Background: Porcine pluripotent stem cells (pPSCs) would provide enormous potential for agriculture and biomedicine. However, authentic pPSCs have not established yet because standards for pPSCs-specific markers and culture conditions are not clear. Therefore, the present study reports comparative pluripotency characteristics in porcine induced pluripotent stem cells (piPSCs) derived from different viral transduction and reprogramming factors [Lenti-iPSCs (OSKM), Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM)]. Methods: Porcine fibroblasts were induced into Lenti-iPSCs (OSKM) and Lenti-iPSCs (OSKMNL) by using Lentiviral vector and Sev-iPSCs (OSKM) by using Sendaiviral vector. Expressions of endogenous or exogenous pluripotency-associated genes, surface marker and in vitro differentiation in between Lenti-piPSCs (OSKM), Lenti-iPSCs (OSKMNL) and Sev-piPSCs (OSKM) were compared. Results: Colonial morphology of Lenti-iPSCs (OSKMNL) closely resembles the naïve mouse embryonic stem cells colony for culture, whereas Sev-iPSCs (OSKM) colony is similar to the primed hESCs. Also, the activity of AP shows a distinct different in piPSCs (AP-positive (+) Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM), but AP-negative (-) LentiiPSCs (OSKM)). mRNAs expression of several marker genes (OCT-3/4, NANOG and SOX2) for pluripotency was increased in Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM), but Sev-iPSCs (OSKM). Interestingly, SSEA-1 of surface markers was expressed only in Sev-iPSCs (OSKM), whereas SSEA-4, Tra-1-60 and Tra-1-81 were positively expressed in Lenti-iPSCs (OSKMNL). Exogenous reprogramming factors continuously expressed in Lenti-iPSCs (OSKMNL) for passage 20, whereas Sev-iPSCs (OSKM) did not express any exogenous transcription factors. Finally, only Lenti-iPSCs (OSKMNL) express the three germ layers and primordial germ cells markers in aggregated EBs. Conclusions: These results indicate that the viral transduction system of reprograming factors into porcine differentiated cells display different pluripotency characteristics in piPSCs.

Since embryonic stem cells (ESCs) were first established from explant cultures of in vivo day 3.5 mouse embryos, the establishment of ESCs from species such as primates and rat has been developed. However, this success relies on the development of culture medium suitable for human and rat cells, which has different requirements from the murine ESC. In general, the establishment of ESC from pig and cow is of great interest both the agricultural perspective and for biomedical application. Large animal models, particularly pig, are likely to provide models of human genetic diseases and transplantation research where rodent models are inappropriate. However, establishment of ESCs establishment from pigs has remained an elusive goal. In the present study, we focused on signaling transduction regulation in pig epiblast stem cells (pEpiSCs). Pig epiblasts were isolated from early tubular stage embryos collected in vivo day 10.5～12 after insemination. Epiblasts were separated from trophoblast and underlying primitive endoderm using 21G needles and fine forceps. Epiblasts were cultured on mitomycin C (10 μl/ml) treated mouse embryonic feeder cells in Dulbecco’s modified Eagle’s medium (DMEM) containing 1% minimal essential medium (MEM) nonessential amino acids, 1% penicillin/ streptomycin, 1% glutamine, 0.007% β-mercaptoethanol, 5 ng/ml bFGF and 1 ng/ml LIF. After plating rapid differentiation of isolated epiblasts to extraembryonic cell types was visualized in most cultures but stem cells were enclosed by these differentiated cells. We have established seven pig epiblast stem cells lines (pEpiSC1-7) from Days 10.5–12 pig embryos. pEpiSC expressed the pluripotent markers including OCT4, NANOG, SOX2 and NODAL at 3-5 passage. In addition, the modification of culture condition by the inclusion of particular protein kinase inhibitor such as Akt inhibitor, PD0325091(PD), delyed rapid differentiation of pEpiSCs. These results showed that stemness of pEpiSCs can be maintained by regulation of signaling pathway. * This work was partly supported by a grant from the NPR (2011-0013703) and the Next-Generation BioGreen 21 Program (No. PJ008209), Rural Development Administration, Republic of Korea.

본 연구는 한우 성체 유래 귀세포(Korean bovine ear skin fibroblasts, KbESF)와 태아 섬유아세포(Korean bovine fetal fibroblasts, KbFF)를 이용한 체세포 복제(SCNT) 시 세포종류, 배양기간 그리고 융합방법이 핵이식 수정란의 발달에 미치는 영향을 알아보기 위하여 실시하였다. 태아 섬유아세포는 임신 51일령의 한우태아에서 분리하였고, 귀세포는 28개월령의 성우의 귀에서 채취하였다. 세포는 15주 동안 체외에서 배양하며 체세포 핵이식(SCNT)에 공시하였다. 융합방법을 비교하기 위해 챔버방법과 전극 바늘을 이용한 방법으로 핵과 세포질을 융합하였다. 세포의 doubling time은 KbFF에서 17.3시간, KbESF에서 24.3시간으로 나타났다. 핵이식 후 융합과 분할율은 needle 방법에서 보다 유의적으로 높았으나(각 각 76.1과 81.2%, P<0.05), 배반포 발달율은 차이가 없었다. KbESF의 경우, 배반포 발달율은 passage 5~9(39.4%)와 13~15(40.4%)에서 passage 1~4에 비하여 유의적으로 높았다(P<0.05). KbFF의 경우, 융합율은 passage 5~8과 13~15에서 각각 75.0 및 76.8%로 passage 1~4(61.5%)보다 높았으나, 난분할율과 배반포 발달율은 차이가 없었다. 결론적으로, SCNT 수정란의 발달은 융합 방법에 의해 영향을 받을 수 있으나, 계대배양 15회까지 장기배양을 한 경우는 복제수정란의 발육에 영향을 주지 않는 것으로 판단된다.

Purpose – The purpose of this paper was to analyze the Chinese government’s announcement of the RMB’s appreciation on July 1, 2010, and its aim was to ascertain whether the appreciation has affected Chinese export prices by empirically measuring the degree of the exchange rate pass-tough on those prices. Research design, data, and methodology - Using 73 HS trade categories with cross-industry and time-series data, the panel estimation of a fixed-effects model has been applied to measure the degree and stability of any exchange rate pass-through effects. The estimation results show that the export prices of most trade categories were affected by the exchange rate changes. The pass-through effect was generally small, at about –0.485, and statistically significant in most export prices. Results - The empirical results indicate that China would lose its advantage and competitiveness in export if the RMB were appreciated continuously and rapidly because its export goods would no longer operate under strong monopolistic competition. Conclusions – The implications for China’s exchange rate policy suggest that it would be better for the RMB to appreciate slowly and gradually rather than radically. It is clear that it would be allow the capital free flow in Chinese overall economic interest to reduce the continuous appreciation pressure on the currency and pave the way for improvements in export distribution competitiveness.