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Recently, transplantation of allogeneic and autologous cells has been used for regenerative medicine. A critical issue is monitoring migration and homing of transplanted cells, as well as engraftment efficiency and functional capability in vivo. Monitoring of superparamagnetic iron oxide (SPIO) particles by magnetic resonance imaging (MRI) has been used in animal models and clinical settings to track labeled cells. A major limitation of MRI is that the signals do not show biological characteristics of transplanted cells in vivo. Bone marrow mesenchymal stem cells (MSCs) have been extensively investigated for their various therapeutic properties, and exhibit the potential to differentiate into cells of diverse lineages. In this study, cynomolgus monkey MSCs (cMSCs) were labeled with Molday ION Rhodamine-B™ (MIRB), a new SPIO agent, to investigate and characterize the biophysical and MRI properties of labeled cMSCs in vitro and in vivo. The results indicate that MIRB is biocompatible and useful for cMSCs labeling and cell tracking by multimodality imaging. Our method is helpful for detection of transplanted stem cells in vivo, which is required for understanding mechanisms of cell therapy.

Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor critical for the regulation of many cellular functions in both normal and neoplastic cells. Here, using human glioblastoma cells, we investigated KLF4's effects on cancer cell metabolism. We found that forced KLF4 expression promotes mitochondrial fusion and induces dramatic changes in mitochondrial morphology. To determine the impact of these changes on the cellular functions following, we analyzed how KLF4 alters glioblastoma cell metabolism, including glucose uptake, glycolysis, pentose phosphate pathway, and oxidative phosphorylation. We did not identify significant differences in baseline cellular metabolism between control and KLF4-expressing cells. However, when mitochondrial function was impaired, KLF4 significantly increased spare respiratory capacity and levels of reactive oxygen species in the cells. To identify the biological effects of these changes, we analyzed proliferation and survival of control and KLF4-expressing cells under stress conditions, including serum and nutrition deprivation. We found that following serum starvation, KLF4 altered cell cycle progression by arresting the cells at the G/M phase and that KLF4 protected cells from nutrition deprivation-induced death. Finally, we demonstrated that methylation-dependent KLF4-binding activity mediates mitochondrial fusion. Specifically, the downstream targets of KLF4-mCpG binding, guanine nucleotide exchange factors, serve as the effector of KLF4-induced mitochondrial fusion, cell cycle arrest, and cell protection. Our experimental system provides a robust model for studying the interactions between mitochondrial morphology and function, mitochondrial dynamics and metabolism, and mitochondrial fusion and cell death during tumor initiation and progression.

Purpose Feeder cells from animals raise considerable concern for contamination because they are directly in contact with embryonic stem cells. Methods To address this issue we collected discarded foreskin tissue and prepared a fibroblast cell line. We transferred one parthenogenetic blastocyst on to these feeder cells, and later observed outgrowth. By this approach, we were able to derive a human parthenogenetic embryonic stem cell line successfully.Results The embryonic stem cells had normal morphology, expressed all expected cell surface markers, could differentiate to embryonic bodies upon culture in vitro, and differentiated further to derivatives of all three germ layers. Conclusion This study indicates that homologous human fibroblasts can be used as feeder cells to support not only the propagation, but also the derivation of ES cells, and this should facilitate studies of therapeutic cloning for research and clinical applications.