11:10-12:00, Rm 103

Cell: differentiation, division and deathC-17-76The role of G0/G1 switch gene 2 in mitotic clonal expansion andterminal differentiation during adipogenesisHyeonjin Choi¹ , ², Hye-Min Lee¹ , ³, Hyo Jung Kim¹ , ², Jae-woo Kim¹ , ² , ³¹Department of Biochemistry and Molecular Biology, Center for Chronic Metabolic DiseaseResearch, Yonsei University College of Medicine, ²Brain Korea 21 Project for Medical Science,³Department of Integrated OMICS for Biomedical Sciences, Graduate School, Yonsei University,Seoul, KoreaDifferentiation of preadipocytes to adipocytes requires coordinated actions of a largerepertoire of transcription factors. This process occurs in several stages and involves acascade of transcription factors, among which PPARγand CCAAT/enhancer-bindingproteins (C/EBPs) are considered the crucial determinants of adipocyte fate. One of theearliest events occurring in adipogenesis is mitotic clonal expansion (MCE) which isrequired for differentiation of 3T3-L1 cells. Upon hormonal induction, growth-arrestedpreadipocytes synchronously re-enter the cell cycle and undergo several rounds of celldivision. In this study, we carried out microarray analysis and analyzed genes whichmight play an important role during this process. Among them, we sorted out candidates,G0/G1 switch gene 2 (G0S2) which is highly expressed in adipose tissue anddifferentiated adipocytes. We found that the expression of G0S2 was dramaticallyincreased during an early stage of differentiation. Suppression of G0S2 expression withRNA interference significantly inhibited adipogenesis and preadipocyte proliferation andreduced the expression of C/EBPαbut had no effect to C/EBPβ. These studies establishG0S2 as key components controlling an early stage of differentiation in adipogenesis.C-17-79Piperine, a component of black pepper, inhibits adipogenesis byantagonizing PPARγactivity in 3T3-L1 cellsMi-Ran Sung, Ui-Hyun Park, Hye-Sook Youn, Soo-Jong UmDepartment of Bioscience and Biotechnology, BK21 Graduate Program, Sejong University, Seoul143-747, KoreaBlack pepper (Piper nigrum Linne) has been world-widely used as spice and herbalmedicine because of its anti-oxidant, anti-inflammation, and anti-tumor activities. In thisstudy, we investigated the anti-adipogenic activity of black pepper extract and itsconstituent piperine in 3T3-L1 preadipocytes. Both black pepper extract and piperine,without affecting cytotoxicity, strongly inhibited the adipocyte differentiation of 3T3-L1cells as evidenced by Oil Red O staining and levels of accumulated triglyceride. ThemRNA expression of the master adipogenic transcription factors, PPARγ,SREBP-1c,andC/EBPβ, was markedly decreased, especially upon treating piperine. Intriguingly, mRNAlevels of PPARγtarget genes such as adipsin,aP2,and LPL were also down-regulated.Moreover, co-transfection assays indicated that pipierine significantly represses therosiglitazone-induced PPARγtranscriptional activity. GST-pull down assaysdemonstrated that piperine disrupts the rosiglitazone-dependent interaction betweenPPARγand coactivator CBP. Overall, these results suggest that piperine, a majorcomponent of black pepper, attenuates fat cell differentiation by down-regulating PPARγactivity as well as suppressing PPARγexpression, thus leading to potential treatment forobesity-related diseases.C-17-77Direct conversion of human adipocytes into bone-forming cells bycooperative transduction of transcription factorsKeun-Ho Kim, Ji-Hyun Jung and Je-Yoel ChoDepartment of biochemistry, school of dentistry, Kyungpook National University, RM 211,101Dong-In dong 2ga, Daegu 700-422, KoreaAdipocyte acquired by liposuction can be used in cell therapy. In this preliminary study,we performed the conversion of human pre-adipocyte cell (SGBS strain) into osteoblasticcells. Bone formation is regulated by many factors, especially transcription factors, whichare protein that bind to specific DNA sequences, thereby controlling the transcription ofgenetic information from DNA to mRNA. We used four bone related transcription factors -Runx2, Osterix, ATF4 and LEF1. These factors have a close relation during boneformation and osteoblast differentiation. We used lentiviral vectors that are effectivevehicles for transducing and stably expressing DNA fragments in almost any mammaliancell, including non-dividing cells. To determine whether cooperative transduction of thesetranscription factors enhance Osteogenic transdifferentiation, we produced lentiviruscontaining genes for each transcription factors and infected into adipocytes. Weconfirmed each transgene expression using RT-PCR and western blotting. In furtherstudy, we will confirm the reprogramming of adipocytes through bone-related markergene expression such as alkaline phosphatase, osteopontin, osteocalcin and type Icollagen and confirm bone formation capacity of reprogrammed cells in vivo using nudemice.C-17-80Characterization of Gender-Specific Bovine SerumJihoe Kim¹, Minsoo Kim², Sang-Soep Nahm², Dong-Mok Lee¹, Smritee Pokharel¹,Inho Choi¹ , *¹School of Biotechnology, Yeungnam University, Gyeongsan, Korea. ²College of VeterinaryMedicine, Konkuk University, 1 Hwayangdong, Gwangjingu, Seoul 143-701, KoreaAdult bovine serum contains a variety of nutrients including inorganic minerals, vitamins,salts, proteins, lipids as well as growth factors that promote animal cell growth. Toevaluate the potential use of gender-specific bovine serum(GSBS) for cell culture,biochemical properties of male serum(MS), female serum(FS) and castrated-maleserum(CMS) were investigated. Chemical profile of GSBS was similar to that of bovinereferences except for glucose, cholecystokinin, lactate dehydrogenase and potassium.FS showed elevated total protein and sodium concentrations compared to MS and CMS.Proteins present in MS, FS and CMS but absent in fetal bovine serum(FBS) wereselected by 2D gel electrophoresis and identified by peptide mass fingerprinting. Some ofthe identified proteins are known to be involved in immune responses and the others withunknown physiological roles. It was found that some proteins such as α-2 macroglobulinappeared to be gender-specific with higher contents in FS. Insulin and testosterone wassignificantly higher in MS, 17-estradiol and estrone were higher in FS, as compared tothe other sera. The results indicate that each GSBS has a different ratio of components.Differences in serum may affect cell cultures in a different manner and could bebeneficial.C-17-78Secreted protein acidic and rich in cysteine regulates TGF-β1-induceddifferentiation of human mesenchymal stem cells to smooth muscle cellsEun Kyoung Do, Young Mi Kim and Jae Ho KimMedical Research Center for Ischemic Tissue Regeneration & Medical Research Institute, School ofMedicine, Pusan National University, Yangsan 626-770, KoreaHuman mesenchymal stem cells (MSCs) have a self-renewal capacity and differentiationpotential toward diverse cell types. Transforming growth factor-β1 (TGF-β1) inducesdifferentiation of mesenchymal stem cells to smooth muscle cells. Matricellular proteinSPARC (Secreted protein acidic and rich in cysteine) has been implicated in cellulardifferentiation and tissue response to injury. However, the role of SPARC in differentiationof human mesenchymal stem cells has not yet known. We identified SPARC as a TGF-β1-induced protein in human adipose tissue-derived mesenchymal stem cells (hASC).TGF-β1 treatment stimulated the mRNA and the protein levels of SPARC in hASCs.Pretreatment of hASC with SB431542, a TGF-β1 receptor inhibitor, blocked the TGF-β1-induced SPARC expression. Depletion of endogenous SPARC using lentiviral smallhairpin RNA or small interfering RNA abrogated the TGF-β1-induced expression of α-SMA, a marker of smooth muscle cells, in hASCs. These results suggest a pivotal role ofSPARC in the TGF-β1-induced differentiation of hASCs to smooth muscle cells.C-17-81Hypoxia maintains high expression of anti-adipogenic factor,preadipocyte factor-1 (Pref-1)Yun-Won Moon, Young-Kwon Park and Hyunsung ParkDepartment of Life Science, University of Seoul, Seoul 130-743, KoreaAdipogenesis requires expression of CCAAT enhancer binding protein (C/EBP) βandC/EBPδwhich are key activators of adipocyte differentiation and reduction of antiadipgenicfactor, named Preadipocyte Factor 1 (Pref-1). Secreted Pref-1 is released bytumor necrosis factor alpha converting enzyme (TACE) inhibits adipogenic differentiationby up-regulating SRY (sex determining region Y) - box 9 (Sox9) which suppressesC/EBPs expression. Here, we showed that hypoxic environment maintains both mRNAand protein of Pref-1 in mouse 3T3-L1 preadipocytes and human adipocyte derivedmesenchymal stem cells even in the presence of adipogenic hormones. Furthermore,hypoxic treatment resumes the expression of Pref-1, thus blocks the expression ofadipogenic transcription factor, PPARγ. By using HIF-1α-knockdown 3T3-L1 cells, wetested whether Hypoxia inducible factor-1α(HIF-1α) is essential for hypoxic induction ofPref-1. ChIP analyses on the promoter region of Pref-1 showed the level of trimethylationof Lys 4 on histone 3(H3K4me3) is maintained high under hypoxia, whereas the level oftrimethylation of Lys 27 on histone 3(H3K27me3) is low by hypoxia. [This work wassupported by NRF grant No. 2007-0054581]212 Korean Society for Biochemistry and Molecular Biology