Tl(I) and Tl(III) induce lipid metabolism alterations in MDCK cells

MOREL GOMEZ, EMANUEL; CASALI, CECILIA IRENE; WEBER, KAREN; FAGGIONATO, DANIELA; VERSTRAETEN, SANDRA; FERNÁNDEZ TOME, MARIA DEL CARMEN

Bari

Congreso; 54th International Conference on the Biosciences of Lipids: Linking Transcription to Physiology in Lipidomics; 2013

icbl

Thallium (Tl) is a toxic heavy metal that contaminates the environment and causes several human health-related problems. Although it is well known that Tl intoxication affects several organs and tissues, being the kidney a main target of Tl toxicity, the mechanisms involved are still poorly understood. Tl has two redox states, the monovalent (Tl(I)) and trivalent (Tl(III)) cation. It has been reported that other heavy metals can disturb cellular lipids; thus in the present study we investigated if Tl may affect the metabolism of lipids in a renal epithelial (MDCK) cell line. MDCK cells were incubated in the absence or presence of 10 and 100 M of Tl(I) and Tl(III) for either 24 or 48 h. After treatments, cells were collected, counted and lipids were extracted by the Bligh-Dyer method. Chloroformic extracts were resolved by thin layer chromatography in different solvent systems to evaluate the profile of phospholipids (PLs), cholesterol (Cho) and triacylglycerides (TG). Tl(I) and Tl(III) affected lipid content but with different pattern of effects. At 10 M concentration, Tl(I) did not affect any cellular lipid but at 100 M increased total PL (28%) and Cho (30%) contents after 24 h of incubation, and 40 and 52%, respectively after 48h. TG content was decreased by 30% and increased by 80 % after 24 and 48 h of Tl(I) treatment, respectively. Cells treatment with 100 M Tl(III) caused more dramatic changes since the observed increase in both PL and Cho content was around 100% after 24h and 300 % after 48 of incubation. Also, TG content was increased by 60 and 600 % after 24 and 48 h, respectively. PL profile showed a decrease in the relative amount of phosphatidylethanolamine and sphingomyelin and increase in phosphatidylcholine. Thus it is evident that Tl not only increases cell membranes components (PL and Cho), and fatty acid storage (TG) but also changes membrane properties. Such alterations may contribute to renal dysfunction leading to Tl-induced nephrotoxicity.