space environment and thyroid cell lipid domains
- Paper number
IAC-08.A1.7.-A2.7.7
- Author
Dr. Elisabetta Albi, University of Perugia, Italy
- Coauthor
Prof. Francesco Saverio Ambesi, Udine University , Italy
- Coauthor
Dr. Ilaria Bernardini, University of Perugia, Italy
- Coauthor
Dr. Elisa Bartoccini, University of Perugia, Italy
- Coauthor
Mr. Remo Lazzarini, University of Perugia, Italy
- Coauthor
Prof. Mariapia Viola Magni, University of Perugia, Italy
- Coauthor
Dr. Giuseppina Perrella, University of Udine, Italy
- Year
2008
- Abstract
It has been described that in biological membranes different lipid domains can exist in equilibrium state and can act as a platform for protein segregation and cell signalling (1). The most studied class of lipid domains is constituted by cholesterol (CHO), sphingomyelin (SM) and phosphatidylcholine (PC) enriched lipid rafts. Recently it has been shown that the radioresistance of human carcinoma cells is correlated to a defect in raft membrane clustering (2). Our previous observations demonstrated that in FRTL-5 cells, UV treatment induced an increase of neutral sphingomyelinase (N-SMase) activity, responsible for the reduction of SM content, higher in proliferating cells (TSH+) than in quiescent cells (TSH-). Differently, in the space the increase the enzyme activity of TSH+ cells was similar to that of TSH- cells, suggesting that FRTL-5 could not respond to TSH treatment slowing down the proliferative activity. The aim of the present work was to evaluate the effect of the cosmic environment on lipid domains in relation to FRTL-5 TSH+ cell activity during the 15-days on the Space Shuttle (Esperia Mission). The activity of N-SMase and the content of RNA polymerase II were evaluated in the cells whereas the lipid composition was analyzed in the culture medium at the re-entry of the shuttle, after 48 hours of cell culture at 37°C. The results confirm the values of the N-SMase activity previously obtained in the space; and the value of RNA polymerase II is very low. After 48 hours at 37°C the SMase activity and the content of RNA polymerase II increase in the cell. In the culture medium the content of phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine is similar in the two experimental conditions whereas the PC, SM and CHO content decrease in the space with respect to the medium of the cells after 48 hours at 37°C. In conclusion we show that lipid metabolism changes in the space. It is possible that in the space the cells become hungry of lipid domains that are able to make them more stable, slowing down the proliferative activity and protecting them from the damage. The data are new and original because they represent the first observation of the effect of space environment on lipid metabolism in thyroid cells and they are very important considering that during interplanetary flights the astronauts present thyroid disorders 1) Brown, D. (2006) Structure and function of membrane rafts. Int. J. Med. Microbiol. 291, 433-437. 2) Edidin, M. (2003) The state of lipid rafts: from model membrane to cells. Ann. Rev. Biophys. Biomol. Struct. 32, 257-283. 3)Bionda C, Hadchity E, Alphonse G, Chapet O, Rousson R, Rodriguez-Lafrasse C, Ardail D. Free Radic Biol Med. 2007 Sep 1;43(5):681-94. Epub 2007
- Abstract document
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