https://oak.chosun.ac.kr/handle/2020.oak/18791 Fri, 10 Apr 2026 02:32:38 GMT 2026-04-10T02:32:38Z https://oak.chosun.ac.kr/handle/2020.oak/18813 Title: Studies on the Function of Peroxidasins in Innate Immune System in C. elegans Author(s): Jeong Hoon Cho Abstract: Peroxidasin is a unique member of peroxidase family in that it has extracellular matrix (ECM) motif as well as peroxidase activity. Peroxidasins are involved in consolidation the extracellular matrix during development and in innate immune defense. C. elegans has two functional peroxidasins, PXN-1 and PXN-2, and PXN-2 is known to contribute to innate immune system. However, it is not clear of PXN-1 function in innate immune system. Therefore, this study is focused on the function of PXN-1 and the relationship between PXN-1 and PXN-2 in innate defense system in C. elegans. When pxn-1 was knocked down by RNAi, the worm turned to be more resistant to pathogens, Staphylococcus aureus and Pseudomonas aeruginosa and the enhanced resistance was abolished in pxn-1pxn-2 double knock down. By contrast, pxn-2 knock down showed stronger susceptibility to the pathogens. These results suggest that pxn-2 can contribute the pathogen resistance and pxn-1 can suppress the pathogen resistance. To confirm the idea, overexpression experiments were performed. Overexpression of pxn-1 showed more susceptible to pathogens compared to the control and double overexpression of pxn-1pxn-2 overcame the susceptibility of pxn-1 overexpression to the pathogens. On the other hand, pxn-2 overexpression made the worm more resistant to the pathogens and the resistance was maintained in pxn-1pxn-2 double overexpression. The comparison of the susceptibilities to the bacterial pathogens in above mentioned constructs suggests that PXN-1 suppress the function of PXN-2 in defense against bacterial pathogens in Caenorhabditis elegans. Mon, 31 Dec 2018 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18813 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18812 Title: Effect of Histone Deacetylase Inhibitors on Differentiation of Human Bone Marrow-derived Stem Cells Into Neuron-like Cells Author(s): Sujeong Jang; Seokho Park; Hyong-Ho Cho; Ung Yang; Maru Kang; Jong-Seong Park; Sah-Hoon Park; Han-Seong Jeong Abstract: Mesenchymal stem cells (MSCs) are known to differentiate into multiple lineages, making neurogenic differentiation an important target in the clinical field. In the present study, we induced the neurogenic differentiation of cells using histone deacetylase (HDAC) inhibitors and studied their mechanisms for further differentiation in vitro. We treated cells with the HDAC inhibitors, MS-275 and NaB; and found that the cells had neuron-like features such as distinct bipolar or multipolar morphologies with branched processes. The mRNA expressions encoding for NEFL, MAP2, TUJ1, OLIG2, and SYT was significantly increased following HDAC inhibitors treatment compared to without HDAC inhibitors; high protein levels of MAP2 and Tuj1 were detected by immunofluorescence staining. We examined the mechanisms of differentiation and found that the Wnt signaling pathway and downstream mitogen-activate protein kinase were involved in neurogenic differentiation of MSCs. Importantly, Wnt4, Wnt5a/b, and Wnt11 protein levels were highly increased after treatment with NaB; signals were activated through the regulation of Dvl2 and Dvl3. Interestingly, NaB treatment increased the levels of JNK and upregulated JNK phosphorylation. After MS-275 treatment, Wnt protein levels were decreased and GSK-3β was phosphorylated. In this cell, HDAC inhibitors controlled the non-canonical Wnt expression by activating JNK phosphorylation and the canonical Wnt signaling by targeting GSK-3β. Mon, 31 Dec 2018 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18812 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18811 Title: Depletion of PDCD4 Accelerates Stress Granule Assembly Through Sensitization of Stress Response Pathways Author(s): Jeeho Kim; In Youb Chang; Wooje Lee; Takbum Ohn Abstract: Programmed cell death 4 (PDCD4) is a novel tumor suppressor that function in the nucleus and the cytoplasm and appears to be involved in the regulation of transcription and translation. Stress granules (SGs) are cytoplasmic foci at which untranslated mRNAs accumulate when cells exposed to environmental stresses. Since PDCD4 has implicated in translation repression through direct interaction with eukaryotic translation initiation factor 4A (eIF4A), we here investigated if PDCD4 has a functional role in the process of SG assembly under oxidative stresses. Using immunofluorescence microscopy, we found that PDCD4 is localized to SGs under oxidative stresses. Next, we tested if knockdown of PDCD4 has an effect on the assembly of SG using PDCD4-specific siRNA. Interestingly, SG assembly was accelerated and this effect was caused by sensitization of phosphorylation of eIF2 and dephosphorylation of eIF4E binding protein (4E-BP). These results suggest that PDCD4 has an effect on SG dynamics and possibly involved in capdependent translation repression under stress conditions. Mon, 31 Dec 2018 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18811 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/18809 Title: Ophthalmic Application of Hydrogel Polymer Containing Carbon Nanomaterials Author(s): Jae-Wuk Seok; Yong-Pil Geum; Dong-Seok Shin; A-Young Sung Abstract: This experiment is to evaluate the physical properties of the hydrogel lens with the addition of carbon-based nanomaterials, Graphene oxide and Carbon nanotube, and to confirm the improvement of strength. Hyaluronic acid, a hydrophilic substance, was used as an additive by using HEMA (2-hydroxyethyl methacrylate) and ethylene glycol dimethacrylate (EGDMA) as a base monomers. Graphene oxide and two types of Carbon nanotubes(Amide functionalized and Carboxilic acid functionalized) were added 0.1%, 0.3%, 0.5%, respectively, and the physical properties were analyzed by measuring water content, refractive index, breaking strength and SEM image. In the case of the sample added with each carbon nano material, the water content tended to increase for all three materials. The breaking strength tended to increase in Graphene oxide and Carbon nanotube; Carboxilic acid functionalized, but in the case of Carbon nanotube; amide fuctionalized, the breaking strength tended to decrease. However, Carbon nanotube; amide fuctionalized had the highest breaking strength among the three nano materials. Thus, the addition of certain carbon nanomaterials seems to be appropriate for improving the strength of hydrogel lenses. Mon, 31 Dec 2018 15:00:00 GMT https://oak.chosun.ac.kr/handle/2020.oak/18809 2018-12-31T15:00:00Z