Cultured stem cells are sensitive to gravity changes
- Paper number
IAC-06-A1.4.01
- Author
Dr. Ludmila Buravkova, Institute for Biomedical Problems, Russia
- Coauthor
Mr. Yuri Romanov, Institute for Biomedical Problems, Russia
- Coauthor
Ms. Nataly Konstantinova, Student, Russia
- Year
2006
- Abstract
Stem cells (adult and embryonic) and precursor cells play an important role in development and regeneration. The state of these cells in vivo and in vitro is regulated by a lot of biological substances, mechanical stimuli and cellular interactions. Knowledge about gravity effects on stem cells proliferation and differentiation is important for basic life sciences and for space physiology and medicine. To estimate gravity effects we used two types of cultured stem cells: human mesenchymal stromal cells (hMSC) from bone marrow and mice embryonic stem (mESC) line R1 on fider (embryonic fibroblast monolayer). Gravity changes were simulated by long-term (4-10 days) slow clinorotation. The cultured hMSC were characterized for specific markers expression by cytofluorimetry. The cultures were composed of fibroblastoid cells negative for hemopoietic cell markers and positive for ASMA, collagen-1, fibronectin, CD54, CD105 and CD106. Previously we showed that long-term clinorotation decreased MSC proliferation, changed cell morphology and modified F-actin cytoskeleton (Buravkova et al., 2005). We did not find the significant changes in cell phenotype except for decreased expression of HLA 1 and CD105. Excretion of IL-6 into medium increased significantly after 1 day of clinorotation. The differences between experimental and control values were observed during 7 days. It should be mentioned that all shifts including cell morphology, F-actin structure and IL-6 synthesis were more intensive during 1-2 days. Remodeling of cytoskeleton started after first 4 hs and was similar to preapoptotic changes. This data suggested the modification in cell adhesion and possible commitment of MSC. We analyzed the differentiation of MSC in osteogenic medium during long-term clinorotation (2 weeks). It was observed that expression of alkaline phosphatase was higher in control MSC cultures. Our results as well as the data of others researchers (Frias, 2005, Zayzafoon, 2005) showed the sensitivity of mesenchymal precursors cells to gravity changes that could play essential role in tissue physiological regeneration and reparation after insure in space flight. Long term clinorotation did not changed mESC proliferation and ES cells formed the colonies at the same rate as a control. Only slightly decrease of ESC colony size was observed during first 24 hs of clinorotation. Cell proliferation activity in LIF+-medium was increased after long term changes in gravity stimulation. It is suggested that ESCs saved the vialability and proliferative potential. However the number of embryonic bodies after clinorotation was less than in static control. This data and delayed of cardiomyocyte appearance after ESC passage indicate on possible involvement of gravity in first stage of ESC differentiation. We could conclude that the changes observed during simulation of gravity vector randomization modify reversible the physiological status of cultured stem cells and shift (time or direction) the commitment undifferentiated cells.
- Abstract document
- Manuscript document
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