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The Expression of DDX3 by Receptor in Neuronal Cells
Youngseo PARK,Junho LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
DDX3 is a host viral factor that can inhibit the hepatitis B virus induced innate immune responses. In this study, the 20 bioactive compounds were screened the effects on DDX3 and we found that 5-HT upregulated DDX3 promoter activity via the 5-HT7 receptor on liver hepatocellular cells (HepG2 cells) by using a luciferase assay, RT-PCR analysis, and western blot analysis. Furthermore, we are trying to elucidate the pathways involved in the stimulating effect of 5-HT on DDX3 expression to induce innate immune responses against hepatitis B virus infection. A knockdown of the 5-HT7 receptor by transfection si-5-HT7 receptors or si-control into HepG2 cells treated by 5-HT (or 5-HT plus agonist) confirmed the role of the 5-HT7 receptor in DDX3 expression. The IFN-β-Luc expression and level of hepatitis B virus surface Antigen (HBsAg) showed that DDX3 mediated by the 5-HT7 agonist (AS-19) increased IFN-β expression and inhibited HBV replication. Luciferase assays showed the involvement of 5-HT7 receptors in DDX3 expression via cAMP/AC/PKA pathways by using protein kinas A (PKA) and adenylyl cyclase inhibitor (MDL 12330A). AS-19 mediated DDX3 promoter activated PKA extracellular signal regulated kinase ERK signaling the p53 phosphorylation (-1080/-1070) resulted in upregulation of DDX3 promoter transactivation via the 5-HT7 receptors agonist. Overall, 5-HT7 was found to be a new potential target to inhibit hepatitis B infection by activating AC/PKA/ERK pathways by phosphorylating p53 via the 5-HT7 agonist response by mediating DDX3 expression.
Hybrid Metal-Halide Perovskite-MoS<sub>2</sub> Phototransistor
Park, Youngseo,Lee, Sanghyun,Park, Hui Joon,Baac, Hyoung Won,Yoo, Geonwook,Heo, Junseok American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11
<P>Two-dimensional (2D) molybdenum disulfide (MoS2) has attracted much attention as a promising next-generation optoelectronic device. In particular, multilayer MoS2 has superior optical properties compared to mono-or few-layer MoS2 because of its higher density of states and wider spectral response. However, as the number of layers increases, multilayer MoS2 becomes indirect, resulting in poor light absorption and low photoresponsivity. Here, we report the enhanced photocurrent response of a multilayer MoS2 thin-film transistor by stacking an organometal halide perovskite (CH3NH3PbI3) layer on top of the multilyaer MoS2. With the perovskite overlayer, the photocurrent increased by two orders of magnitude, and thus our proposed hybrid phototransistor exhibited significantly enhanced photoresponsivity of similar to 1.1 A/W as well as detectivity of similar to 9 x 10(10) Jones compared to the MoS2 phototransistor without the perovskite layer. We also observe that the electrical properties change because of the effect of the overlayer. Our result indicates that multilayer MoS2 with a CH3NH3PbI3 overlayer can be a promising structure for high-performance MoS2-based photodetector applications.</P>
Study for the inhibition of transient receptor potential vanilloid type 1 by gomisin A
Youngseo Park,Junho Lee 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7
Transient receptor potential (TRP) channels play an essential role as environmental sensors in primary afferent neurons. The transient receptor potential vanilloid type 1 (TRPV1) channel, also known as the capsaicin receptor, is critical to chemical and physical sensation, and is regulated by anesthetic chemicals through an unknown mechanism. In the present study, we investigated the effect of gomisin A on human TRPV1 channel activity. Schisandra chinensis contains bio-active compounds such as the gomisin derivatives and their related compounds. Co-application with gomisin A inhibited the capsaicin-mediated inward peak current. This inhibitory effect of gomisin A on capsaicin-induced inward current showed concentration-dependence, and was reversible. The half maximal inhibitory concentration of gomisin A was 62.7 ± 8.4 μM. In addition, this inhibition occurred in a non-competitive and voltage-insensitive manner. Furthermore, molecular docking studies of gomisin A on TRPV1 showed it interacted predominantly with residues at cavities in the segment 1 and 2 of each subunit. Four potential binding sites for this ligand in the extracellular region at sensor domain of TRPV1 channel were identified. Point mutagenesis studies were undertaken, and gomisin A potency decreased for both the Y453A and N467A mutants. The double mutation of Y453 and N467 was significantly attenuated inhibitory effects by gomisin A. In summary, this study revealed the molecular basis for the interaction between TRPV1 and gomisin A, and provides a novel potent interaction ligand.
Park, Chang Geun,Park, Su Hong,Kim, Youngseo,Nguyen, Thanh Luan,Woo, Han Young,Kang, Hungu,Yoon, Hyo Jae,Park, Sungnam,Cho, Min Ju,Choi, Dong Hoon The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.37
<P>Conjugated block copolymers containing donor (D) and acceptor (A) blocks have high potential for single component polymer solar cells (SC-PSCs), but still exhibit the complexity of polymer synthesis and low device efficiency. In this research, we successfully synthesized a new fully conjugated D-A block copolymer (CDABP) by performing the entire reaction in one-pot from start to completion. This polymerization method has the advantage of saving synthesis time and cost. The photoluminescence (PL) of the CDABP film was completely quenched due to photoinduced inter/intramolecular charge transfer. A single component polymer solar cell (SC-PSC) with a CDABP film annealed at 180 °C showed the maximum power conversion efficiency (PCE) of 5.28%, a high short circuit current of 10.77 mA cm<SUP>−2</SUP> and a fill factor of 62.86%, which is much higher than that (2.62%) of the device with the as-cast film. This performance can be attributed to its fine internal/surface morphology and high crystallinity of the CDABP film. In addition, transient absorption experiments on the CDABP films showed that charge carrier generation is faster and the lifetime of the generated charge carriers is longer in the annealed film than in the as-cast film. Our research explicitly provides a new structural design and simple synthesis strategy for D-A conjugate block copolymers for high-efficiency SC-PSCs.</P>
Bias-dependent photoresponsivity of multi-layer MoS <sub>2</sub> phototransistors
Park, Jinwu,Park, Youngseo,Yoo, Geonwook,Heo, Junseok Springer US 2017 NANOSCALE RESEARCH LETTERS Vol.12 No.1
<P>We studied the variation of photoresponsivity in multi-layer MoS<SUB>2</SUB> phototransistors as the applied bias changes. The photoresponse gain is attained when the photogenerated holes trapped in the MoS<SUB>2</SUB> attract electrons from the source. Thus, the photoresponsivity can be controlled by the gate or drain bias. When the gate bias is below the threshold voltage, a small amount of electrons are diffused into the channel, due to large barrier between MoS<SUB>2</SUB> and source electrode. In this regime, as the gate or drain bias increases, the barrier between the MoS<SUB>2</SUB> channel and the source becomes lower and the number of electrons injected into the channel exponentially increases, resulting in an exponential increase in photoresponsivity. On the other hand, if the gate bias is above the threshold voltage, the photoresponsivity is affected by the carrier velocity rather than the barrier height because the drain current is limited by the carrier drift velocity. Hence, with an increase in drain bias, the carrier velocity increases linearly and becomes saturated due to carrier velocity saturation, and therefore, the photoresponsivity also increases linearly and becomes saturated.</P>