Human bone marrow-derived mesenchymal stem cell gene expression patterns vary with culture conditions

BACKGROUND: Because of the heterogeneity of human mesenchymal stem cells (MSCs), methods for cell expansion in culture and the effects on gene expression are critical factors that need to be standardized for preparing MSCs. We investigated gene expression patterns of MSCs with different seeding densities and culture times. METHODS: Bone marrow-derived MSCs were plated at densities from 200 cells/cm2 to 5,000 cells/cm2, and the gene expression patterns were evaluated over time using a reverse-transcription polymerase chain reaction assay. RESULTS: The mRNA levels of factors that play a critical role in cell migration and tissue regeneration, such as podocalyxin-like protein (PODXL), alpha4-integrin, alpha6-integrin, and leukemia inhibitory factor (LIF), were higher in MSCs plated at 200 cells/cm2 than in MSCs plated at 5,000 cells/cm2. The mRNA levels of these factors gradually increased for 10 days and then decreased by day 15 in culture. MSCs seeded at 200 cells/cm2 that were cultured for 10 days expressed high levels of Oct-4 and Nanog. Indoleamine 2,3-dioxygenase, cyclooxygenase-1, and hepatocyte growth factor expression were upregulated in the presence of the proinflammatory cytokine interferon-gamma in these cells. CONCLUSION: We found differences in the gene expression patterns of MSCs under different culture conditions. MSCs from 10-day cultures seeded at a low density were efficiently expanded, expressed PODXL, alpha6-integrin, alpha4-integrin, and LIF, and maintained properties like stemness and immunomodulation. Therefore, ex vivo expansion of MSCs maintained for an adequate culture time after plating at low cell density can provide an effective regenerative medicinal strategy for cell therapies using MSCs.

Delays in Reperfusion of Patients with ST Elevation Myocardial Infarction: According to Mode of Transportation and Arrival Time

PURPOSE: The aim of this study was to evaluate the time delays in reperfusion of patients with ST elevation myocardial infarction (STEMI) according to the mode of transportation and patient arrival time. METHODS: An observational study of patients with STEMI treated with primary percutaneous coronary intervention (PCI) was performed from January 2004 to May 2009. The patients were classified into several subgroups according to the transportation method (self-transportation, EMS, and transfer) and patient arrival time (regular hours: weekdays, 7 AM~6 PM, off-hours: weekdays, 6 PM~7 AM, weekend and holiday). The symptom-to-door time (STDT), door-to-balloon time (DTBT), and the timeline to reperfusion were compared in each group. RESULTS: The median STDTs, DTBTs and the percent of the timeline to reperfusion (DTBT < or =90 min) differed significantly according to the transportation mode (p<0.001, respectively). Especially, the transfer group had longer median STDT (200 min, IQR 120~330), shorter median DTBT (80 min, IQR 66~102) and a significantly higher rate of achieving a timely DTBT (64.8%), compared to the other groups (self-transport and EMS use). Compared to the regular hour group, the offhour group had a shorter STDT (129 min vs. 180 min, p=0.016) and longer DTBT (99 min vs. 81 min, p<0.001). The percent of patients achieving a timely DTBT was much lower during off-hours (41.1% vs. 61.5%, p<0.001). CONCLUSION: The results of this study showed that the transfer group and regular hour group had a significantly shorter median DTBT, and the timeline for reperfusion was longer in the transfer group compared to the regular hour group in this study.

The Activation of ERK1/2 Via Tyrosine Kinase Pathway Attenuates TRAIL-induced Apoptosis in HeLa cell / 체질인류학회지

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) serves as an extracellular signal triggering apoptosis in tumor cells. To characterize the molecular events involved in TRAIL-induced apoptotic signaling, we investigated the role of extracellular signal-regulated kinase 1/2(ERK1/2) in the apoptosis using HeLa cells. Here we show that TRAIL pronounced ERK1/2 activation through a tyrosine kinase-dependent mechanism, subsequently elevated anti-apoptotic Bcl-2 protein levels. Pretreatment with Genistein, an inhibitor of tyrosine kinase, significantly attenuated ERK1/2 activation and enhanced cell death. Moreover, inhibition of ERK1/2 with PD98059 promoted apoptotic cell death through the down-regulation of ERK1/2 activity and Bcl-2 protein levels. Taken together, our results suggest that the activation of ERK1/2 via tyrosine kinase pathway plays a protective role as the mechanism of cellular defense through the up-regulation of Bcl-2 protein levels in TRAIL-induced apoptosis.

Down-regulated Reactive Oxygen Species by Heat Shock Protein 90 in 3-Hydroxykynurenine-induced SKN-SH Cell Death / 체질인류학회지

In this present study, we show that 3HK-induced reactive oxygen species (ROS) accumulation and caspase activation lead to apoptotic cell death. Pretreatment with N-acetylcysteine (NAC), an effective antioxidant, significantly attenuated 3HK-induced apoptosis by way of a reduction of ROS accumulation and caspase activity. SKN-SN cells were protected from 3HK-induced cytotoxicity by heat shock protein (HSP). HSP90 effectively attenuated 3HK-mediated ROS accumulation and apoptosis. In addition, the protective effect of HSP90 was abolished by pretreatment with HSP90 anti-sense oligonucleotide, but not when pretreated with anti-senses for other HSPs. These results suggest that HSP90 protects SKN-SH cells from 3HK-induced cytotoxicity by reducing ROS levels and caspase activity.