Sestrin 2 (SESN2) is a member of the sestrin family of stress-induced proteins that negatively regulate agingassociated biological processes. This study aims to investigate the role of SESN2 in regulating the differentiation potential and senescence of mesenchymal stem cells (MSCs) derived from young and elderly donors. Bulk RNA sequencing revealed a common decline in the SESN2 mRNA levels in MSCs from elderly individuals, which was confirmed via reverse transcription-polymerase chain reaction and western blot analyses. SESN2 knockdown in MSCs from young donors resulted in phenotypic changes similar to those in MSCs from elderly donors, including an enhanced expression of senescence and adipogenic markers and diminished expression of osteogenic markers. To confirm the effect of decreased SESN2 expression on osteogenic and adipogenic differentiation, we induced Sesn2 knockdown in mouse bone marrow-derived MSCs. Sesn2 knockdown suppressed the mRNA expression of osteogenic marker genes, alkaline phosphatase activity, and matrix mineralization. Furthermore, Sesn2 knockdown enhanced mRNA expression of the adipogenic marker genes and intracellular lipid accumulation. These results suggest that a decline in SESN2 expression during aging contributes to the shift of MSC differentiation from osteogenic to adipogenic lineage.

Three different dogs who had immune-mediated hemolytic anemia (IMHA) were treated for more than two weeks with blood transfusion in an animal clinic. Despite this treatment and hospitalization, there was no clinical improvement in clinical signs as well as complete blood cell count (CBC) including hematocrit (HCT) and C-reactive protein (CRP). All cases were then injected two or three times with allogeneic stem cells through an intravenous route for treatment. Upon administrating stem cells to the IMHA dogs, clinical conditions and the indexes of HCT and CRP were clinically improved within or close to normal ranges.

수국은 수국과(Hydrangeaceae) 수국속(Hydrangea)의 낙엽관목 식물로 크고 화려한 화형을 가져 절화, 분화 및 조 경수로 전세계적 인기가 있는 식물이다. 나무수국은 수국 (H. macrophylla)과 비교하여 삽목율이 낮은 것으로 알려져 있지만 나무수국의 묘목생산을 위한 삽목 연구 및 두 종간 삽목율 차이 원인 규명에 관한 연구는 미미하다. 본 연구는 IBA(Indol-3-butyric acid) 500mg·L-1 처리시 삽수의 침지 시간에 따른 삽목율 조사를 통해 적정 호르몬 처리 시간을 제 시하고 나무수국과 수국의 해부학적 구조 관찰을 통한 삽목율 차이 발생의 원인을 규명하고자 실시하였다. 나무수국의 적정 호르몬 처리 시간을 규명하기 위해 IBA 500mg·L-1을 무처 리, 30분, 2시간, 4시간 침지처리를 하였다. 종간 삽목율 차이 발생의 원인 규명을 위해 나무수국과 수국의 줄기 단면과 삽 목 후 시간 경과에 따른 발근을 해부학적으로 관찰하였다. 연 구의 결과 나무수국의 삽목시 IBA 500mg·L-1에 2시간 이상 침지처리가 다른 처리구와 비교하여 발근율이 높고 발생 뿌리 수가 가장 많았다. 또, 나무수국의 삽목율이 수국과 비교하여 낮은 것은 줄기의 세포 구조상 방사조직의 형태, 섬유세포의 밀도, 도관의 발달, 전분 함유 세포의 수 등에 차이가 관찰되 었고 이러한 세포 구조적 차이들의 영향으로 나무수국이 수국 보다 삽목 후 뿌리 조직 세포분열이 7일 늦게 시작되는 것이 확인되었다. 본 연구의 결과로 나무수국의 삽목 번식의 기초 자료로 활용되어 묘목 생산 효율 증대에 활용되길 바란다.

Currently, there is no treatment to reverse or cure heart failure caused by ischemic heart disease and myocardial infarction despite the remarkable advances in modern medicine. In addition, there is a lack of evidence regarding the existence of stem cells involved in the proliferation and regeneration of cardiomyocytes in adult hearts. As an alternative solution to overcome this problem, protocols for differentiating human pluripotent stem cell (hPSC) into cardiomyocyte have been established, which further led to the development of cell therapy in major leading countries in this field. Recently, clinical studies have confirmed the safety of hPSC-derived cardiac progenitor cells (CPCs). Although several institutions have shown progress in their research on cell therapy using hPSC-derived cardiomyocytes, the functions of cardiomyocytes used for transplantation remain to be those of immature cardiomyocytes, which poses a risk of graft-induced arrhythmias in the early stage of transplantation. Over the last decade, research aimed at achieving maturation of immature cardiomyocytes, showing same characteristics as those of mature cardiomyocytes, has been actively conducted using various approaches at leading research institutes worldwide. However, challenges remain in technological development for effective generation of mature cardiomyocytes with the same properties as those present in the adult hearts. Therefore, in this review, we provide an overview of the technological development status for maturation methods of hPSC-derived cardiomyocytes and present a direction for future development of maturation techniques.

Somatic cell nuclear transfer (SCNT) in pigs has been used as a very important tool to produce transgenic for the pharmaceutical protein, xenotransplantation, and disease model and basic research of cloned animals. However, the production efficiency of SCNT embryos is very low in pigs and miniature pigs. The type of donor cell is an important factor influencing the production efficiency of these cloned pigs. Here, we investigated the developmental efficiency of SCNT embryos to blastocysts and full term development using fetal fibroblasts (FF) and mesenchymal stem cells (MSCs) to identify a suitable cell type as donor cell. We isolated each MSCs and FF from the femoral region and fetus. Cultured donor cell was injected into matured embryos for cloning. After that, we transferred cloned embryos into surrogate mothers. In term of in vitro development, the SCNT embryos that used MSCs had significantly higher in cleavage rates than those of FF (81.5% vs. 72%) (p<0.05), but the blastocyst formation rates and apoptotic cell ratio was similar (15.1%, 6.18% vs. 20.8%, 9.32%). After embryo transferred to surrogates, nine and nineteen clone piglets were obtained from the MSCs and FF group, respectively, without significant differences in pregnancy and birth rate (50%, 40% vs. 52.3%, 45.4%) (p>0.05). Moreover, there was no significant difference in the corpus hemorrhagicum numbers of ovary, according to pregnancy, abortion, and delivery of surrogate mothers between MSCs and FF groups. Therefore, the MSCs and FF are useful donor cells for production of clone piglets through SCNT, and can be used as important basic data for improving the efficiency of production of transgenic clone pigs in the future.

In this study, when stem cell culture solution is used as a cosmetic ingredient, one of the most prominent problems is that the ingredients generally have low thermal stability. Therefore, in this study, in order to find out how the stem cell culture medium is heated or preserved at high temperature, the effect of various effects of stem cells on the various effects of the stem cells was investigated. Investigated. As a result of the experiment, the wound healing assay confirmed that the cell migration increased after 6 hours, and after 24 hours, it was confirmed that the cell mobility was increased and cell division was promoted, thereby being concentrated. As a result of investigating the amount of transdermal water loss by preparing a cosmetic product containing stem cell culture solution, it was confirmed that the culture solution addition group showed an improvement rate of 31% compared to the non-added group, thereby helping in skin wound recovery. As a result of this, it is considered that this point should be considered when the stem cell culture medium is used as an active ingredient in cosmetics in the future.

Mesenchymal stem cells (MSCs) have been widely used as donor cells for somatic cell nuclear transfer (SCNT) to increase the efficiency of embryo cloning. Since replicative senescence reduces the efficiency of embryo cloning in MSCs during in vitro expansion, transfection of telomerase reverse transcriptase (TERT) into MSCs has been used to suppress the replicative senescence. Here, TERT-transfected MSCs in comparison with early passage MSCs (eMSCs) and sham-transfected MSCs (sMSCs) were used to evaluate the effects of embryo cloning with SCNT in a porcine model. Cloned embryos from tMSC, eMSC, and sMSC groups were indistinguishable in their fusion rate, cleavage rate, total cell number, and gene expression levels of OCT4, SOX2 and NANOG during the blastocyst stage. The blastocyst formation rates of tMSC and sMSC groups were comparable but significantly lower than that of the eMSC group (p < 0.05). In contrast, tMSC and eMSC groups demonstrated significantly reduced apoptotic incidence (p < 0.05), and decreased BAX but increased BCL2 expression in the blastocyst stage compared to the sMSC group (p < 0.05). Therefore, MSCs transfected with telomerase reverse transcriptase do not affect the overall development of the cloned embryos in porcine SCNT, but enables to maintain embryo quality, similar to apoptotic events in SCNT embryos typically achieved by an early passage MSC. This finding offers a bioengineering strategy in improving the porcine cloned embryo quality.

The establishment of porcine embryonic stem cells (ESCs) from porcine somatic cell nuclear transfer (SCNT) blastocysts is influenced by in vitro culture day of porcine reconstructed embryo and feeder cell type. Therefore, the objective of the present study was to determine the optimal in vitro culture period for reconstructed porcine SCNT embryos and mouse embryonic fibroblast (MEF) feeder cell type for enhancing colony formation efficiency from the inner cell mass (ICM) of porcine SCNT blastocysts and their outgrowth. As the results, porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days showed significantly increased efficiency in the formation of colonies, compared to those for 7 days. Moreover, MEF feeder cells derived from outbred ICR mice showed numerically the highest efficiency of colony formation in blastocysts produced through in vitro culture of porcine SCNT embryos for 8 days and porcine ESCs with typical ESC morphology were maintained more successfully over Passage 2 on outbred ICR mice-derived MEF feeder cells than on MEF feeder cells derived from inbred C57BL/6 and hybrid B6CBAF1 mice. Overall, the harmonization of porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days and MEF feeder cells derived from outbred ICR mice will greatly contribute to the successful establishment of ESCs derived from porcine SCNT blastocysts.

Somatic cell nuclear transfer derived embryonic stem cells (NT-ESCs) have significant advantages in various fields such as genetics, embryology, stem cell science, and regenerative medicine. However, the poor establishment of NT-ESCs hinders various research. Here, we applied fasudil, a Rho-associated kinase (ROCK) inhibitor, to develop somatic cell nuclear transfer (SCNT) embryos and establish NT-ESCs. In the study, MII oocytes were isolated from female B6D2F1 mice and performed SCNT with mouse embryonic fibroblasts (MEFs). The reconstructed NT-oocytes were activated artificially, and cultured to blastocysts in KSOM supplemented with 10 μM fasudil. Further, the blastocysts were seeded on inactivated MEFs in embryonic stem cell medium supplemented with 10 μM fasudil. A total of 26% of embryos formed into blastocysts in the fasudil treated group, while this ratio was 44% in the fasudil free control group. On the other hand, 30% of blastocysts were established NT-ESCs after exposure of fasudil, which was significantly higher than the control group (10%). The results suggest that fasudil reduced blastocyst development after SCNT due to inhibition of 2 cell cleavage while improved the establishment of NT-ESCs through the anti-apoptotic pathway.

Telomeres are known as a specialized region in the end of chromosomes to protect DNA destruction, but their lengths are shortened by repetition of cell division. This telomere shortening can be preserved or be elongated by telomerase and TERT expression. Although a certain condition in the cells may affect to the cellular and molecular characteristics, the effect of differentiation induction to telomere length and telomerase activity in mesenchymal stem cells (MSCs) has been less studied. Therefore, the present study aimed to uncover periodical alterations of telomere length, telomerase activity and TERT expression in the dental pulp-derived MSCs (DP-MSCs) under condition of differentiation inductions into adipocytes and osteoblasts on a weekly basis up to 3 weeks. Shortening of telomere was significantly (p < 0.05) identified from early-middle stages of both differentiations in comparison with undifferentiated DP-MSCs by non-radioactive chemiluminescent assay and qRT-PCR method. Telomere length in undifferentiated DP-MSCs was 10.5 kb, but the late stage of differentiated DP-MSCs which can be regarded as the adult somatic cell exhibited 8.1-8.6 kb. Furthermore, the relative-quantitative telomerase repeat amplification protocol or western blotting presented significant (p < 0.05) decrease of telomerase activity since early stages of differentiations or TERT expression from middle stages of differentiations than undifferentiated state, respectively. Based on these results, it is supposed that shortened telomere length in differentiated DP-MSCs was remained along with prolonged differentiation durations, possibly due to weakened telomerase activity and TERT expression. We expect that the present study contributes on understanding differentiation mechanism of MSCs, and provides standardizing therapeutic strategies in clinical application of MSCs in the animal biotechnology.

Because mesenchymal stem cells (MSCs) maintain distinct capacities with respect to self-renewal, differentiation ability and immunomodulatory function, they have been highly considered as the therapeutic agents for cell-based clinical application. Of particular, differentiation condition alters characteristics of MSCs, including cellular morphology, expression of gene/protein and cell surface molecule, immunological property and apoptosis. However, the previous results for differentiation-related apoptosis in MSCs have still remained controversial due to varied outcomes. Therefore, the present study aimed to disclose periodical alterations of pro- and anti-apoptosis in MSCs under differentiation inductions. The human dental pulp-derived MSCs (DP-MSCs) were differentiated into adipocytes and osteoblasts during early (1 week), middle (2 weeks) and late (3 weeks) stages, and were investigated on their apoptosis-related changes by Annexin V assay, qRT-PCR and western blotting. The ratio of apoptotic cell population was significantly (p < 0.05) elevated during the early to middle stages of differentiations but recovered up to the similar level of undifferentiated state at the late stage of differentiation. In the expression of mRNA and protein, whereas expressions of pro-apoptosis-related makers (BAX and BAK) were not altered in any kind and duration of differentiation inductions, anti-apoptosis marker (BCL2) was significantly (p < 0.05) elevated even at the early stage of differentiations. The recovery of apoptotic cell population at the late stage of differentiation is expected to be associated with the response by elevation of anti-apoptotic molecules. The present study may contribute on understanding for cellular mechanism in differentiation of MSCs and provide background data in clinical application of MSCs in the animal biotechnology to develop effective and safe therapeutic strategy.

Recent research on stem cell conditioned medium (CM) has been revealed that CM could influence on the embryo development when supplemented to in vitro culture medium. However, the optimal basal medium for CM production has not determined although it is the fundamental factor of CM. The purpose of this study is to examine the effect of human derived adipose stem cell CM (hASC-CM) with different basal medium on mice embryo development after parthenogenetic activation (PA). hASC-CM was collected from 2 kinds of serum free basal medium, DMEM and KSFM, respectively on day 5 from the culture of hASC isolated from human fat tissue. Intra-peritoneal injection of PMSG and hCG was conducted into 7-week-old ICR mice for superovulation. The oocytes were recovered from the oviductal ampulla, 18 h after hCG injection, and denuded using 0.1% hyaluronidase. PA of oocytes was conducted with KSOM media including strontium chloride. The parthenotes were in vitro cultured in 3 groups: 100% KSOM (Control), 75% KSOM + 25% DMEM or KSFM without FBS (DMEM or KSFM group) and 75% KSOM + 25% hASC-CM from DMEM or KSFM (DMEM-CM or KSFM-CM group). Cleavage rate was assessed after 2 days post IVC and blastocyst formation rate was evaluated after 6 days post IVC both using stereomicroscope. Total cell number of blastocysts was counted by Hoechst staining. 1way ANOVA from Graphpad prism 5 was used for statistical analysis and the values are presented as means ± standard error of mean. As a result, blastocyst formation rate of DMEM-CM group (16.09±3.32%, P<0.05) was significantly lower than control and DMEM group (34.43±2.89% and 34.49±5.34%, P<0.05) but cleavage rate and total cell number of blastocysts showed no significant difference among groups. In case of KSFM, there was no significant difference in cleavage rate, blastocyst formation rate and total cell number of blastocysts among the control, KSFM group and KSFM-CM group. The sort of basal medium used for the CM collection affected the development of parthenotes during in vitro culture differently. Therefore, further research should be conducted to find out the alternative basal medium of CM able to improve the embryo development. This research was supported by Nature Cell (#550-20170028), Cooperative Research Program of RDA (CCAR, #PJ013954022018), Research Institute for Veterinary Science and the BK21 plus program.

Although there are several methods for establishment of stem cell line, most of them has critical limit such as, ethical problem and infectious concern. Accordingly, we investigated the cell fusion technique as a new tool to establish a stem cell line. We cultured mouse embryonic stem cell (ESC) and somatic cells. Then, these two type cells were fused by electro cell fusion that consist of three steps (AC→DC→AC). The fused cells were individually transferred into a 96-well plate and cultured in ESC culture medium for 6 ~ 7 days. Newly formed colonies were evaluated several analysis methods like morphology, alkaline phosphatase (AP) activities, expression of pluripotency marker genes and proteins, and karyotyping. The fusion efficiency from the ESC and somatic cell into colony formation was about 0.3 ~ 0.5 %. The electro cell fused (EF) new stem cell colonies (EF-SC1 ~ 4) were indicated normally round-shape morphology similarly to ESC colonies and each colonies were expressed green fluorescent protein that having somatic cells. Also, all EF-SC groups were highly expressed AP activity and pluripotency marker proteins, POU5f1, NANOG, SOX-2 and SSEA-1. In the transcription levels, all EF-SC groups were significantly higher level of expression in Pou5f1 and Nanog compared to donor cells (ESC and somatic cell) (p<0.05). In particular, the level of Pou5f1 expression was about 2-folds higher in EF-SC2 and EF-SC3 groups than in control and EF-SC1 groups (p<0.05). Also, the level of Nanog expression was very significantly higher in EF-SC2 group (3.5-folds) compared to control ESC group, and the expression levels among treatment groups were variable (ESC<EF-SC1<EF-SC4<EF-SC3<EF-SC2, p<0.05). In karyotype analysis, the results of EF-SC2 and EF-SC3 were presented the same that of ESC, while that of EF-SC1 and EF-SC4 shown aneuploid mutation in chromosome 8. Taken together, these results demonstrate that electro cell fusion technique can be used as a new method to establish of stem cell lines.

The objective of this study was to identify the proteins actively involved in the protection and repair of damaged cells, secreted by canine adipose derived mesenchymal stem cells (AT-MSCs) into the conditioned media. For this purpose, conditioned media (CM) was recovered from passage three stage canine AT-MSCs and skin fibroblasts cultured in serum free media after 24, 48 and 72 h. The extraction of exosomes was performed from 10-20 ml of CM using total exosome isolation kit. The isolated exosomes were then subjected to western analysis for the identification of annexin-I, annexin-II, histone H3 and dysferlin proteins. Results demonstrated the expression of proteins in the conditioned media isolated from canine AT-MSCs reflecting their potential in reducing the extent of damage at cellular levels. In conclusion, the conditioned media derived from canine AT-MSCs can be helpful in restoring the normal structure of cells both in vivo and in vitro conditions.

Induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) serve as a unique source for cell therapy. We investigated whether exosomes from iMSCs promote the proliferation of human keratinocytes (HaCaT) and human dermal fibroblasts (HDFs). iPSCs were established from human Wharton’s jelly MSCs and were allowed to differentiate into iMSCs. Exosomes were collected from the culture supernatant of MSCs (MSC-exo) and iMSCs (iMSC-exo), and their characteristics were investigated. Both exosome types possessed basic characteristics of exosomes and were taken up by skin cells in vitro and in vivo. A significant increase in HaCaT proliferation was observed with iMSC-exo, although both exosomes increased the viability and cell cycle progression in HaCaT and HDFs. No significant difference was observed in the closure of wound scratch and the expression of reparative genes between cells treated with the two exosome types. Both exosomes enhanced the secretion of collagen in HaCaT and HDFs; however, an increase in fibronectin level was observed only in HaCaT, and this effect was better with iMSC-exo treatment. Only iMSC-exo increased the phosphorylation of extracellular signal-regulated kinase (ERK)-1/2. Our results indicate that iMSC-exo promote the proliferation of skin cells by stimulating ERK1/2 and highlight the application of iMSCs for producing exosomes.

Musculoskeletal disorders including fracture, tendonitis, osteoarthritis, and laminitis are common diseases in racehorses that can cause large economic losses in the racehorse industry. Mesenchymal stem cells (MSCs) are being applied as new clinical tools for treatment of musculoskeletal disorders of racehorses. To investigate the immunomodulatory effects of stem cell therapy, we analyzed the anti- and pro-inflammatory factors in peripheral blood mononuclear cells of racehorses before and after stem cell application using quantitative real-time RT-PCR. The expression levels of pro-inflammatory factors (CCL5, IFN-γ, IL-2, and IL-18) were decreased while those of anti-inflammatory factors (TIMP-1, IL-10, TGF-β1, and VEGF) were increased significantly after application of equine adipose tissue-derived MSCs (eAD-MSCs) to racehorses with fracture. Moreover, the expression levels of pro-inflammatory factors (IL-2, IL-18, and TNF-α) were decreased while those of anti-inflammatory factors (TIMP-1, TIMP-2, IL-10, TGF-β1, and VEGF) increased significantly after stem cell application of eAD-MSCs in racehorses with tendonitis. After evaluating immunomodulatory effects of stem cell therapy on equine musculoskeletal disorders such as fracture and tendonitis, our results showed that expression levels of pro-inflammatory factors were decreased, while those of anti-inflammatory factors increased significantly after stem cell application of eAD-MSCs. These findings suggest that the healing effects of the stem cell therapy might be due to its modulation of inflammatory factors.

Mesenchymal stem cells (MSCs), which are present in all tissues, can differentiate into cells with various specific functions. Recently, cell-based therapies using MSCs have been increasing in the veterinary research and related fields. In this study, we investigated the cellular morphology, proliferating capacities, expression of cell surface markers such as CD13, CD34, CD44, CD45, CD90, and CD105, mesodermal differentiation potentials, and expression of senescence-related markers of p53, p21, and telomerase reverse transcriptase in equine adipose tissue-derived MSCs (eAD-MSCs) after cryopreservation. The eAD-MSCs were analyzed immediately and after being frozen in liquid nitrogen for 1 year (< 1 year, G1) and more than 3 years (> 3 years, G2), respectively. After cryopreservation for 1 - 3 years, G2 eAD-MSCs showed similar cellular morphology, proliferating capacities, and expression of cell surface markers when compared with G1 eAD-MSCs. Moreover, cryopreservation did not affect the adipogenic, chondrogenic, or osteogenic differentiation potentials of G1 and G2 eAD-MSCs. Collectively, cryopreservation for (or over) 3 years maintained the stem cell phenotype and differentiation potentials of eAD-MSCs. These results will be an advantage that can be effectively used for future development of cell-based therapies.

Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.

In this study, we investigated the effect of bisphosphonate on the osteoblastic differentiation of human dental stem cells (hDPSCs). In the first experiment, we evaluated the effect of bisphosphonate on the differentiation of hDPSCs into osteoblasts by alkaline phosphatase staining after culturing hDPSCs. As a result, on day 13, the osteogenic differentiation of hDPSC was suppressed at 5 μM in clodronate and 2 μM in zolendronate. In NBP, osteogenic differentiation is more suppressed. In second experiment, cytotoxicity and proliferation test, the cell proliferation (examined by MTT assay) was more suppressed as the concentrations of zolendronate were larger than those of alendronate and clodronate. Western blotting, a third experiment, was found that AKT phosphorylation was inhibited in cell signaling proteins involved in cell proliferation inhibition and death by bisphosphonate concentration. In human dental stem cells, bisphosphonates inhibit osteoblast differentiation, and this phenomenon is clearly observed in NBPs (zolendronate), and it has been found that it is related to AKT phosphorylation of cell signaling proteins.

This study conducted a social network analysis to investigate stem cell research which was actively being studied as an alternative for the treatment of intractable diseases due to infinite proliferation and differentiation ability. Papers was extracted from the PubMed database (DB) on the subject of ‘Induced Pluripotent Stem Cells (iPS) and Embryonic Stem Cells (ES)’, and ‘Adult Stem Cell (AS) and Mesenchymal Stem Cell (MS)’. Medical Subject Headings (MeSH) term was filtrated from each area. MeSH term of iPS and ES field was 148 (international), 71 (domestic), otherwise AS and MS were 89 (international), 78 (domestic). Keyword networks were visualized using degree centrality value and the core keywords compared. There was no difference in iPS and ES field compared with the domestic and international high-ranked keywords. Gene Therapy in the international level, Liver Regeneration and the Umbilical Cord in domestic were highly centered. In AS and MS fields, Neuron was high degree centrality both. Time lagged high ranked 30 keywords in slope were different, ‘Adipose Tissue’ increased both, otherwise ‘Stem Cell Transplantation’ did domestically. Although the absolute amounts of the research papers are different, research subjects had become similar to international trends following certain time lags. On the other hand research is conducted on the specific subjects in Korea. Keyword analysis will be useful method for searching a subject to actively being studied in stem cell research area.