The nuclear ceramide/diacylglycerol balance depends on the physiological state of thyroid cells and changes during UV-C radiation-induced apoptosis
Albi, E ; Cataldi, S ; Rossi, G ; et al. ; ASI Sponsor
Oct - 2008
DOI: 10.1016/j.abb.2008.07.018
ISSN : 1096-0384 ;
journal : Archives of biochemistry and biophysics

Volume : 478 ; Issue : 1
type: Article Journal

Abstract
Intranuclear lipid metabolism modifications in relation to cell proliferation and/or apoptosis were demonstrated in hepatocytes. The aim of this study was to establish whether nuclear lipid metabolites influence cell function in different experimental models using a rat thyroid cell line (FRTL-5) treated with UV-C radiation. After UV-C irradiation cells proliferate and undergo apoptosis in the presence of thyrotropin, are quiescent and resistant to radiation-induced apoptosis in its absence and finally are proapoptotic for nutrition withdrawal. In nuclei purified from proliferating cells, irradiation stimulates neutral-sphingomyelinase activity and inhibits sphingomyelin-synthase, phosphatidylcholine-specific phospholipase C and phosphatidylinositol-specific phospholipase C activity with a consequent increase in the ceramide/diacylglycerol ratio. This effect is marked in proapoptotic cell nuclei and low in quiescent cell nuclei. In conclusion, UV-C radiation induces apoptosis, modifying nuclear lipid metabolism in relation to the physiological state of cells.

keywords : Apoptosis; Ceramide; Neutral-sphingomyelinase; Nucleus; Reverse-sphingomyelin-synthase; Sphingomyelin-synthase; Thyroid cell; Ultraviolet rays