11:10-12:00, Rm 103

Cell: differentiation, division and deathC-17-14Regulation of follicle growth and apoptosis in cultured mouse ovariesby NGF and oxygenWoojin Pi and Jaesook RohDepartment of Anatomy & Cell Biology, Hanyang Medical University, #17, Haengdang-Dong,Sungdong-Ku, Seoul, 133-792 KoreaCryopreservation of ovarian tissue has been proposed for use in preserving femalefertility before anticancer chemo-radiotherapy, because ovarian tissue contains a largepool of non-growing, primordial follicles. The mechanisms that regulate the exit of folliclesfrom the pool are poorly understood. To determine optimal conditions for in vitro ovarianculture, we investigated the effects of NGF and oxygen concentration on follicle growthand apoptosis. Oxygen concentration affected both cell proliferation and apoptosis. Under20% oxygen, but not 1.5% or 5%, NGF decreased apoptosis in mouse ovaries by downregulatingthe pro-apoptotic genes Bax and p53. In conclusion, high oxygen tensionduring in vitro ovarian culture promotes follicle growth and, in conjunction with NGF,suppresses apoptosis. The efficiency of this method to preserve fertility depends in parton the level of atresia. These results suggest that oxygen and NGF may be used toincrease numbers of preantral follicles and mature oocytes in the culture of humanovarian cortical strips. [This work was supported by National Research Foundation ofKorea Grant funded by the Korean Government (KRF-2009-0065769)].C-17-17Luteolin inhibits H₂O₂-induced cellular senescence via modulation ofSIRT1 and p53Rizhe Zhu, Shang Shang Gao, Bok-Ryang Kim and Byung-Min ChoiDepartment of Biochemistry, School of Medicine, Wonkwang University, Iksan, Chonbuk 570-749,KoreaLuteolin have been associated to the prevention of cancer, diabetes, as well ascardiovascular and neurodegenerative diseases. However, demonstration regarding therole of luteolin in anti-aging process is still deficient. In this study, we selected the H₂O₂inducedcellular senescence model in HEI-OC1 cells to investigate the protection ofluteolin against oxidative stress-induced cellular senescence and associated molecularmechanisms. We found that luteolin considerably reversed senescence-like phenotypesin the oxidant challenged model, including alterations of morphology, cell proliferation,senescence-associated (SA) β-galactosidase staining, DNA damage, as well as relatedmolecules expression such as p53 and p21. Luteolin was found to induce the expressionof Sirtuin1 (SIRT1) in dose- and time-dependent manners. Moreover, the protective effectof luteolin on H₂O₂-induced cellular senescence was abrogated through inhibition ofSIRT 1. Also, SIRT1 siRNA efficiently abolishes H₂O₂-induced p53 phosphorylation andDNA damage. Our results demonstrated that luteolin inhibits oxidative stress-inducedcellular senescence, which might be mediated by modulation of p53 and SIRT1.C-17-15Involvement of modified cyclophilin A in ER-Stress induced apoptosisof human liver cellHun Sung Kim, Kwon Jeong and Wonchae ChoeDepartment of Biochemistry & Molecular Biology, Medical Research Center for ROS, Post -BrainKorea21, School of medicine, Kyung Hee University, Seoul 130-701, KoreaThe protein is guided to the ER by a signal sequence is converted to an intermediateform. Cyclophilin A (CypA) is an intracellular protein that has peptidyl-prolyl cis-transisomerase (PPIase) enzymatic activity. our study showed that the localization of CypA isregulated by prolactin signal sequence. The lumen of the ER is a unique environment,containing the highest concentration of Ca2+ within the cell because of active transport ofcalcium ions by Ca2+ ATPases. The lumen is an oxidative environment, critical forformation of disulfide bonds and proper folding of proteins destined for secretion ordisplay on the cell surface. The adaptive responses to misfolded proteins in the ERprovide protection from cell death. During ER stress, Ask1 is recruited to oligomerizedIre1 complexes containing TRAF2, activating this kinase and causing downstreamactivation of JNK and p38 MAPK. The kinase pathway initiated by Ask1 leads to JNKactivation, and JNK-mediated phosphorylation activates the proapoptotic protein Bim ,while inhibiting the anti-apoptotic protein Bcl-2. We identified ER existence of a modifiedcyclophilin A expressed in the Endoplasmic reticulum directed by the prolactin signalsequence that resisted ER-stress-indeced cell death in human liver cells.C-17-18Trancriptional regulation and functions of Cyclophilin A in muscledifferentiationNguyen Minh Nam, Tae Gyu Choi and Sung Soo KimDepartment of Biochemistry and Molecular Biology, Medical Research Center for Bioreaction toReactive Oxygen Species and Biomedical Science Institute, School of Medicine, Kyung HeeUniversity, Seoul 130-701, KoreaCyplophilin A (CypA) encodes a member of the peptidyl-prolyl cis-trans isomerase(PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptidebonds in oligopeptides and accelerate the folding of proteins. The encoded protein is acyclosporin binding-protein and may play a role in cyclosporin A-mediatedimmunosuppression. On the one hand, myogenesis is referred to the generationprocesses of muscle fibers from the fusion of myoblasts (muscle stem cells) into multinucleatedfibers (called myotubes), as muscle specific genes such as MEF2, Myf5 andMHC regulated. In the process of the myogenesis, we CypA expression is markedlyincreased in time and day dependent manner. We next investigated that in the promoterregion transcription factor upregulates CypA and found significant DNA binding sites ofNFκB (about -1000bp). In result, NFκB is demponstrated as the specific transcriptionfactor of CypA through promoter assays and semi conserved gene amplification. Inaddition, the muscle fiber was not formed in cells of CypA knockdown. In conclusion,CypA is a pivotal molecular compound in muscle differentiation.C-17-16Nicotinamide phosphoribosyltransferase in chondrocytededifferentiationEun-Hee Hong and Sang-Gu HwangDivision of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul139-706, KoreaNicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme inregenerating nicotinamide adenine dinucleotide (NAD) from nicotinamide in mammals.NAMPT has crucial roles for many cellular functions by regulating NAD-dependent SIRT1deacetylase. Although much is known about NAMPT as key molecule of cytokineresponse, the roles of NAMPT in dedifferentiation of chondrocytes are not well defined. Inthis study, we found that IL-1βor LPS induced NAMPT expression, in turn, activatedSIRT1 protein without any alteration of the expression level. SIRT1 activation promotedinduction of ERK and p38 kinase activities in response to IL-1β. Inhibition of NAMPT orSIRT1 significantly suppressed chondrocyte dedifferentiation. Therefore, we demonstratethat association of NAMPT-SIRT1 signaling with MAP Kinase for cytokine-mediatedchondrocyte dedifferentiation. Our findings may have implications for exploring theNAMPT pathway in the prevention and treatment of chondrocyte diseases. [This workwas supported by the Nuclear Research & Development Program of the Korea ResearchFoundation Grant].C-17-19Antimycin A sensitizes TRAIL-induced apoptosis through downregulationof c-FLIP and Bcl-2 proteinsSung-Jun Lee, Eon-Gi Sung, In-Hwan Song, Joo-Young Kim, Tae-Jin LeeDepartment of Anatomy, College of Medicine, Yeungnam University, 317-1 Daemyung-DongNam-Gu, Daegu 705-717, KoreaTumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been paid attentionas a potential anti-cancer drug, because it induces apoptosis in a wide variety of cancercells but not in most normal human cell types. Here, we showed that co-treatment withsubtoxic doses of antimycin A (AMA), an inhibitor of electron transport and TRAILinduced apoptosis in human renal cancer cells, Caki cells, but not in normal tubularkidney cells. Treatment of Caki cells with AMA down-regulated c-FLIP and Bcl-2 proteinsin dose- and time-dependent manners. AMA-induced decreases in c-FLIPL and c-FLIPsprotein levels were involved in the increased protein instability, which was confirmed bythe result that treatment with protein biosynthesis inhibitor, CHX, reduced c-FLIPL and c-FLIPs proteins level by AMA. We also found that AMA induced down-regulation of Bcl-2at the transcriptional level. Pretreatment with N-acetyl-l-cysteine (NAC) slightly inhibitedthe expression levels of DR5 up-regulated by the treatment of AMA, suggesting that AMAappears to be partially dependent on the generation of ROS for up-regulation of DR5.Taken together, the present study demonstrates that AMA enhances TRAIL-inducedapoptosis in human renal cancer cells by DR5 up-regulations, as well as cFLIP and Bcl-2down-regulations.202 Korean Society for Biochemistry and Molecular Biology