• IMMUNE NETWORK
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• v.13 no.2
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• pp.55-62
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• 2013

Swiprosin-1 exhibits the highest expression in $CD8^+$ T cells and immature B cells and has been proposed to play a role in lymphocyte biology through actin remodeling. However, regulation of swiprosin-1 gene expression is poorly understood. Here we report that swiprosin-1 is up-regulated in T cells by PKC pathway. Targeted inhibition of the specific protein kinase C (PKC) isotypes by siRNA revealed that $PKC-{\theta}$ is involved in the expression of swiprosin-1 in the human T cells. In contrast, down-regulation of swiprosin-1 by A23187 or ionomycin suggests that calcium-signaling plays a negative role. Interestingly, swiprosin-1 expression is only reduced by treatment with $NF-{\kappa}B$ inhibitors but not by NF-AT inhibitor, suggesting that the $NF-{\kappa}B$ pathway is critical for regulation of swiprosin-1 expression. Collectively, these results suggest that swiprosin-1 is a $PKC-{\theta}$-inducible gene and that it may modulate the late phase of T cell activation after antigen challenge.

• Journal of Life Science
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• v.27 no.1
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• pp.1-7
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• 2017

Abnormal actin remodeling is a typical characteristic of tumor cells. Thymosin ${\beta}_{10}$ (TB10) and profilin-1 (PFN-1) are actin-binding proteins and essential regulators of actin polymerization. We previously showed that TB10 induced death in ovarian cancer cells by sequestering F-actin, but the underlying mechanisms of this induction have not been explored. In this study, we identified TB10 as a novel regulator of PFN-1 and demonstrated its novel function as a tumor suppressor in ovarian cancer cell lines. The present study investigated protein expression profiles through polyacrylamide gel electrophoresis (PAGE) and liquid chromatography-mass spectroscopy (LC-MS/MS) in SKOV3 cells, an ovarian cancer cell line, that were transiently transfected with TB10. PFN-1 was highly overexpressed in response to TB10, and overexpression of PFN-1 resulted in inhibition of cell proliferation and migration and promotion of cellular apoptosis in ovarian cancer cells. Furthermore, transiently transfected PFN-1 appeared to deactivate the Erk signaling pathway, followed by decreased expression of Elk-1 and Egr-1 in human ovarian cancer cells. Interestingly, PFN-1 did not affect the activation of Akt. The results demonstrated that PFN-1 induced apoptotic cell death and inhibited proliferation and migration in ovarian cancer cells, suggesting that PFN-1 may be valuable in anti-cancer therapy.

• Journal of Life Science
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• v.25 no.5
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• pp.585-593
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• 2015

Stress fiber (SF) alteration is mediated by cellular receptors, which, upon interaction with the extracellular counterpart, signal to the actin cytoskeleton for remodeling. This association is mediated by a variety of scaffold and signaling factors, which control the mechanical and signaling activities of the interaction site. The heterotrimeric transmembrane lymphotoxin α1β2 (LTα1β2), a member of the tumor necrosis factor (TNF) family of cytokines, including soluble homotrimeric lymphotoxin (LT α), plays an important role in lymphoid tissue architecture. Ligation between LTα1β2 and the lymphotoxin β receptor (LTβR) activates signal-cascade in fibroblastic reticular cells (FRCs). We found LTβR stimulation using an agonistic anti-LTβR antibody alone or combined with LTα or TNFα induced changes in the actin and plasticity of cells. To clarify the involvement of myosin underlying the alteration, we analyzed the effect of myosin light chain kinase (MLCK) with an MLCK inhibitor (ML7), the phosphorylation level of myosin light chains (MLC), and the level of phospho-myosin phosphatase target subunit 1 (MYPT1) after treatment with an agonistic anti-LTβR antibody for cytoskeleton reorganization in FRCs. The inhibition of MLCK activity induced changes in the actin cytoskeleton organization and cell morphology in FRC. In addition, we showed the phosphorylation of MLC and MYPT1 was reduced by LTβR stimulation in cells. A DNA chip revealed the LTβR stimulation of FRC down-regulated transcripts of myosin and actin components. Collectively, these results suggest LTβR stimulation is linked to myosin regarding SF alteration in FRC.

• BMB Reports
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• v.50 no.9
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• pp.437-444
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• 2017

Different types of eukaryotic cells may adopt seemingly distinct modes of directional cell migration. However, several core aspects are regarded common whether the movement is either ameoboidal or mesenchymal. The region of cells facing the attractive signal is often termed leading edge where lamellipodial structures dominates and the other end of the cell called rear end is often mediating cytoskeletal F-actin contraction involving Myosin-II. Dynamic remodeling of cell-to-matrix adhesion involving integrin is also evident in many types of migrating cells. All these three aspects of cell migration are significantly affected by signaling networks of TorC2, TorC1, and PP2A/B56. Here we review the current views of the mechanistic understanding of these regulatory signaling networks and how these networks affect eukaryotic cell migration.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.171-176
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• 2016

Rap1 is a key regulator of cell adhesion and migration. Although increasing evidence indicates that the Rap1 signaling pathway is involved in the process of bone remodeling, the mechanism by which Rap1 regulates osteoblastic differentiation and cell adhesion remains unknown. Here, we investigated the morphological characteristics and osteoblastic differentiation of cells expressing constitutively activated form of Rap1A (Rap1ACA) or Rap1 GTPase activating protein Rap1GAP and found that activated Rap1 induces osteoblastic differentiation and cell adhesion as well as cell spreading. When osteoblastic differentiation was induced, Rap1ACA cells showed considerably higher levels of calcium deposits than the wild-type and Rap1GAP-overexpressing cells did. Rap1ACA cells showed increased spreading and size, as well as strong cell adhesion and significantly decreased growth rates. F-actin staining using phalloidin revealed several thin thread-like filopodia around the protrusions in Rap1ACA cells, which possibly contribute to the increased cell adhesion.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.157-164
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• 2014

PURPOSE. This study focused on in vitro cell differentiation and surface characteristics in a magnesium coated titanium surface implanted on using a plasma ion source. MATERIALS AND METHODS. 40 commercially made pure titanium discs were prepared to produce Ti oxide machined surface (M) and Mg-incorporated Ti oxide machined surface (MM). Surface properties were analyzed using a scanning electron microscopy (SEM). On each surface, alkaline phosphatase (ALP) activity, alizarin red S staining for mineralization of MC3T3-E1 cells, and quantitative analysis of osteoblastic gene expression, were evaluated. Actin ring formation assay and gene expression analysis of TRAP and GAPDH performing RT-PCR were performed to characterize osteoclast differentiation on mouse bone marrow-derived macrophages (BMMs). RESULTS. MM showed similar surface morphology and surface roughness with M, but was slightly smoother after ion implantation at the micron scale. M was more hydrophobic than MM. No significant difference between surfaces on ALP activity at 7 and 14 days were observed. Real-time PCR analyses showed similar levels of mRNA expression of the osteoblast phenotype genes; osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), and collagen 1 (Col 1) in cell grown on MM at 7, 14 and 21 days. Alizarin red S staining at 21 days showed no significant difference. BMMs differentiation increased in M and MM. Actin ring formation assay and gene expression analysis of TRAP showed osteoclast differentiation to be more active on MM. CONCLUSION. Both M and MM have a good effect on osteoblastic cell differentiation, but MM may speed the bone remodeling process by activating on osteoclast differentiation.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.755-760
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• 2015

For proper wound healing, dermal contraction and remodeling are critical; during the natural healing process, differentiated fibroblasts called "myofibroblasts" typically undertake these functions. For severe wounds, however, a critical mass of dermal matrix and fibroblasts are lost, making self-regeneration impossible. To overcome this impairment, synthetic wound patches with embedded functional cells can be used to promote healing. In this study, we developed a polydioxanone (PDO)-based cell-embedded sheet on which dermal fibroblasts were cultured and induced for differentiation into myofibroblasts, whereby the following combinatorial physicochemical stimuli were also applied: aligned topology, electric field (EF), and growth factor. The results show that both the aligned topology and EF synergistically enhanced the expression of alpha smooth-muscle actin (${\alpha}$-SMA), a key myofibroblast marker. Our proof-of-concept (POC) experiments demonstrated the potential applicability of a myofibroblast-embedded PDO sheet as a wound patch.

• Molecules and Cells
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• v.38 no.6
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• pp.528-534
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• 2015

Hypoxia-inducible factor (HIF) is a key regulator of tumor growth and angiogenesis. Recent studies have shown that, BIX01294, a G9a histone methyltransferase (HMT)-specific inhibitor, induces apoptosis and inhibits the proliferation, migration, and invasion of cancer cells. However, not many studies have investigated whether inhibition of G9a HMT can modulate HIF-$1{\alpha}$ stability and angiogenesis. Here, we show that BIX01294 dose-dependently decreases levels of HIF-$1{\alpha}$ in HepG2 human hepatocellular carcinoma cells. The half-life of HIF-$1{\alpha}$, expression of proline hydroxylase 2 (PHD2), hydroxylated HIF-$1{\alpha}$ and von Hippel-Lindau protein (pVHL) under hypoxic conditions were decreased by BIX01294. The mRNA expression and secretion of vascular endothelial growth factor (VEGF) were also significantly reduced by BIX01294 under hypoxic conditions in HepG2 cells. BIX01294 remarkably decreased angiogenic activity induced by VEGF in vitro, ex vivo, and in vivo, as demonstrated by assays using human umbilical vein endothelial cells (HUVECs), mouse aortic rings, and chick chorioallantoic membranes (CAMs), respectively. Furthermore, BIX01294 suppressed VEGF-induced matrix metalloproteinase 2 (MMP2) activity and inhibited VEGF-induced phosphorylation of VEGF receptor 2 (VEGFR-2), focal adhesion kinase (FAK), and paxillin in HUVECs. In addition, BIX01294 inhibited VEGF-induced formation of actin cytoskeletal stress fibers. In conclusion, we demonstrated that BIX01294 inhibits HIF-$1{\alpha}$ stability and VEGF-induced angiogenesis through the VEGFR-2 signaling pathway and actin cytoskeletal remodeling, indicating a promising approach for developing novel therapeutics to stop tumor progression.

• Journal of Chest Surgery
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• v.44 no.6
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• pp.406-412
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• 2011

Background: Development of thoracic aortic aneurysms and aortic dissections (TAAD) is attributed to unbearable wall tension superimposed on defective aortic wall integrity and impaired aortic repair mechanisms. Central to this repair mechanisms are well-balanced and adequately functional cellular components of the aortic wall, including endothelial cells, smooth muscle cells (SMCs), inflammatory cells, and adventitial fibroblasts. Adventitial fibroblasts naturally produce aortic extracellular matrix (ECM), and, when aortic wall is injured, they can be transformed into SMCs, which in turn are involved in aortic remodeling. We postulated the hypothesis that adventitial fibroblasts in patients with TAAD may have defects in ECM production and SMC transformation. Materials and Methods: Adventitial fibroblasts were procured from the adventitial layer of fresh aortic tissues of patients with TAAD (Group I) and of multi-organ donors (Group II), and 4-passage cell culture was performed prior to the experiment. To assess ECM production, cells were treated with TNF-${\alpha}$ (50 pM) and the expression of MMP-2/MMP-3 was analyzed using western blot technique. To assess SMC transformation capacity, cells were treated with TGF-${\beta}1$ and expression of SM ${\alpha}$-actin, SM-MHC, Ki-67 and SM calponin was evaluated using western blot technique. Fibroblasts were then treated with TGF-${\beta}1$ (10 pM) for up to 10 days with TGF-${\beta}1$ supplementation every 2 days, and the proportion of transformed SMC in the cell line was measured using immunofluorescence assay for fibroblast surface antigen every 2 days. Results: MMP-3 expression was significantly lower in group I than in group II. TGF-${\beta}1$-stimulated adventitial fibroblasts in group I expressed less SM ${\alpha}$-actin, SM-MHC, and Ki-67 than in group II. SM-calponin expression was not different between the two groups. Presence of fibroblast was observed on immunofluorescence assay after more than 6 days of TGF-${\beta}1$ treatment in group I, while most fibroblasts were transformed to SMC within 4 days in group II. Conclusion: ECM production and SMC transformation are compromised in adventitial fibroblasts from patients with TAAD. This result suggests that functional restoration of adventitial fibroblasts could well be a novel approach for the prevention and treatment of TAAD.

• Integrative Medicine Research
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• v.3 no.4
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• pp.204-210
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• 2014

The aim of this review was to understand the effects of ${\beta}$-adrenergic stimulation on oxidative stress, structural remodeling, and functional alterations in the heart and cerebral artery. Diverse stimuli activate the sympathetic nervous system, leading to increased levels of catecholamines. Long-term overstimulation of the ${\beta}$-adrenergic receptor (${\beta}AR$) in response to catecholamines causes cardiovascular diseases, including cardiac hypertrophy, stroke, coronary artery disease, and heartfailure. Although catecholamines have identical sites of action in the heart and cerebral artery, the structural and functional modifications differentially activate intracellular signaling cascades. ${\beta}AR$-stimulation can increase oxidative stress in the heart and cerebral artery, but has also been shown to induce different cytoskeletal and functional modifications by modulating various components of the ${\beta}AR$ signal transduction pathways. Stimulation of ${\beta}AR$ leads to cardiac dysfunction due to an overload of intracellular $Ca^{2+}$ in cardiomyocytes. However, this stimulation induces vascular dysfunction through disruption of actin cytoskeleton in vascular smooth muscle cells. Many studies have shown that excessive concentrations of catecholamines during stressful conditions can produce coronary spasms or arrhythmias by inducing $Ca^{2+}$-handling abnormalities and impairing energy production in mitochondria, In this article, we highlight the different fates caused by excessive oxidative stress and disruptions in the cytoskeletal proteome network in the heart and the cerebral artery in responsed to prolonged ${\beta}AR$-stimulation.