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Find video protocols related to scientific articles indexed in Pubmed.
Direct conversion of adult skin fibroblasts to endothelial cells by defined factors.
Circulation
PUBLISHED: 09-03-2014
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Cell-based therapies to augment endothelial cells (ECs) hold great therapeutic promise. Here, we report a novel approach to generate functional ECs directly from adult fibroblasts.
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A case of obstructive jaundice caused by tuberculous lymphadenitis: a literature review.
Clin Mol Hepatol
PUBLISHED: 06-30-2014
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Obstructive jaundice caused by tuberculous lymphadenitis is a rare manifestation of tuberculosis (TB), with 15 cases having been reported in Korea. We experienced a case of obstructive jaundice caused by pericholedochal tuberculous lymphadenitis in a 30-year-old man. The patient's initial serum total bilirubin level was 21.1 mg/dL. Abdominal computed tomography revealed narrowing of the bile duct by a conglomerated soft-tissue mass involving the main portal vein. Abrupt obstruction of the common bile duct was observed on cholangiography. Pathologic analysis of a ultrasonography-guided biopsy sample revealed chronic granulomatous inflammation, and an endoscopic examination revealed esophageal varices and active duodenal ulceration, the pathology of which was chronic noncaseating granulomatous inflammation. Hepaticojejunostomy was performed and pathologic analysis of the conglomerated soft-tissue mass revealed chronic granulomatous inflammation with caseation of the lymph nodes. Tuberculous lymphadenitis should be considered in patients presenting with obstructive jaundice in an endemic area.
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Unique regulation of human Na+/H+ exchanger 3 (NHE3) by Nedd4-2 ligase that differs from non-primate NHE3s.
J. Biol. Chem.
PUBLISHED: 05-15-2014
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Na(+)/H(+) exchanger NHE3 expressed in the intestine and kidney plays a major role in NaCl and HCO3 (-) absorption that is closely linked to fluid absorption and blood pressure regulation. The Nedd4 family of E3 ubiquitin ligases interacts with a number of transporters and channels via PY motifs. A comparison of NHE3 sequences revealed the presence of PY motifs in NHE3s from human and several non-human primates but not in non-primate NHE3s. In this study we evaluated the differences between human and non-primate NHE3s in ubiquitination and interaction with Nedd4-2. We found that Nedd4-2 ubiquitinated human NHE3 (hNHE3) and altered its expression and activity. Surprisingly, rat NHE3 co-immunoprecipitated Nedd4-2, but its expression and activity were not altered by silencing of Nedd4-2. Ubiquitination by Nedd4-2 rendered hNHE3 to undergo internalization at a significantly greater rate than non-primate NHE3s without altering protein stability. Insertion of a PY motif in rabbit NHE3 recapitulated the interaction with Nedd4-2 and enhanced internalization. Thus, we propose a new model where disruption of Nedd4-2 interaction elevates hNHE3 expression and activity.
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Adenylyl cyclase-associated protein 1 is a receptor for human resistin and mediates inflammatory actions of human monocytes.
Cell Metab.
PUBLISHED: 01-03-2014
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Human resistin is a cytokine that induces low-grade inflammation by stimulating monocytes. Resistin-mediated chronic inflammation can lead to obesity, atherosclerosis, and other cardiometabolic diseases. Nevertheless, the receptor for human resistin has not been clarified. Here, we identified adenylyl cyclase-associated protein 1 (CAP1) as a functional receptor for human resistin and clarified its intracellular signaling pathway to modulate inflammatory action of monocytes. We found that human resistin directly binds to CAP1 in monocytes and upregulates cyclic AMP (cAMP) concentration, protein kinase A (PKA) activity, and NF-?B-related transcription of inflammatory cytokines. Overexpression of CAP1 in monocytes enhanced the resistin-induced increased activity of the cAMP-dependent signaling. Moreover, CAP1-overexpressed monocytes aggravated adipose tissue inflammation in transgenic mice that express human resistin from their monocytes. In contrast, suppression of CAP1 expression abrogated the resistin-mediated inflammatory activity both in vitro and in vivo. Therefore, CAP1 is the bona fide receptor for resistin leading to inflammation in humans.
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Comparative study of efficacy of dopaminergic neuron differentiation between embryonic stem cell and protein-based induced pluripotent stem cell.
PLoS ONE
PUBLISHED: 01-01-2014
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In patients with Parkinson's disease (PD), stem cells can serve as therapeutic agents to restore or regenerate injured nervous system. Here, we differentiated two types of stem cells; mouse embryonic stem cells (mESCs) and protein-based iPS cells (P-iPSCs) generated by non-viral methods, into midbrain dopaminergic (mDA) neurons, and then compared the efficiency of DA neuron differentiation from these two cell types. In the undifferentiated stage, P-iPSCs expressed pluripotency markers as ES cells did, indicating that protein-based reprogramming was stable and authentic. While both stem cell types were differentiated to the terminally-matured mDA neurons, P-iPSCs showed higher DA neuron-specific markers' expression than ES cells. To investigate the mechanism of the superior induction capacity of DA neurons observed in P-iPSCs compared to ES cells, we analyzed histone modifications by genome-wide ChIP sequencing analysis and their corresponding microarray results between two cell types. We found that Wnt signaling was up-regulated, while SFRP1, a counter-acting molecule of Wnt, was more suppressed in P-iPSCs than in mESCs. In PD rat model, transplantation of neural precursor cells derived from both cell types showed improved function. The present study demonstrates that P-iPSCs could be a suitable cell source to provide patient-specific therapy for PD without ethical problems or rejection issues.
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Mechanism of edge restenosis after drug-eluting stent implantation.
Circ. J.
PUBLISHED: 10-08-2013
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Background:?Edge restenosis is not an unusual finding after implantation of drug-eluting stents (DES). We hypothesized that mechanical stress imposed on the stent edge would cause vessel wall injury and inflammation, which may consequently lead to edge restenosis. Methods and Results:?In total, 1,496 patients were implanted with a sirolimus-eluting stent (SES), paclitaxel-eluting stent (PES) or zotarolimus-eluting stent (ZES) in Seoul National University Hospital between 2007 and 2009. Binary restenosis occurred in 161 lesions in 119 patients. We retrospectively compared the 3 DES with regard to the percentage of edge stent restenosis among all cases of restenosis. We also evaluated the maximal, minimal, and ? (maximal angle-minimal angle) angles. The percentage of edge restenosis was higher for SES than for ZES (37.5% vs. 16.7%, P=0.017). Maximal angle at the proximal edge was 64.82°±33.46° for 26 stents with proximal edge restenosis compared with 31.84°±31.51° for 89 stents without proximal edge restenosis (P=0.001). The ? angle was also significantly different between the 2 groups (14.81°±15.98° vs. 7.60°±8.86°, P=0.035). Similar findings were observed for distal edge restenosis. Both the maximal angle (39.09°±21.04° vs. 22.71°±22.83°, P=0.010) and ? angle (20.23°±15.39° vs. 9.18°±9.66°, P=0.016) at the distal edge were significantly different between the 2 groups. Conclusions:?Physical stress determined by angulation at the stent edge segment and biomechanical properties of the DES can be considered as one of the plausible mechanisms for edge stent restenosis.??(Circ J?2013; 77: 2928-2935).
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[Benzoxazole derivative B-98 ameliorates dextran sulfate sodium-induced acute murine colitis and the change of T cell profiles in acute murine colitis model].
Korean J Gastroenterol
PUBLISHED: 08-20-2013
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The unique role of enzyme 5-lipoxygenase (5-LO) in the production of leukotrienes makes it a therapeutic target for inflammatory bowel disease (IBD). The aim of this study was to evaluate the effects of B-98, a newly synthesized benzoxazole derivatives and a novel 5-LO inhibitor, in a mouse model of IBD induced by dextran sulfate sodium (DSS).
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Phenotypic modulation of human cardiospheres between stemness and paracrine activity, and implications for combined transplantation in cardiovascular regeneration.
Biomaterials
PUBLISHED: 08-11-2013
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As the search for new cell types for cardiovascular regeneration continues, it has become increasingly important to optimize ex vivo cell processing. We aimed to develop an optimal processing strategy for human cardiac progenitor cells. We hypothesized that enhancing the stemness potential and promoting the secretory activity for paracrine effects are mutually exclusive routes. Therefore, we investigated the two divergent cell processing methods to enhance cellular potency and humoral activity, respectively. We obtained human right ventricular tissues and sequentially generated primary cardiosphere (CS), primary CS-derived cells (PCDC) and secondary CSs. During secondary CS formation, inhibiting the ERK pathway, using selective RTK1 and TGF-? inhibitors, Oct4 increased 20 fold and VEGF was decreased. When the ERK pathway was stimulated by addition of EGF and TGF-?, VEGF expression was upregulated and Oct4 was downregulated, indicating that the ERK pathway serves a directional role for cellular potency versus paracrine capacity. Transplantation of PCDCs or secondary CSs into the infarcted heart of immunocompromised mouse showed significant angiogenic effects compared with PBS injection. Interestingly, combined transplantation of the two differently-processed, dual-purpose secondary CSs resulted in an additional increase in neovascularization. Human VEGF was primarily produced from secondary CSs under ERK stimulating conditions. Cardiomyocyte-like cells were produced from secondary CSs under ERK inhibitory conditions. These findings indicate that combined transplantation of specifically-processed human secondary CSs enhances infarct repair through the complementary enhancement of cardiopoietic regenerative and paracrine protective effect. Furthermore, these results underscore the fact that optimal cell processing methods have the potential to maximize the therapeutic benefits.
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PPAR? modulates vascular smooth muscle cell phenotype via a protein kinase G-dependent pathway and reduces neointimal hyperplasia after vascular injury.
Exp. Mol. Med.
PUBLISHED: 06-22-2013
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Vascular smooth muscle cells (VSMCs) undergo phenotypic changes in response to vascular injury such as angioplasty. Protein kinase G (PKG) has an important role in the process of VSMC phenotype switching. In this study, we examined whether rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-? agonist, could modulate VSMC phenotype through the PKG pathway to reduce neointimal hyperplasia after angioplasty. In vitro experiments showed that rosiglitazone inhibited the phenotype change of VSMCs from a contractile to a synthetic form. The platelet-derived growth factor (PDGF)-induced reduction of PKG level was reversed by rosiglitazone treatment, resulting in increased PKG activity. This increased activity of PKG resulted in phosphorylation of vasodilator-stimulated phosphoprotein at serine 239, leading to inhibited proliferation of VSMCs. Interestingly, rosiglitazone did not change the level of nitric oxide (NO) or cyclic guanosine monophosphate (cGMP), which are upstream of PKG, suggesting that rosiglitazone influences PKG itself. Chromatin immunoprecipitation assays for the PKG promoter showed that the activation of PKG by rosiglitazone was mediated by the increased binding of Sp1 on the promoter region of PKG. In vivo experiments showed that rosiglitazone significantly inhibited neointimal formation after balloon injury. Immunohistochemistry staining for calponin and thrombospondin showed that this effect of rosiglitazone was mediated by modulating VSMC phenotype. Our findings demonstrate that rosiglitazone is a potent modulator of VSMC phenotype, which is regulated by PKG. This activation of PKG by rosiglitazone results in reduced neointimal hyperplasia after angioplasty. These results provide important mechanistic insight into the cardiovascular-protective effect of PPAR?.
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Effects of education in an obesity control program for obese homemakers on body fat and flexibility in Korea.
Nurs Health Sci
PUBLISHED: 03-24-2013
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The study aims to investigate the effects of education in an obesity-control program (EOCP) on the percentage of body fat and flexibility in obese women in Korea. Women with over 30% body fat were offered EOCP between July 2012 and October 2012. The EOCP consisted of an educational program, exercise program, and counseling. The numbers of participants both in the EOCP and control group were 17. The study was analyzed by Wilcoxon signed-rank test using the Statistical Analysis System package. The EOCP participants presented statistically significant increases in the degree of forward trunk flexion, but only the percentage of the body fat showed differences within the EOCP group. The EOCP improved flexibility in obese women, and can be used in local obesity-control programs.
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Comparison of Metabolic Characteristics of Metabolically Healthy but Obese (MHO) Middle-Aged Men According to Different Criteria.
Korean J Fam Med
PUBLISHED: 01-28-2013
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To compare the prevalence and metabolic characteristics of metabolically healthy but obese (MHO) individuals according to different criteria.
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The effect of open and closed kinetic chain exercises on dynamic balance ability of normal healthy adults.
J Phys Ther Sci
PUBLISHED: 01-11-2013
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[Purpose] This study investigated the effect of open and closed kinetic chain exercise on the dynamic balance ability of healthy young adults. [Subjects] Thirty-three healthy adults participated in this study. [Methods] Subjects were randomly assigned to either an open kinetic chain exercise group (n=17) or a closed kinetic chain exercise group (n=16). Both the open kinetic chain and closed kinetic chain exercise groups performed 3 sets of exercises 3 times per week for 6 weeks. Dynamic balance was measured at the beginning and end of the 6-week training period, including anterior-posterior, medial-lateral, and total displacement of the center of pressure. [Results] Both exercise groups showed improvement in balance parameters but the improvement was only statistically significant in the closed kinetic chain group. [Conclusion] Closed kinetic chain exercise appears to be more effective at improving of dynamic balance ability than open kinetic chain exercise within a 6-week training period.
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Impact of shiftwork on irritable bowel syndrome and functional dyspepsia.
J. Korean Med. Sci.
PUBLISHED: 01-04-2013
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Disturbances in biological rhythms could lead to unfavorable health impact. This study aimed to evaluate the prevalence of functional dyspepsia (FD) and irritable bowel syndrome (IBS) in rotating shift workers, and to determine the factors that have significant association with the prevalence of FD and IBS. The research had been carried out among nurses and nursing assistants working at Ewha Womans University Mokdong Hospital between December 2010 and February 2011. The subjects completed self-reported questionnaires, including the quality of the sleep and the level of stress. The prevalence of FD and IBS defined by ROME III criteria, and factors associated the disorders in rotating shift workers were compared with those of day workers. A total of 207 subjects were included in the study with 147 rotating shift workers (71.0%), and 60 (29.0%) day workers. The prevalence of IBS in rotating shift workers was higher than that in day workers (32.7% vs 16.7%, P = 0.026). However, no significant difference in the prevalence of FD was observed between the two groups (19.7% vs 20.0%, P = 0.964). In the multivariate analysis, the risk factors for IBS were rotating shift work (OR, 2.36; 95% CI, 1.01-5.47) and poor sleep quality (OR, 4.13; 95% CI, 1.82-9.40), and the risk factors for FD were poor sleep quality (OR, 2.31; 95% CI, 1.01-5.28), and severe stress (OR, 2.19; 95% CI, 1.06-4.76). A higher prevalence of IBS among rotating shift workers could be directly associated with the circadian rhythm disturbance. The circadian rhythm disturbance may be related with the pathogenesis of IBS.
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Peroxisome proliferator-activated receptor-? activates endothelial progenitor cells to induce angio-myogenesis through matrix metallo-proteinase-9-mediated insulin-like growth factor-1 paracrine networks.
Eur. Heart J.
PUBLISHED: 09-14-2011
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The roles of peroxisome proliferator-activated receptor (PPAR)-? in vascular biology are mainly unknown. We investigated the effects of PPAR-? activation on the paracrine networks between endothelial progenitor cells (EPCs) and endothelial cells (ECs)/skeletal muscle.
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Primary adenosquamous cell carcinoma of the pancreas: a case report with a review of the Korean literature.
Korean J. Intern. Med.
PUBLISHED: 09-13-2011
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The most common pancreatic cancer is adenocarcinoma. Primary adenosquamous cell carcinoma of the pancreas is very rare and aggressive. A 46-year-old man presented with a 3-month history of dyspepsia and a 7-kg weight loss. The physical examination showed tenderness of the right upper quadrant of the abdomen. There was no jaundice. Amylase and lipase were elevated. CA 19-9 was elevated to 566.7 U/mL. Gastroduodenoscopy showed a hard ulceroinfiltrative mass with a yellowish exudate that bled readily on touch in the second portion of the duodenum. Abdominal computed tomography showed a 7.1 × 6.3-cm heterogeneously enhancing mass in the pancreatic head. The pancreatic mass had invaded the duodenum wall, gastric antrum, and gastroduodenal artery sheath. Fine-needle aspiration biopsy of the pancreatic mass revealed adenosquamous cell carcinoma, anaplastic type. We concluded that an adenosquamous cell carcinoma of pancreas had invaded the duodenal mucosa causing ulceration.
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Insulin-like growth factor-binding protein-7 functions as a potential tumor suppressor in hepatocellular carcinoma.
Clin. Cancer Res.
PUBLISHED: 09-09-2011
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Hepatocellular carcinoma (HCC) is a highly virulent malignancy with no effective treatment, thus requiring innovative and effective targeted therapies. The oncogene astrocyte-elevated gene-1 (AEG-1) plays a seminal role in hepatocarcinogenesis and profoundly downregulates insulin-like growth factor-binding protein-7 (IGFBP7). The present study focuses on analyzing potential tumor suppressor functions of IGFBP7 in HCC and the relevance of IGFBP7 downregulation in mediating AEG-1 function.
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Oncogene AEG-1 promotes glioma-induced neurodegeneration by increasing glutamate excitotoxicity.
Cancer Res.
PUBLISHED: 08-18-2011
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Aggressive tumor growth, diffuse tissue invasion, and neurodegeneration are hallmarks of malignant glioma. Although glutamate excitotoxicity is considered to play a key role in glioma-induced neurodegeneration, the mechanism(s) controlling this process is poorly understood. Astrocyte elevated gene-1 (AEG-1) is an oncogene that is overexpressed in several types of human cancers, including more than 90% of brain tumors. In addition, AEG-1 promotes gliomagenesis, particularly in the context of tumor growth and invasion, 2 primary characteristics of glioma. In the present study, we investigated the contribution of AEG-1 to glioma-induced neurodegeneration. Pearson correlation coefficient analysis in normal brain tissues and samples from glioma patients indicated a strong negative correlation between expression of AEG-1 and a primary glutamate transporter of astrocytes EAAT2. Gain- and loss-of-function studies in normal primary human fetal astrocytes and T98G glioblastoma multiforme cells revealed that AEG-1 repressed EAAT2 expression at a transcriptional level by inducing YY1 activity to inhibit CBP function as a coactivator on the EAAT2 promoter. In addition, AEG-1-mediated EAAT2 repression caused a reduction of glutamate uptake by glial cells, resulting in induction of neuronal cell death. These findings were also confirmed in samples from glioma patients showing that AEG-1 expression negatively correlated with NeuN expression. Taken together, our findings suggest that AEG-1 contributes to glioma-induced neurodegeneration, a hallmark of this fatal tumor, through regulation of EAAT2 expression.
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Tauroursodeoxycholate (TUDCA) inhibits neointimal hyperplasia by suppression of ERK via PKC?-mediated MKP-1 induction.
Cardiovasc. Res.
PUBLISHED: 08-11-2011
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Hyperplasia of vascular smooth muscle cells (VSMCs) after blood vessel injury is one of the major pathophysiological mechanisms associated with neointima. Tauroursodeoxycholate (TUDCA) is a cytoprotective agent in a variety of cells including hepatocytes as well as an inducer of apoptosis in cancer cells. In this study, we investigated whether TUDCA could prevent neointimal hyperplasia by suppressing the growth and migration of VSMCs.
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Lysophosphatidic acid 5 receptor induces activation of Na(+)/H(+) exchanger 3 via apical epidermal growth factor receptor in intestinal epithelial cells.
Am. J. Physiol., Cell Physiol.
PUBLISHED: 08-10-2011
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Na(+) absorption is a vital process present in all living organisms. We have reported previously that lysophosphatidic acid (LPA) acutely stimulates Na(+) and fluid absorption in human intestinal epithelial cells and mouse intestine by stimulation of Na(+)/H(+) exchanger 3 (NHE3) via LPA(5) receptor. In the current study, we investigated the mechanism of NHE3 activation by LPA(5) in Caco-2bbe cells. LPA(5)-dependent activation of NHE3 was blocked by mitogen-activated protein kinase kinase (MEK) inhibitor PD98059 and U0126, but not by phosphatidylinositol 3-kinase inhibitor LY294002 or phospholipase C-? inhibitor U73122. We found that LPA(5) transactivated the epidermal growth factor receptor (EGFR) and that inhibition of EGFR blocked LPA(5)-dependent activation of NHE3, suggesting an obligatory role of EGFR in the NHE3 regulation. Confocal immunofluorescence and surface biotinylation analyses showed that LPA(5) was located mostly in the apical membrane. EGFR, on the other hand, showed higher expression in the basolateral membrane. However, inhibition of apical EGFR, but not basolateral EGFR, abrogated LPA-induced regulation of MEK and NHE3, indicating that LPA(5) selectively activates apical EGFR. Furthermore, transactivation of EGFR independently activated the MEK-ERK pathway and proline-rich tyrosine kinase 2 (Pyk2). Similarly to MEK inhibition, knockdown of Pyk2 blocked activation of NHE3 by LPA. Furthermore, we showed that RhoA and Rho-associated kinase (ROCK) are involved in activation of Pyk2. Interestingly, LPA(5) did not directly activate RhoA but was required for transactivation of EGFR. Together, these results unveil a pivotal role of apical EGFR in NHE3 regulation by LPA and show that the RhoA-ROCK-Pyk2 and MEK-ERK pathways converge onto NHE3.
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[Clinicopathological characteristics of gastric cancer and survival improvement by surgical treatment in the elderly].
Korean J Gastroenterol
PUBLISHED: 07-23-2011
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It has been known that elderly patients with gastric cancer show worse general condition and higher comorbidities. Therefore, few elderly patients undergo surgery. This study was designed to determine clinicopathological characteristics of gastric cancer in elderly patients and evaluate their survival improvements by the surgical treatment.
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Peroxisome proliferator-activated receptor-gamma agonists suppress tissue factor overexpression in rat balloon injury model with paclitaxel infusion.
PLoS ONE
PUBLISHED: 07-07-2011
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The role and underlying mechanisms of rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-?) agonist, on myocardial infarction are poorly understood. We investigated the effects of this PPAR-? agonist on the expression of tissue factor (TF), a primary molecule for thrombosis, and elucidated its underlying mechanisms. The PPAR-? agonist inhibited TF expression in response to TNF-? in human umbilical vein endothelial cells, human monocytic leukemia cell line, and human umbilical arterial smooth muscle cells. The overexpression of TF was mediated by increased phosphorylation of mitogen-activated protein kinase (MAPK), which was blocked by the PPAR-? agonist. The effective MAPK differed depending on each cell type. Luciferase and ChIP assays showed that transcription factor, activator protein-1 (AP-1), was a pivotal target of the PPAR-? agonist to lower TF transcription. Intriguingly, two main drugs for drug-eluting stent, paclitaxel or rapamycin, significantly exaggerated thrombin-induced TF expression, which was also effectively blocked by the PPAR-? agonist in all cell types. This PPAR-? agonist did not impair TF pathway inhibitor (TFPI) in three cell types. In rat balloon injury model (Sprague-Dawley rats, n?=?10/group) with continuous paclitaxel infusion, the PPAR-? agonist attenuated TF expression by 70±5% (n?=?4; P<0.0001) in injured vasculature. Taken together, rosiglitazone reduced TF expression in three critical cell types involved in vascular thrombus formation via MAPK and AP-1 inhibitions. Also, this PPAR-? agonist reversed the paclitaxel-induced aggravation of TF expression, which suggests a possibility that the benefits might outweigh its risks in a group of patients with paclitaxel-eluting stent implanted.
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The poly-?-D-glutamic acid capsule of Bacillus anthracis enhances lethal toxin activity.
Infect. Immun.
PUBLISHED: 06-20-2011
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The poly-?-D-glutamic acid (PGA) capsule is one of the major virulence factors of Bacillus anthracis, which causes a highly lethal infectious disease. The PGA capsule disguises B. anthracis from immune surveillance and allows its unimpeded growth in the host. The PGA capsule recently was reported to be associated with lethal toxin (LT) in the blood of experimentally infected animals (M. H. Cho, et al., Infect. Immun. 78:387-392, 2010). The effect of PGA, either alone or in combination with LT, on macrophages, which play an important role in the progression of anthrax disease, has not been thoroughly investigated. In this study, we investigated the effect of PGA on LT cytotoxicity using the mouse macrophage cell line J774A.1. PGA produced a concentration-dependent enhancement of the cytotoxicity of LT on J774A.1 cells through an enhancement in the binding and accumulation of protective antigen to its receptors. The increase of LT activity was confirmed using Western blot analysis, which showed that the combination of PGA and LT produced a greater degree of degradation of mitogen-activated protein kinase kinases and an increased level of the activation of the proform of caspase-1 to its processed form compared to the effects of LT alone. In addition, mice that received a tail vein injection of both PGA and LT had a significantly increased rate of death compared to that of mice injected with LT alone. PGA had no effect when added to cultures or administered to mice in the absence of LT. These results emphasize the importance of PGA in the pathogenesis of anthrax infection.
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Increased RNA-induced silencing complex (RISC) activity contributes to hepatocellular carcinoma.
Hepatology
PUBLISHED: 04-27-2011
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There is virtually no effective treatment for advanced hepatocellular carcinoma (HCC) and novel targets need to be identified to develop effective treatment. We recently documented that the oncogene Astrocyte elevated gene-1 (AEG-1) plays a seminal role in hepatocarcinogenesis. Employing yeast two-hybrid assay and coimmunoprecipitation followed by mass spectrometry, we identified staphylococcal nuclease domain containing 1 (SND1), a nuclease in the RNA-induced silencing complex (RISC) facilitating RNAi-mediated gene silencing, as an AEG-1 interacting protein. Coimmunoprecipitation and colocalization studies confirmed that AEG-1 is also a component of RISC and both AEG-1 and SND1 are required for optimum RISC activity facilitating small interfering RNA (siRNA) and micro RNA (miRNA)-mediated silencing of luciferase reporter gene. In 109 human HCC samples SND1 was overexpressed in ?74% cases compared to normal liver. Correspondingly, significantly higher RISC activity was observed in human HCC cells compared to immortal normal hepatocytes. Increased RISC activity, conferred by AEG-1 or SND1, resulted in increased degradation of tumor suppressor messenger RNAs (mRNAs) that are target of oncomiRs. Inhibition of enzymatic activity of SND1 significantly inhibited proliferation of human HCC cells. As a corollary, stable overexpression of SND1 augmented and siRNA-mediated inhibition of SND1 abrogated growth of human HCC cells in vitro and in vivo, thus revealing a potential role of SND1 in hepatocarcinogenesis.
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[The effect of aspirin alone or aspirin plus additional antiplatelets therapy on upper gastrointestinal hemorrhage].
Korean J Gastroenterol
PUBLISHED: 04-27-2011
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The increasing incidence of cardiovascular disease has led to an increase in the frequency of upper gastrointestinal (GI) hemorrhage due to the use of antiplatelet agents. This study examined the clinical characteristics of patients with upper GI hemorrhage who were administered aspirin alone or a combination treatment of antiplatelet agents.
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Associations between single nucleotide polymorphisms of MMP2, VEGF, and HIF1A genes and the risk of developing colorectal cancer.
Anticancer Res.
PUBLISHED: 03-08-2011
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The aim of this study was to investigate the association between the risk for colorectal cancer and single nucleotide polymorphisms (SNP) of matrix metalloproteinase-2 (MMP2) -1306C/T, vascular endothelial growth factor (VEGF) 936C/T and hypoxia inducible factor-1? (HIF1A) 1772C/T.
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c-Met activation through a novel pathway involving osteopontin mediates oncogenesis by the transcription factor LSF.
J. Hepatol.
PUBLISHED: 02-17-2011
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Understanding the molecular pathogenesis of hepatocellular carcinoma (HCC) would facilitate development of targeted and effective therapies for this fatal disease. We recently demonstrated that the cellular transcription factor Late SV40 Factor (LSF) is overexpressed in more than 90% of human HCC cases, compared to the normal liver, and plays a seminal role in hepatocarcinogenesis. LSF transcriptionally upregulates osteopontin (OPN) that plays a significant role in mediating the oncogenic function of LSF. The present study aims at a better understanding of LSF function by analyzing the signaling pathway modulated by LSF.
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The Vibrio cholerae VarS/VarA two-component system controls the expression of virulence proteins through ToxT regulation.
Microbiology (Reading, Engl.)
PUBLISHED: 02-17-2011
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Although the conditions for inducing virulence protein expression in vitro are different, both classical and El Tor biotypes of Vibrio cholerae have been reported to regulate the expression of virulence proteins such as cholera toxin (CT) and toxin-coregulated pili (Tcp) through the ToxR/S/T system. The transcription activator ToxR responds to environmental stimuli such as pH and temperature and activates the second transcriptional regulator ToxT, which upregulates expression of virulence proteins. In addition to the ToxR/S/T signalling system, V. cholerae has been proposed to utilize another two-component system VarS/VarA to modulate expression of virulence genes. Previous study has shown that VarA of the VarS/VarA system is involved in the regulation of virulence proteins in the classical V. cholerae O395 strain; however, no further analysis was performed concerning VarS. In this study, we constructed varS mutants derived from the classical O395 and El Tor C6706 strains and demonstrated that VarS is also involved in the expression of the virulence proteins CT and Tcp from the V. cholerae classical and El Tor strains. This expression is through regulation of ToxT expression in response to environmental changes due to different toxin-inducing conditions.
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Analysis of differential proteomes of induced pluripotent stem cells by protein-based reprogramming of fibroblasts.
J. Proteome Res.
PUBLISHED: 02-04-2011
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The recent generation of induced pluripotent stem (iPS) cells represents a novel opportunity to complement embryonic stem (ES) cell-based approaches. iPS cells can be generated by viral transduction of specific transcription factors, but there is a potential risk of tumorigenicity by random retroviral integration. We have generated novel iPS (sFB-protein-iPS) cells from murine dermal fibroblasts (FVB-sFB) that have ES cell characteristics, using ES cell-derived cell extracts instead of performing viral transduction. Notably, only cell extracts from an ES cell line (C57-mES) on the C57/BL6 background generated iPS cells in our protocol-not an ES cell line (E14-mES) on the 129 background. Hypothesizing that determining the differences in these 2 mES cell lines will provide vital insight into the reprogramming machinery, we performed proteomic and global gene expression analysis by iTRAQ and mRNA microarray, respectively. We observed that pluripotent ES cells and ES cell extract-derived iPS cells had differential proteomes and global gene expression patterns. Notably, reprogramming-competent C57-mES cells highly expressed proteins that regulate protein synthesis and metabolism, compared with reprogramming-incompetent 129-mES cells, suggesting that there is a threshold that protein synthetic machinery must exceed to initiate reprogramming.
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Astrocyte elevated gene-1 (AEG-1): A multifunctional regulator of normal and abnormal physiology.
Pharmacol. Ther.
PUBLISHED: 01-03-2011
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Since its initial identification and cloning in 2002, Astrocyte Elevated Gene-1 (AEG-1), also known as metadherin (MTDH), 3D3 and LYsine-RIch CEACAM1 co-isolated (LYRIC), has emerged as an important oncogene that is overexpressed in all cancers analyzed so far. Examination of a large cohort of patient samples representing diverse cancer indications has revealed progressive increase in AEG-1 expression with stages and grades of the disease and an inverse relationship between AEG-1 expression level and patient prognosis. AEG-1 functions as a bona fide oncogene by promoting transformation. In addition, it plays a significant role in invasion, metastasis, angiogenesis and chemoresistance, all important hallmarks of an aggressive cancer. AEG-1 is also implicated in diverse physiological and pathological processes, such as development, inflammation, neurodegeneration, migraine and Huntingtons disease. AEG-1 is a highly basic protein with a transmembrane domain and multiple nuclear localization signals and it is present in the cell membrane, cytoplasm, nucleus, nucleolus and endoplasmic reticulum. In each location, AEG-1 interacts with specific proteins thereby modulating diverse intracellular processes the combination of which contributes to its pleiotrophic properties. The present review provides a snapshot of the current literature along with future perspectives on this unique molecule.
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BORIS/CTCFL-mediated transcriptional regulation of the hTERT telomerase gene in testicular and ovarian tumor cells.
Nucleic Acids Res.
PUBLISHED: 09-28-2010
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Telomerase activity, not detectable in somatic cells but frequently activated during carcinogenesis, confers immortality to tumors. Mechanisms governing expression of the catalytic subunit hTERT, the limiting factor for telomerase activity, still remain unclear. We previously proposed a model in which the binding of the transcription factor CTCF to the two first exons of hTERT results in transcriptional inhibition in normal cells. This inhibition is abrogated, however, by methylation of CTCF binding sites in 85% of tumors. Here, we showed that hTERT was unmethylated in testicular and ovarian tumors and in derivative cell lines. We demonstrated that CTCF and its paralogue, BORIS/CTCFL, were both present in the nucleus of the same cancer cells and bound to the first exon of hTERT in vivo. Moreover, exogenous BORIS expression in normal BORIS-negative cells was sufficient to activate hTERT transcription with an increasing number of cell passages. Thus, expression of BORIS was sufficient to allow hTERT transcription in normal cells and to counteract the inhibitory effect of CTCF in testicular and ovarian tumor cells. These results define an important contribution of BORIS to immortalization during tumorigenesis.
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An outbreak of type C botulism in waterbirds: Incheon, Korea.
J. Wildl. Dis.
PUBLISHED: 08-07-2010
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Five outbreaks of botulism in waterbirds were encountered over a 5-yr period from 2004 to 2008 in Korea. In October 2008, an outbreak of avian type C botulism affected approximately 2,000 wild waterbirds in the Namdong flood control basin, Incheon, South Korea. Ecologic conditions, clinical signs exhibited by moribund birds, and lack of gross pathology and microbial evidence of infectious disease, suggested botulinum intoxication. Type C botulinum toxin was demonstrated in duck sera, liquid culture of intestinal tissue, and an extract of maggots taken from the carcasses. Additionally, 34 of 40 (85.0%) sediment samples from the same area were positive for botulinum toxin by mouse bioassay using multivalent (types A-F) antiserum, indicating that toxigenic Clostridium botulinum was present in the environment. This is the most severe case of avian botulism documented in Korea.
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Selection and characterization of cellulose-deficient derivates of shiga toxin-producing Escherichia coli.
J. Food Prot.
PUBLISHED: 06-12-2010
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Shiga toxin-producing Escherichia coli (STEC) is known to have several defense mechanisms, one of which is the production of extracellular substances including cellulose. The goal of this study was to prepare pairs of STEC cultures for use in future studies designed to address the role of cellulose in protecting the cells of STEC for survival under adverse environmental conditions. Cells of STEC deficient in cellulose production were separated from cellulose-proficient wild-type cells. The identities of the two types of cells were confirmed using serotyping and pulsed-field gel electrophoresis (PFGE). Selected growth characteristics of the two types of cells were determined using three phenotype microarray plates, PM9, PM10, and PM11. The cellulose-deficient and cellulose-proficient cells in each STEC pair shared the same serotype and PFGE profile. The deficiency in cellulose production did not significantly (P > 0.05) affect the growth characteristics of STEC cells under 191 of the 210 tested growth conditions. Significant differences in growth between the two types of cells were observed only in the presence of two antibiotics, a short chain fatty acid, and high concentrations of osmolytes, as well as under extreme acidic and alkaline pH. These results suggest that deficiency in cellulose production did not alter the serological property, PFGE profile, and growth characteristics of selected STEC strains under optimal growth conditions. The STEC strains and their cellulose-deficient derivates could be useful for studying the role of cellulose in protecting the cells of STEC for survival under adverse environmental conditions.
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Induction of pluripotent stem cells from adult somatic cells by protein-based reprogramming without genetic manipulation.
Blood
PUBLISHED: 05-03-2010
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The concept of reprogramming of somatic cells has opened a new era in regenerative medicine. Transduction of defined factors has successfully achieved pluripotency. However, during the generation process of induced pluripotent stem (iPS) cells, genetic manipulation of certain factors may cause tumorigenicity, which limits further application. We report that that a single transfer of embryonic stem (ES) cell-derived proteins into primarily cultured adult mouse fibroblasts, rather than repeated transfer or prolonged exposure to materials, can achieve full reprogramming up to the pluripotent state without the forced expression of ectopic transgenes. During the process, gene expression and epigenetic status were converted from somatic to ES-equivalent status. We verified that protein-based reprogramming was neither by the contamination of protein donor ES cell nor by DNA/RNA from donor ES cell. Protein-iPS cells were biologically and functionally very similar to ES cells and differentiated into 3 germ layers in vitro. Furthermore, protein-iPS cells possessed in vivo differentiation (well-differentiated teratoma formation) and development (chimeric mice generation and a tetraploid blastocyst complementation) potentials. Our results provide an alternative and safe strategy for the reprogramming of somatic cells that can be used to facilitate pluripotent stem cell-based cell therapy.
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Transcription factor Late SV40 Factor (LSF) functions as an oncogene in hepatocellular carcinoma.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 04-19-2010
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Hepatocellular carcinoma (HCC) is a highly aggressive cancer with no currently available effective treatment. Understanding of the molecular mechanism of HCC development and progression is imperative for developing novel, effective, and targeted therapies for this lethal disease. In this article, we document that the cellular transcription factor Late SV40 Factor (LSF) plays an important role in HCC pathogenesis. LSF protein was significantly overexpressed in human HCC cells compared to normal hepatocytes. In 109 HCC patients, LSF protein was overexpressed in >90% cases, compared to normal liver, and LSF expression level showed significant correlation with the stages and grades of the disease. Forced overexpression of LSF in less aggressive HCC cells resulted in highly aggressive, angiogenic, and multiorgan metastatic tumors in nude mice. Conversely, inhibition of LSF significantly abrogated growth and metastasis of highly aggressive HCC cells in nude mice. Microarray studies revealed that as a transcription factor, LSF modulated specific genes regulating invasion, angiogenesis, chemoresistance, and senescence. The expression of osteopontin (OPN), a gene regulating every step in tumor progression and metastasis, was robustly up-regulated by LSF. It was documented that LSF transcriptionally up-regulates OPN, and loss-of-function studies demonstrated that OPN plays an important role in mediating the oncogenic functions of LSF. Together, these data establish a regulatory role of LSF in cancer, particularly HCC pathogenesis, and validate LSF as a viable target for therapeutic intervention.
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[Analysis of risk factors for low bone mineral density in patients with inflammatory bowel disease].
Korean J Gastroenterol
PUBLISHED: 04-15-2010
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Several clinical risk factors for low bone mineral density (BMD) in the patients with inflammatory bowel disease (IBD) have been suggested. However, its prevalence and pathophysiology in Korean population have not been fully studied. The aim of this study was to investigate the prevalence and risk factors for low BMD in Korean IBD patient.
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Molecular mechanism of chemoresistance by astrocyte elevated gene-1.
Cancer Res.
PUBLISHED: 04-13-2010
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Our recent findings show that astrocyte elevated gene-1 (AEG-1) is overexpressed in >90% of human hepatocellular carcinoma (HCC) samples, and AEG-1 plays a central role in regulating development and progression of HCC. In the present study, we elucidate a molecular mechanism of AEG-1-induced chemoresistance, an important characteristic of aggressive cancers. AEG-1 increases the expression of multidrug resistance gene 1 (MDR1) protein, resulting in increased efflux and decreased accumulation of doxorubicin, promoting doxorubicin resistance. Suppression of MDR1 by small interfering RNA or chemical reagents, or inhibition of AEG-1 or a combination of both genes, significantly increases in vitro sensitivity to doxorubicin. In nude mice xenograft studies, a lentivirus expressing AEG-1 short hairpin RNA, in combination with doxorubicin, profoundly inhibited growth of aggressive human HCC cells compared with either agent alone. We document that although AEG-1 does not affect MDR1 gene transcription, it facilitates association of MDR1 mRNA to polysomes, resulting in increased translation, and AEG-1 also inhibits ubiquitination and subsequent proteasome-mediated degradation of MDR1 protein. This study is the first documentation of a unique aspect of AEG-1 function (i.e., translational and posttranslational regulation of proteins). Inhibition of AEG-1 might provide a means of more effectively using chemotherapy to treat HCC, which displays inherent chemoresistance with aggressive pathology.
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Regulation of hemagglutinin/protease expression by the VarS/VarA-CsrA/B/C/D system in Vibrio cholerae.
Microb. Pathog.
PUBLISHED: 03-04-2010
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In this study, through the analysis of Vibrio cholerae 2740-80 mutant strains produced by the cholera toxin subunit B gene containing Mariner-based transposon, we found that disruption of the varS gene, a member of the recently reported sensory system VarS/VarA-CsrA/B/C/D, resulted in altered expression of hemagglutinin/protease A. To further investigate the connection between VarS and HapA, we generated an additional varS mutant, V. cholerae 2740-80-VS, and examined the effect of this mutation on expression of HapA and of genes in the VarS/VarA-CsrA/B/C/D system. 2740-80-VS showed decreased expression of varS, csrB/C, hapR, and hapA along with increased biofilm production. Interestingly, expression of the alternative sigma factor sigma(s), which is important for adaptation to environmental stress, was also decreased in this mutant. These results indicate that the VarS/VarA-CsrA/B/C/D system is involved in the control of HapA expression and biofilm production in V. cholerae 2740-80 through HapR regulation, and also that VarS/VarA controls expression of sigma(s) for HapA regulation.
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Expression patterns of astrocyte elevated gene-1 (AEG-1) during development of the mouse embryo.
Gene Expr. Patterns
PUBLISHED: 01-06-2010
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Expression of astrocyte elevated gene-1 (AEG-1) is elevated in multiple human cancers including brain tumors, neuroblastomas, melanomas, breast cancers, non-small cell lung cancers, liver cancers, prostate cancers, and esophageal cancers. This gene plays crucial roles in tumor cell growth, invasion, angiogenesis and progression to metastasis. In addition, over-expression of AEG-1 protects primary and transformed cells from apoptosis-inducing signals by activating PI3K-Akt signaling pathways. These results suggest that AEG-1 is intimately involved in tumorigenesis and may serve as a potential therapeutic target for various human cancers. However, the normal physiological functions of AEG-1 require clarification. We presently analyzed the expression pattern of AEG-1 during mouse development. AEG-1 was expressed in mid-to-hindbrain, fronto-nasal processes, limbs, and pharyngeal arches in the early developmental period from E8.5 to E9.5. In addition, at stages of E12.5-E18.5 AEG-1 was localized in the brain, and olfactory and skeletal systems suggesting a role in neurogenesis, as well as in skin, including hair follicles, and in the liver, which are organ sites in which AEG-1 has been implicated in tumor development and progression. AEG-1 co-localized with Ki-67, indicating a role in cell proliferation, as previously revealed in tumorigenesis. Taken together, these results suggest that AEG-1 may play a prominent role during normal mouse development in the context of cell proliferation as well as differentiation, and that temporal regulation of AEG-1 expression may be required during specific stages and in specific tissues during development.
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Astrocyte elevated gene-1: a novel target for human glioma therapy.
Mol. Cancer Ther.
PUBLISHED: 01-06-2010
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Malignant gliomas including glioblastoma multiforme (GBM) and anaplastic astrocytomas are the most common primary brain tumors. Despite multimodal treatment including surgery, chemotherapy, and radiation, median survival for patients with GBMs is only 12 to 15 months. Identifying molecules critical for glioma progression is crucial for devising effective targeted therapy. In the present study, we investigated the potential contribution of astrocyte elevated gene-1 (AEG-1) in gliomagenesis and explored the possibility of AEG-1 as a therapeutic target for malignant glioma. We analyzed the expression levels of AEG-1 in 9 normal brain tissues and 98 brain tumor patient samples by Western blot analysis and immunohistochemistry. AEG-1 expression was significantly elevated in >90% of diverse human brain tumor samples including GBMs and astrocytic tumors, and also in human glioma cell lines compared with normal brain tissues and normal astrocytes. Knockdown of AEG-1 by small interfering RNA inhibited cell viability, cloning efficiency, and invasive ability of U87 human glioma cells and 9L rat gliosarcoma cells. We also found that matrix metalloproteases (MMP-2 and MMP-9) are involved in AEG-1-mediated invasion of glioma cells. In an orthotopic nude mouse brain tumor model using primary human GBM12 tumor cells, AEG-1 small interfering RNA significantly suppressed glioma cell growth in vivo. Taken together, these provocative results indicate that AEG-1 may play a crucial role in the pathogenesis of glioma and that AEG-1 could represent a viable potential target for malignant glioma therapy.
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Infectious mononucleosis hepatitis in young adults: two case reports.
Korean J. Intern. Med.
PUBLISHED: 11-27-2009
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Infectious mononucleosis due to Epstein-Barr virus (EBV) infection sometimes causes acute hepatitis, which is usually self-limiting with mildly elevated transaminases, but rarely with jaundice. Primary EBV infection in children is usually asymptomatic, but in a small number of healthy individuals, typically young adults, EBV infection results in a clinical syndrome of infectious mononucleosis with hepatitis, with typical symptoms of fever, pharyngitis, lymphadenopathy, and hepatosplenomegaly. EBV is rather uncommonly confirmed as an etiologic agent of acute hepatitis in adults. Here, we report two cases: the first case with acute hepatitis secondary to infectious mononucleosis and a second case, with acute hepatitis secondary to infectious mononucleosis concomitantly infected with hepatitis A. Both cases involved young adults presenting with fever, pharyngitis, lymphadenopathy, hepatosplenomegaly, and atypical lymphocytosis confirmed by serologic tests, liver biopsy and electron microscopic study.
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Astrocyte elevated gene-1: far more than just a gene regulated in astrocytes.
Cancer Res.
PUBLISHED: 11-10-2009
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Since its original cloning by subtraction hybridization in 2002, it is now evident that Astrocyte elevated gene-1 (AEG-1) is a key contributor to the carcinogenic process in diverse organs. AEG-1 protein expression is elevated in advanced stages of many cancers, which correlates with poor survival. In specific cancers, such as breast and liver cancer, the AEG-1 gene itself is amplified, further supporting a seminal role in tumorigenesis. Overexpression and inhibition studies both in in vitro and in in vivo models reveal the importance of AEG-1 in regulating multiple physiologically and pathologically relevant processes including proliferation, invasion, metastasis, and gene expression. AEG-1 is a single-pass transmembrane protein with multiple nuclear localization signals and no known domains or motifs. Although pertinent roles of AEG-1 in the carcinogenic process are established, its potential function (promotion of metastasis only versus functioning as a bona fide oncogene) as well as localization (cell surface versus nucleus) remain areas requiring further clarification. The present review critically evaluates what is currently known about AEG-1 and provides new perspectives relative to this intriguing molecule that may provide a rational target for intervening in the cancer phenotype.
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Identification of genes conferring resistance to 5-fluorouracil.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 07-21-2009
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Astrocyte elevated gene-1 (AEG-1) is overexpressed in >90% of human hepatocellular carcinoma (HCC) patients and plays a significant role in mediating aggressive progression of HCC. AEG-1 is known to augment invasion, metastasis, and angiogenesis, and we now demonstrate that AEG-1 directly contributes to another important hallmark of aggressive cancers, that is, resistance to chemotherapeutic drugs, such as 5-fluorouracil (5-FU). AEG-1 augments expression of the transcription factor LSF that regulates the expression of thymidylate synthase (TS), a target of 5-FU. In addition, AEG-1 enhances the expression of dihydropyrimidine dehydrogenase (DPYD) that catalyzes the initial and rate-limiting step in the catabolism of 5-FU. siRNA-mediated inhibition of AEG-1, LSF, or DPYD significantly increased the sensitivity of HCC cells to 5-FU in vitro and a lentivirus delivering AEG-1 siRNA in combination with 5-FU markedly inhibited growth of HCC cells xenotransplanted in athymic nude mice when compared to either agent alone. The present studies highlight 2 previously unidentified genes, AEG-1 and LSF, contributing to chemoresistance. Inhibition of AEG-1 might be exploited as a therapeutic strategy along with 5-FU-based combinatorial chemotherapy for HCC, a highly fatal cancer with currently very limited therapeutic options.
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The clinicopathological significance of tissue levels of hypoxia-inducible factor-1alpha and vascular endothelial growth factor in gastric cancer.
Gut Liver
PUBLISHED: 06-30-2009
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Hypoxia-inducible factor-1alpha (HIF-1alpha) is a mediator of tumor progression. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor known to be induced by HIF-1alpha. We investigated the clinicopathological significance of HIF-1alpha and VEGF levels in biopsied gastric cancer tissue.
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[Comparison of clinical characteristics and outcomes between geriatric and non-geriatric patients in peptic ulcer bleeding].
Korean J Gastroenterol
PUBLISHED: 05-22-2009
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In geriatric patients with peptic ulcer, the use of NSAID and prevalence of chronic illness have been increased, but the Helicobacter pylori (H. pylori) infected portion decreased. The aim of this study was to evaluate the clinical characteristics and outcomes of geriatric patients (aged 65 or older) with peptic ulcer bleeding and compare with non-geriatric patients (less than 65 years old).
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Influence of culture conditions and medium composition on the production of cellulose by shiga toxin-producing Escherichia coli cells.
Appl. Environ. Microbiol.
PUBLISHED: 05-01-2009
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Culture conditions favoring cellulose production by Shiga toxin-producing Escherichia coli included a 28 degrees C incubation temperature, an aerobic atmosphere, and the presence of 2% ethanol in Luria-Bertani no-salt agar with pH 6.0 and a water activity of 0.99. These findings will assist in formulating microbiological media useful for cellulose and biofilm research.
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The prevalence and clinical characteristics of reflux esophagitis in koreans and its possible relation to metabolic syndrome.
J. Korean Med. Sci.
PUBLISHED: 04-20-2009
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The prevalence of reflux esophagitis is increasing in Korea. To estimate the prevalence and clinical characteristics of reflux esophagitis in healthy subjects, we retrospectively examined the medical records of healthy subjects undergoing a routine check-up from October 2004 to September 2005. A total of 6,082 (3,590 men, mean age 44+/-10 yr) subjects were enrolled in this study. The prevalence of reflux esophagitis in healthy subjects was 10.5%. According to the univariate analysis, male sex (odds ratio [OR] 3.49, 95% confidence interval [CI] 2.84-4.30), smoking history (OR 1.91, 95% CI 1.60-2.28), body mass index (BMI) >30 kg/m(2) (OR 2.13, 95% CI 1.37-3.33), total cholesterol >250 mg/dL (OR 1.50, 95% CI 1.05-2.14), low-density lipoprotein (LDL) cholesterol >/=160 mg/dL (OR 1.52, 95% CI 1.08-2.14), triglyceride >/=150 mg/dL (OR 1.92, 95% CI 1.61-2.30), high blood pressure (BP) (OR 1.46, 95% CI 1.20-1.76), and fasting glucose >/=110 mg/dL (OR 1.45, 95% CI 1.13-1.86) were significantly associated with reflux esophagitis (all p<0.05). However, age, alcohol drinking and Helicobacter pylori infection were not associated with reflux esophagitis. In conclusion, significant relationships of reflux esophagitis with obesity, low high-density lipoprotein (HDL) cholesterol, high triglyceride, high BP, and elevated fasting glucose suggested that reflux esophagitis might represent the disease spectrum of the metabolic syndrome.
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Sulfasalazine induces haem oxygenase-1 via ROS-dependent Nrf2 signalling, leading to control of neointimal hyperplasia.
Cardiovasc. Res.
PUBLISHED: 02-21-2009
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Inflammation, and the subsequent proliferative activity of vascular smooth muscle cells (VSMCs), is one of the major pathophysiological mechanisms associated with neointimal hyperplasia following vascular injury. Although sulfasalazine (SSZ) has been used as an anti-inflammatory and immune-modulatory agent in various inflammatory diseases, its primary targets and therapeutic effects on vascular disease have not yet been determined. We investigated whether SSZ could suppress VSMC growth and prevent neointimal hyperplasia.
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Astrocyte elevated gene-1 regulates hepatocellular carcinoma development and progression.
J. Clin. Invest.
PUBLISHED: 02-16-2009
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Hepatocellular carcinoma (HCC) is a highly aggressive vascular cancer characterized by diverse etiology, activation of multiple signal transduction pathways, and various gene mutations. Here, we have determined a specific role for astrocyte elevated gene-1 (AEG1) in HCC pathogenesis. Expression of AEG1 was extremely low in human hepatocytes, but its levels were significantly increased in human HCC. Stable overexpression of AEG1 converted nontumorigenic human HCC cells into highly aggressive vascular tumors, and inhibition of AEG1 abrogated tumorigenesis by aggressive HCC cells in a xenograft model of nude mice. In human HCC, AEG1 overexpression was associated with elevated copy numbers. Microarray analysis revealed that AEG1 modulated the expression of genes associated with invasion, metastasis, chemoresistance, angiogenesis, and senescence. AEG1 also was found to activate Wnt/beta-catenin signaling via ERK42/44 activation and upregulated lymphoid-enhancing factor 1/T cell factor 1 (LEF1/TCF1), the ultimate executor of the Wnt pathway, important for HCC progression. Inhibition studies further demonstrated that activation of Wnt signaling played a key role in mediating AEG1 function. AEG1 also activated the NF-kappaB pathway, which may play a role in the chronic inflammatory changes preceding HCC development. These data indicate that AEG1 plays a central role in regulating diverse aspects of HCC pathogenesis. Targeted inhibition of AEG1 might lead to the shutdown of key elemental characteristics of HCC and could lead to an effective therapeutic strategy for HCC.
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New mechanism of rosiglitazone to reduce neointimal hyperplasia: activation of glycogen synthase kinase-3beta followed by inhibition of MMP-9.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 02-05-2009
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Mechanism of neointimal hyperplasia after vascular injury includes activation of signaling pathways and matrix metalloproteinases (MMPs) that are involved in cell proliferation and migration. Rosiglitazone, a synthetic peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, was reported to inhibit neointimal hyperplasia in diabetic animals and humans. But the underlying mechanism has not been clarified. In this study, we examined how rosiglitazone inhibited neointimal hyperplasia.
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Human gamma-satellite DNA maintains open chromatin structure and protects a transgene from epigenetic silencing.
Genome Res.
PUBLISHED: 01-13-2009
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The role of repetitive DNA sequences in pericentromeric regions with respect to kinetochore/heterochromatin structure and function is poorly understood. Here, we use a mouse erythroleukemia cell (MEL) system for studying how repetitive DNA assumes or is assembled into different chromatin structures. We show that human gamma-satellite DNA arrays allow a transcriptionally permissive chromatin conformation in an adjacent transgene and efficiently protect it from epigenetic silencing. These arrays contain CTCF and Ikaros binding sites. In MEL cells, this gamma-satellite DNA activity depends on binding of Ikaros proteins involved in differentiation along the hematopoietic pathway. Given our discovery of gamma-satellite DNA in pericentromeric regions of most human chromosomes and a dynamic chromatin state of gamma-satellite arrays in their natural location, we suggest that gamma-satellite DNA represents a unique region of the functional centromere with a possible role in preventing heterochromatin spreading beyond the pericentromeric region.
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Expression and characterization of an iron-containing superoxide dismutase from Burkholderia pseudomallei.
J. Microbiol.
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A superoxide dismutase (SOD) gene from Burkholderia pseudomallei, the causative agent of melioidosis, was cloned and expressed in Escherichia coli, and its product was functionally and physically characterized. The gene has an open-reading frame of 579 bp. The deduced amino acid sequence has 192 residues with a calculated molecular mass of ~22 kDa. Sequence comparison with other bacterial SODs showed that the protein contains typical metal-binding motifs and other Fe-SOD-conserved residues. The sequence has substantial similarity with other bacterial Fe-SOD sequences. The enzymatic activity of the expressed protein was inhibited by hydrogen peroxide but not by sodium azide or potassium cyanide, attributes that indeed are characteristic of typical bacterial Fe-SODs. Western blotting with antiserum against the recombinant Fe-SOD revealed that it is expressed in B. pseudomallei. Transformed E. coli that expressed the Fe-SOD had significantly increased SOD activity and was highly tolerant to paraquat-mediated replication inhibition, compared to transformed cells carrying an empty vector. Our results provide a basis for further biochemical characterization of the enzyme and elucidation of its role in the pathogenesis of B. pseudomallei.
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Generation of human secondary cardiospheres as a potent cell processing strategy for cell-based cardiac repair.
Biomaterials
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Cell therapy is a promising approach for repairing damaged heart. However, there are large rooms to be improved in therapeutic efficacy. We cultured a small quantity (5-10 mg) of heart biopsy tissues from 16 patients who received heart transplantation. We produced primary and secondary cardiospheres (CSs) using repeated three-dimensional culture strategy and characterized the cells. Approximately 5000 secondary CSs were acquired after 45 days. Genetic analysis confirmed that the progenitor cells in the secondary CSs originated from the innate heart, but not from extra-cardiac organs. The expressions of Oct4 and Nanog were significantly induced in secondary CSs compared with adherent cells derived from primary CSs. Those expressions in secondary CSs were higher in a cytokine-deprived medium than in a cytokine-supplemented one, suggesting that formation of the three-dimensional structure was important to enhance stemness whereas supplementation with various cytokines was not essential. Signal blocking experiments showed that the ERK and VEGF pathways are indispensable for sphere formation. To optimize cell processing, we compared four different methods of generating spheres. Method based on the hanging-drop or AggreWell™ was superior to that based on the poly-d-lysine-coated dish or Petri dish with respect to homogeneity of the product, cellular potency and overall simplicity of the process. When transplanted into the ischemic myocardium of immunocompromised mice, human secondary CSs differentiated into cardiomyocytes and endothelial cells. These results demonstrate that generation of secondary CSs from a small quantity of adult human cardiac tissue is a feasible and effective cell processing strategy to improve the therapeutic efficacy of cell therapy.
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Significance of preoperative tissue levels of vascular-endothelial cadherin, liver-intestine cadherin and vascular endothelial growth factor in gastric cancer.
Korean J Gastroenterol
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The aims of this study were to examine the expressions of endothelium specific VE-cadherin, intestine specific LI-cadherin, and vascular endothelial growth factor (VEGF), and to determine their relationships with the clinicopathological parameters of gastric cancer.
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FOXO1 impairs whereas statin protects endothelial function in diabetes through reciprocal regulation of Kruppel-like factor 2.
Cardiovasc. Res.
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Krüppel-like factor 2 (KLF2) is implicated as a key molecule maintaining endothelial function. This study was designed to evaluate the reciprocal regulation of KLF2 by the forkhead transcription factor FOXO1, and the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin, in hyperglycaemic conditions.
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Ischemic colitis during interferon-ribavirin therapy for chronic hepatitis C: a case report.
World J. Gastroenterol.
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Ischemic colitis is a rare complication of interferon administration. Only 9 cases in 6 reports have been described to-date. This report describes a case of ischemic colitis during pegylated interferon and ribavirin treatment for chronic hepatitis C, and includes a review of the relevant literature. A 48-year-old woman was treated with pegylated interferon ?-2a and ribavirin for chronic hepatitis C, genotype Ib. After 19 wk of treatment, the patient complained of severe afebrile abdominal pain with hematochezia. Vital signs were stable and serum white blood cell count was within the normal range. Abdominal computed tomography showed diffuse colonic wall thickening from the splenic flexure to the proximal sigmoid colon, which is the most vulnerable area for the development of ischemic colitis. Colonoscopy revealed an acute mucosal hyperemic change, with edema and ulcerations extending from the proximal descending colon to the sigmoid colon. Colonic mucosal biopsy revealed acute exudative colitis. Polymerase chain reaction and culture for Mycobacterium tuberculosis were negative and the cultures for cytomegalovirus, Salmonella and Shigella species were negative. After discontinuation of interferon and ribavirin therapy, abdominal pain and hematochezia subsided and, following colonoscopy showed improvement of the mucosal ulcerations. Ischemic colitis cases during interferon therapy in patients with chronic hepatitis C reported so far have all involved the descending colon. Ischemic colitis is a rarely encountered complication of interferon administration in patients with chronic hepatitis C and should be considered when a patient complains of abdominal pain and hematochezia.
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The Clinical Meaning of Benign Colon Uptake in (18)F-FDG PET: Comparison with Colonoscopic Findings.
Clin Endosc
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Benign colon (18)F-fluorodeoxyglucose (FDG) uptake is frequently observed in asymptomatic individuals. Aims of this study were to investigate the benign colon uptake by whole body FDG-positron emission tomography (PET) in asymptomatic adults and to correlate those results with colonoscopic and histologic findings.
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A 12-week after-school physical activity programme improves endothelial cell function in overweight and obese children: a randomised controlled study.
BMC Pediatr
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Endothelial dysfunction is associated with childhood obesity and is closely linked to the amount and function of endothelial progenitor cells. However, it remains unclear whether endothelial progenitor cells increase with after-school exercise in overweight and obese children. The purpose of this study was to investigate the effects of an after-school exercise programme on endothelial cell function in overweight and obese children.
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Complete genome sequence of Bacillus anthracis H9401, an isolate from a Korean patient with anthrax.
J. Bacteriol.
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Bacillus anthracis H9401 (NCCP 12889) is an isolate from a Korean patient with gastrointestinal anthrax. The whole genome of H9401 was sequenced. It is a circular chromosome containing 5,480 open reading frames (ORFs) and two plasmids, pXO1 containing 202 ORFs and pXO2 containing 110 ORFs. H9401 shows high pathogenicity and genome sequence similarity to Ames Ancestor.
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Secondary sphere formation enhances the functionality of cardiac progenitor cells.
Mol. Ther.
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Loss of cardiomyocytes impairs cardiac function after myocardial infarction (MI). Recent studies suggest that cardiac stem/progenitor cells could repair the damaged heart. However, cardiac progenitor cells are difficult to maintain in terms of purity and multipotency when propagated in two-dimensional culture systems. Here, we investigated a new strategy that enhances potency and enriches progenitor cells. We applied the repeated sphere formation strategy (cardiac explant ? primary cardiosphere (CS) formation ? sphere-derived cells (SDCs) in adherent culture condition ? secondary CS formation by three-dimensional culture). Cells in secondary CS showed higher differentiation potentials than SDCs. When transplanted into the infarcted myocardium, secondary CSs engrafted robustly, improved left ventricular (LV) dysfunction, and reduced infarct sizes more than SDCs did. In addition to the cardiovascular differentiation of transplanted secondary CSs, robust vascular endothelial growth factor (VEGF) synthesis and secretion enhanced neovascularization in the infarcted myocardium. Microarray pathway analysis and blocking experiments using E-selectin knock-out hearts, specific chemicals, and small interfering RNAs (siRNAs) for each pathway revealed that E-selectin was indispensable to sphere initiation and ERK/Sp1/VEGF autoparacrine loop was responsible for sphere maturation. These results provide a simple strategy for enhancing cellular potency for cardiac repair. Furthermore, this strategy may be implemented to other types of stem/progenitor cell-based therapy.
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O-GlcNAc regulates pluripotency and reprogramming by directly acting on core components of the pluripotency network.
Cell Stem Cell
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O-linked-N-acetylglucosamine (O-GlcNAc) has emerged as a critical regulator of diverse cellular processes, but its role in embryonic stem cells (ESCs) and pluripotency has not been investigated. Here we show that O-GlcNAcylation directly regulates core components of the pluripotency network. Blocking O-GlcNAcylation disrupts ESC self-renewal and reprogramming of somatic cells to induced pluripotent stem cells. The core reprogramming factors Oct4 and Sox2 are O-GlcNAcylated in ESCs, but the O-GlcNAc modification is rapidly removed upon differentiation. O-GlcNAc modification of threonine 228 in Oct4 regulates Oct4 transcriptional activity and is important for inducing many pluripotency-related genes, including Klf2, Klf5, Nr5a2, Tbx3, and Tcl1. A T228A point mutation that eliminates this O-GlcNAc modification reduces the capacity of Oct4 to maintain ESC self-renewal and reprogram somatic cells. Overall, our study makes a direct connection between O-GlcNAcylation of key regulatory transcription factors and the activity of the pluripotency network.
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Changes in transepidermal water loss and skin hydration according to expression of aquaporin-3 in psoriasis.
Ann Dermatol
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Aquaporins (AQPs) are a family of water transporting proteins present in many mammalian epithelial and endothelial cell types. Among the AQPs, AQP3 is known to be a water/glycerol transporter expressed in human skin.
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Human intestinal epithelial cell line SK-CO15 is a new model system to study Na(+)/H(+) exchanger 3.
Am. J. Physiol. Gastrointest. Liver Physiol.
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The Caco-2 cell line represents absorptive polarized intestinal epithelial cells that express multiple forms of Na(+)/H(+) exchanger (NHE) in their plasma membranes. Caco-2 cells express the major apical NHE isoform NHE3, but low NHE3 expression together with inefficient transfection often hamper intended studies. In this study, we examined whether SK-CO15 cells could be used to study NHE3 regulation. SK-CO15 cells grown on Transwell inserts developed polarized epithelial cells with microvilli. The transfection efficiency of SK-CO15 cells was markedly higher compared with Caco-2 cells, an advantage in gene transfer and knockout. SK-CO15 cells expressed NHE1, NHE2, and NHE3. NHE3 expression was significantly greater in these cells than Caco-2, and NHE3 comprised more than half of total NHE activity. Apical expression of NHE3 in SK-CO15 cells was confirmed by confocal immunofluorescence and surface biotinylation. NHE regulatory factors NHERF1 and NHERF2, which are important for regulation of NHE3 activity, were expressed in these cells. Stimulatory response of NHE3 in SK-CO15 cells was assessed by dexamethasone and lysophosphatidic acid (LPA). Treatment with dexamethasone for 24-48 h increased NHE3 expression and activity. Similarly to Caco-2 cells, SK-CO15 cells lacked the expression of the LPA receptor LPA(5,) but exogenous expression of LPA(5) resulted in acute stimulation of NHE3. Forskolin acutely inhibited NHE3 activity in SK-CO15 cells, further attesting the validity of these cells. We conclude that SK-CO15 cells with the amenity for transfection and high endogenous NHE3 expression are a new and better cell model for NHE3 regulatory investigation than widely used Caco-2 cells.
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Benefit of complete revascularization in patients with multivessel coronary disease in the drug-eluting stent era.
Circ. J.
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The benefit of complete (CR) vs. incomplete revascularization (IR) with drug-eluting stent (DES), unlike with bypass grafting, is not well established in patients with multivessel coronary artery disease (MVD).
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Immunoproteomically Identified GBAA_0345, Alkyl Hydroperoxide Reductase Subunit C is a Potential Target for Multivalent Anthrax Vaccine.
Proteomics
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Anthrax is caused by the spore-forming bacterium Bacillus anthracis-, which has been used as a weapon for bioterrorism. Although current vaccines are effective, they involve prolonged dose regimens and often cause adverse reactions. High rates of mortality associated with anthrax have made the development of an improved vaccine a top priority. To identify novel vaccine candidates, we applied an immunoproteomics approach. Using sera from convalescent guinea pigs or from human patients with anthrax, we identified 34 immunogenic proteins from the virulent B. anthracis H9401. To evaluate vaccine candidates, six were expressed as recombinant proteins and tested in vivo. Two proteins, rGBAA_0345 (Alkyl hydroperoxide reductase subunit C) and rGBAA_3990 (Malonyl CoA-acyl carrier protein transacylase), have afforded guinea pigs partial protection from a subsequent virulent-spore challenge. Moreover, combined vaccination with rGBAA_0345 and rPA (Protective antigen) exhibited an enhanced ability to protect against anthrax mortality. Finally, we demonstrated that GBAA_0345 localizes to anthrax spores and bacilli. Our results indicate that rGBAA_0345 may be a potential component of a multivalent anthrax vaccine, as it enhances the efficacy of rPA vaccination. This is the first time that sera from patients with anthrax have been used to interrogate the proteome of virulent B. anthracis vegetative cells. This article is protected by copyright. All rights reserved.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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