMPK) in vascular cells. The blood-brain barrier (BBB), formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. The aim of this study was to elucidate the effects of resveratrol and the role of AMPK in BBB dysfunction induced by lipopolysaccharide (LPS). Exposure of human brain microvascular endothelial cells (HBMECs) to LPS ($1{\mu}g/ml$) for 4 to 24 hours week dramatically increased the permeability of the BBB in parallel with lowered expression levels of occluding and claudin-5, which are essential to maintain tight junctions in HBMECs. In addition, LPS significantly increased the reactive oxygen species (ROS) productions. All effects induced by LPS in HBVMCs were reversed by adenoviral overexpression of superoxide dismutase, inhibition of NAD(P) H oxidase by apocynin or gain-function of AMPK by adenoviral overexpression of constitutively active mutant (AMPK-CA) or by resveratrol. Finally, upregulation of AMPK by either AMPK-CA or resveratrol abolished the levels of LPS-enhanced NAD(P)H oxidase subunits protein expressions. We conclude that AMPK activation by resveratrol improves the integrity of the BBB disrupted by LPS through suppressing the induction of NAD(P)H oxidase-derived ROS in HBMECs.