Turnover of phospholipids in HUT 102 lymphoblasts and chromatographic characterization of purified lecithins after their exposure to long-wave UV light, psoralen, and UV light and psoralen.

The turnover of 32P-labeled phospholipids in HUT 102 lymphoblasts was determined after a 2 h interaction of lymphoblasts with 8-methoxypsoralen (8-MOP) (15 micrograms ml-1), longwave UV light (UVA) irradiation and PUVA (8-MOP and UVA). In parallel experiments, micellar suspensions of lyso-phosphatidylcholine (PtdC), dipalmitoyl-PtdC and dilinoleoyl-PtdC, treated in a similar manner, served for the correlative assessments of cellular lipid changes. The dark reaction, UVA irradiation and PUVA all depressed total phospholipid levels in HUT 102 cells, although only PUVA induced a statistically significant decline. Thin layer chromatography (TLC) analysis revealed that neither UVA nor 8-MOP alone triggered any significant changes in the cellular content of phosphatidylinositol (PtdI), phosphatidylinositol 4-monophosphate (PtdIP) and phosphatidylinositol 4,5-bisphosphate (PtdIP2), whereas the lyso-PtdC and PtdI content of lymphoblasts showed a two-fold increase after PUVA. The TLC analysis of lyso-PtdC and micelles of dipalmitoyl-PtdC did not reveal any detectable changes after the dark reaction with 8-MOP, UVA irradiation and PUVA. In contrast, the derivatives of dark and UVA mediated reactions of 8-MOP with dilinoleoyl-PtdC were detected by TLC. These results suggest that the formation of 8-MOP derivatives of cellular phospholipids effected by PUVA, modulates the turnover of phosphoinositides and the rate of cellular proliferation.