Direct Gingival Fibroblast/Osteoblast Transdifferentiation via Epigenetics

Cho, Y.,Kim, B.,Bae, H.,Kim, W.,Baek, J.,Woo, K.,Lee, G.,Seol, Y.,Lee, Y.,Ku, Y. Journal of Dental Research, Inc 2017 Journal of dental research Vol.96 No.5

<P>Alveolar bone resorption caused by trauma or periodontal diseases has represented a challenge for both dental clinicians and researchers. In this study, we evaluate the osteogenic potential of human gingival fibroblasts (HGFs) through a direct transdifferentiation from HGFs to functional osteoblasts via epigenetic modification and osteogenic signaling with bone morphogenetic protein 2 (BMP2) in vitro and in vivo. HGF treatment with 5-aza-2'-deoxycytidine (5-aza-dC) induced demethylation in the hypermethylated CpG islands of the osteogenic lineage marker genes RUNX2 and ALP, and subsequent BMP2 treatment successfully drove the fibroblasts to the osteoblasts' lineage. Cell morphological changes viewed under microscopy and alkaline phosphatase (ALP) and alizarin red S (ARS) staining confirmed the osteoblastic change mediated by epigenetic modification as did real-time polymerase chain reaction (PCR), methylation-specific PCR (MSP), and chromatin immunoprecipitation (ChIP) assay, which demonstrated the altered methylation patterns in the RUNX2 and ALP promoter regions and their effect on gene expression. Furthermore, micro-computed tomography (CT) analysis of in vivo mouse cell transplantation experiments showed high-density signal in the epigenetically modified HGF group; in addition, a significant amount of bone formation was observed in the transplanted material using hematoxylin and eosin (H&E) staining as well. Collectively, our results indicate that epigenetic modification permits the direct programming of HGFs into functional osteoblasts, suggesting that this approach might open a novel therapeutic avenue in alveolar bone regeneration.</P>

Hexanal-induced changes in miRNA-mRNA interactions in A549 human alveolar epithelial cells

Cho, Y.,Lim, J. h.,Jeong, S. C.,Song, M. K.,Ryu, J. C. Springer Science + Business Media 2015 Toxicology and Environmental Health Sciences Vol.7 No.2

Energy concentration of the focusing energy-critical fNLS

Cho, Y.,Hwang, G.,Shim, Y.S. Academic Press 2016 Journal of mathematical analysis and applications Vol.437 No.1

<P>We consider the fractional nonlinear Schrodinger equation (fNLS) with non-local dispersion vertical bar del vertical bar(alpha) and focusing energy-critical Hartree type nonlinearity [-(vertical bar x vertical bar(-2 alpha) * vertical bar u vertical bar(2))u]. We consider the energy -concentration phenomena of radial blowup solutions near the maximal existence time. We use the concentration -compactness approach of [19] for confined case and kinetic energy trapping approach of [21] for unconfined case. (C) 2015 Elsevier Inc. All rights reserved.</P>

A Study of Predicting Method of Residual Stress Using Artificial Neural Network in $CO_2$Arc welding

Cho, Y.,Rhee, S.,Kim, J.H. The Korean Welding and Joining Society 2001 International journal of Korean welding society Vol.1 No.2

A prediction method for determining the welding residual stress by artificial neural network is proposed. A three-dimensional transient thermo-mechanical analysis has been performed for the $CO_2$ arc welding using the finite element method. The first part of numerical analysis performs a three-dimensional transient heat transfer analysis, and the second part then uses the results of the first part and performs a three-dimensional transient thermo-elastic-plastic analysis to compute transient and residual stresses in the weld. Data from the finite element method are used to train a back propagation neural network to predict the residual stress. Architecturally, the fully interconnected network consists of an input layer for the voltage and current, a hidden layer to accommodate the failure mechanism mapping, and an output layer for the residual stress. The trained network is then applied to the prediction of residual stress in the four specimens. It is concluded that the accuracy of the neural network predicting method is fully comparable with the accuracy achieved by the traditional predicting method.

Rapid adaptation using linear spectral transformation for embedded speech recognisers

Cho, Y.,Yook, D. IET 2008 Electronics letters Vol.44 No.17

<P>Embedded speech recognisers are typically used in unknown mobile environments where the acoustic conditions frequently change. Since a large amount of adaptation data is not usually available for such environments, the adaptation methods for the acoustic models of these recognisers must improve the recognition performance with only a small amount of adaptation data. In this Letter, we show that maximum likelihood linear spectral transformation provides the advantage of rapid adaptation using a very limited amount of adaptation data for the embedded acoustic models.</P>

Adipokine Resistin Is a Key Player to Modulate Monocytes, Endothelial Cells, and Smooth Muscle Cells, Leading to Progression of Atherosclerosis in Rabbit Carotid Artery

Cho, Y.,Lee, S.E.,Lee, H.C.,Hur, J.,Lee, S.,Youn, S.W.,Lee, J.,Lee, H.J.,Lee, T.K.,Park, J.,Hwang, S.J.,Kwon, Y.W.,Cho, H.J.,Oh, B.H.,Park, Y.B.,Kim, H.S. Elsevier Biomedical 2011 JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY - Vol.57 No.1

Objectives: We investigated the effects of human resistin on atherosclerotic progression and clarified its underlying mechanisms. Background: Resistin is an adipokine first identified as a mediator of insulin resistance in murine obesity models. But, its role in human pathology is under debate. Although a few recent studies suggested the relationship between resistin and atherosclerosis in humans, the causal relationship and underlying mechanism have not been clarified. Methods: We cloned rabbit resistin, which showed 78% identity to human resistin at the complementary deoxyribonucleic acid level, and its expression was examined in 3 different atherosclerotic rabbit models. To evaluate direct role of resistin on atherosclerosis, collared rabbit carotid arteries were used. Histological and cell biologic analyses were performed. Results: Rabbit resistin was expressed by macrophages of the plaque in the 3 different atherosclerotic models. Peri-adventitial resistin gene transfer induced macrophage infiltration and expression of various inflammatory cytokines, resulting in the acceleration of plaque growth and destabilization. In vitro experiments elucidated that resistin increased monocyte-endothelial cell adhesion by upregulating very late antigen-4 on monocytes and their counterpart vascular cell adhesion molecule-1 on endothelial cells. Resistin augmented monocyte infiltration in collagen by direct chemoattractive effect as well as by enhancing migration toward monocyte chemotactic protein-1. Administration of connecting segment-1 peptide, which blocks very late antigen-4 x vascular cell adhesion molecule-1 interaction, ameliorated neointimal growth induced by resistin in vivo. Conclusions: Our results indicate that resistin aggravates atherosclerosis by stimulating monocytes, endothelial cells, and vascular smooth muscle cells to induce vascular inflammation. These findings provide the first insight on the causal relationship between resistin and atherosclerosis.

A Sobolev estimate for the adjoint restriction operator

Cho, Y.,Guo, Z.,Lee, S. Springer Science + Business Media 2015 Mathematische Annalen Vol.362 No.3

Facile synthesis of flower-like α-Co(OH)₂ nanostructures for electrochemical water splitting and pseudocapacitor applications

Cho, Y.,Lee, J.,Nguyen, T.T.H.,Bae, J.W.,Yu, T.,Lim, B. Korean Society of Industrial and Engineering Chemi 2016 Journal of industrial and engineering chemistry Vol.37 No.-

<P>We describe a facile synthetic route to alpha-Co(OH)(2) nanostructures by heating a solution containing CoCl2, ethylene glycol, and oleylamine. Electron microscopy and X-ray diffraction analyses revealed that flower-like nanostructures of a-Co(OH)2 were formed by assembly of thin alpha-Co(OH)(2) nanosheets. These nanostructures exhibited high activity for electrochemical water splitting with a current density comparable to that obtained on the commercial Pt wire electrode. In addition, these flower-like alpha-Co(OH)(2) nanostructures showed specific capacitance as high as 440 F/g at a current density of 1 A/g and excellent stability without any noticeable loss in capacitance after 5000 cycles of the galvanostatic charge-discharge test. (C) 2016 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry.</P>

Enhanced energy harvesting based on surface morphology engineering of P(VDF-TrFE) film

Cho, Y.,Park, J.B.,Kim, B.S.,Lee, J.,Hong, W.K.,Park, I.K.,Jang, J.E.,Sohn, J.I.,Cha, S.,Kim, J.M. Elsevier 2015 Nano energy Vol.16 No.-

Polyvinylidene fluoride (PVDF) has great potential for its use as an energy harvesting material as it exhibits not only outstanding piezoelectric and electrostatic characteristics resulting from ferroelectric effects, but also remarkably robust stability against repeated mechanical stress compared to inorganic materials. We report enhanced performances of poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) based energy generators with wider range of selections of flexible substrates through a surface morphology engineering using solvent annealing method as the key technology for simple and cost-effective fabrication at room temperature. It is clearly revealed that a solvent annealed P(VDF-TrFE) film is crystallised at room temperature and that the surface morphology is changed from a rough surface into a smooth and flat surface with increasing annealing time. This surface morphology engineering results in 8 times enhanced output voltage and current of the energy generators because of well-aligned electrical dipoles. We also demonstrate a highly transparent and flexible energy generator by employing graphene electrodes with the solvent annealed P(VDF-TrFE) film, which can be effectively harvesting various mechanical energy sources.

Activating Injury-Responsive Genes with Hypoxia Enhances Axon Regeneration through Neuronal HIF-1α

Cho, Y.,Shin, J.,Ewan, E.,Oh, Y.,Pita-Thomas, W.,Cavalli, V. Cell Press 2015 Neuron Vol.88 No.4

Injured peripheral neurons successfully activate a proregenerative transcriptional program to enable axon regeneration and functional recovery. How transcriptional regulators coordinate the expression of such program remains unclear. Here we show that hypoxia-inducible factor 1α (HIF-1α) controls multiple injury-induced genes in sensory neurons and contribute to the preconditioning lesion effect. Knockdown of HIF-1α in vitro or conditional knock out in vivo impairs sensory axon regeneration. The HIF-1α target gene Vascular Endothelial Growth Factor A (VEGFA) is expressed in injured neurons and contributes to stimulate axon regeneration. Induction of HIF-1α using hypoxia enhances axon regeneration in vitro and in vivo in sensory neurons. Hypoxia also stimulates motor neuron regeneration and accelerates neuromuscular junction re-innervation. This study demonstrates that HIF-1α represents a critical transcriptional regulator in regenerating neurons and suggests hypoxia as a tool to stimulate axon regeneration.