The Protective Effects of FGF-4 on Hypoxia-mediated Apoptosis of Trophoblast Stem Cells / 체질인류학회지

Preeclampsia and fetal growth restriction are conditions associated with placental hypoperfusion and villous hypoxia. The villous response to this environment includes elevated apoptosis. Recently, trophoblast stem (TS) cells had been successfully derived. FGF-4 locates in the inner cell mass (ICM) of blastocyst and TS cells have fibroblast growth factor receptor-2 (FGFR-2). To identify whether FGF-4 protects hypoxia-induced apoptosis in TS cells, this study was carried out. TS cells were cultured up to 48 h in standard (PO2 = 20%) or hypoxic (PO2 = 3%) conditions. TS cells were very vulnerable against exposure to hypoxia for 48 h but embryonic stem (ES) cells were very resistant to hypoxiamediated apoptosis. Death of TS cells bears the typical hallmarks of apoptosis as determined by DNA laddering. FGF- 4 and epidermal growth factor (EGF) protected the hypoxia-mediated cell death of trophoblast but granulocyte-macrophage colony stimulating factor (GMSF) and transforming growth factor-beta (TGF-beta) did not protect. In conclusion, we speculate that the effects of FGF-4 on apoptosis in trophoblasts may play an important role in protecting the placenta from hypoxic injury in pregnancy related with placental hypoperfusion.

The Roles of S1P on Placental Development / 체질인류학회지

Sphingosine-1-phosphate (S1P), a bioactive sphingolipid metabolite, has various functions to affect many signalling pathways leading to cellular proliferation and differentiation and to regulate of cell migration, invasion, and angiogenesis. However, there are little reports about the relation between trophoblast stem cells and S1P. Thus, the physiologic effects of S1P on trophoblast stem (TS) cells were investigated in this study. S1P was involved in early stage development of trophoblast via upregulation of Eomesodermine mRNA expression and suppressed differentiation of TS cells through activation of extracellular-signal regulated kinase (ERK) activation. Other actions of S1P were the activation of p38 and the induction of Dlx-3 mRNA expression for angiogenesis in TS cells. Interestingly, TS cells cultured with S1P for 4 days in thrombin-fibrinogen gel culture system, specific culture system for endothelial cells, showed good healthy appearance, but TS cells cultured without S1P got severe damages. Taken together, we suggest that S1P has very important roles on placenta such as development of early stage trophoblast, suppression of differentiation, and angiogenesis on placenta.

Zinc-Induced Cell Death in H9c2 Cardiomyoblast cells / 대한해부학회지

Adriamycin (ADR) is a potent anticancer drug that causes often severe cardiomyopathy. Previous reports have demonstrated that zinc accumulation is shown in rat myocardial cells following ADR treatment. However, the mechanism and role of zinc accumulation in ADR-induced cardiomyopathy are not yet elucidated. Zinc may be one of the key executors in ADR-induced cardiomyopathy. To test this hypothesis, we examined the cytotoxic effects of zinc on various cell lines including H9c2 cardiomyoblast cells, HL-60, U937, and C(6)-glial cells. Zinc induced significant the death of H9c2 cells at 0.125 mM in a dose-dependent manner. However, zinc did not induce any cytotoxic effect on both promyelocytic leukemic HL-60 cells and monoblastoid U937 cells. The nuclear morphology of Zn(2+)-treated H9c2 cells displayed apparent chromatin condensation, but no formation of chromatin fragmentation. In addition, phosphatidylserine (PS) externalization was observed by annexin-V staining. Zinc markedly decreased the intracellular GSH level in a time-dependent manner. Exposure to 0.2 mM ZnCl(2) for 6 hr decreased the intracellular GSH content to 13% of control value. Zinc-induced death of H9c2 cells and the intracellular GSH depletion were completely prevented by the addition of exogenous GSH and NAC. These result suggests that intracellular GSH depletion is directly involved in zinc-induced cardiomyopathy.

The Role of Sek1 in Protecting NO-induced Apoptosis in H9c2 cells by Inhibiting Caspase 3 Activation / 대한해부학회지

The stress activated protein kinase, or Jun N-terminal kinase (SAPKs/JNKs), is activated in response to a variety of cellular stresses such as changes in osmolarity and metabolism, DNA damage, heat shock, ischemia, and inflammatory cytokines. Sek1 (JNKK/MKK4) is a direct activator of SAPKs/JNKs in response to environmental stresses or mitogenic factors. Thus, this study was conducted to investigate the role of Sek1 on nitric oxide (NO) induced apoptotic signaling pathway in H9c2 cell. The viability of SNP (Sodium Nitroprusside) treated inactive Sek1 kinase transfectants [Sek1/KI H9c2] is significantly decreased and SNP induce DNA fragmentation in Sek1/KI H9c2. Interestingly, concomitantly with SNP induced injuries, caspase 3-like activity is increased but caspase 1 like activity is not changed in Sek1/KI H9c2. Whereas wild type Sek1 kinase transfectants [Sek1/WT H9c2] is less susceptible to SNP induced apoptosis. In Sek1/KI H9c2, the injuries and DNA fragmentation by SNP is protected by adding Ac-DEVD-AMC, caspase 3 inhibitor. In conclusion, these results suggest that Sek1 plays a role in protecting NO-induced apoptosis and DNA fragmentaion in H9c2 cells by inhibiting caspase 3-like activation.