Modification of membrane phospholipid fatty acyl composition in a leukemic T cell line: effects on receptor mediated intracellular Ca 2+ increase

• Published in: Biochimica et biophysica acta. Molecular cell research Vol. 1092; no. 3; pp. 358 - 366
• Main Authors: Chow, S.C., Sisfontes, L., Jondal, M., Björkhem, I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1991
• Subjects: Calcium, intracellular; Fatty acid composition; Leukemic T cell; Membrane; AA; PBS; TCR; PUFA; Leukemic T cell; DCHA; AM; PtdEth; Ins(1,4,5)P 3; Fatty acid composition; UFA; BSA; OA; LA; PtdSer; ALA; EPA; FCS; Membrane; DMA; PtdIns; Calcium, intracellular; PtdCho
• ISSN: 0167-4889; 1879-2596
• DOI: 10.1016/S0167-4889(97)90013-6

The effect of modifying fatty acyl composition of cellular membrane phospholipids on receptor-mediated intracellular free Ca 2+ concentration ([Ca 2+] i) increase was investigated in a leukemic T cell line (JURKAT). After growing for 72 h in medium supplemented with unsaturated fatty acids (UFAs) and α-tocopherol, the fatty acyl composition of membrane phospholipids in JURKAT cells was extensively modified. Each respective fatty acid supplemented in the culture medium was readily incorporated into phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine in the JURKAT cells. The total n − 6 fatty acyl content was markedly reduced in phosphatidylinositol and phosphatidylcholine of cells grown in the presence of n − 3 fatty acids (α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid). Conversely, in the presence of n − 6 fatty acids (linoleic acid and arachidonic acid), the total n − 3 fatty acyl content was reduced in all the phospholipids examined. In n − 3 and n − 6 polyunsaturated fatty acid (PUFA) modified JURKAT cells, the total n − 9 monounsaturated fatty acyl content in the phospholipids were markedly reduced. Changing the fatty acyl composition of membrane phospholipids in the JURKAT cells appear to have no affect on the presentation of the T cell receptor/CD3 complex or the binding of anti-CD3 antibodies (OKT3) to the CD3 complex. However, the peak increase in [Ca 2+] i and the prolonged sustained phase elicited by OKT3 activation were suppressed in n − 3 and n − 6 PUFA but not in n − 9 monounsaturated fatty acid modified cells. In Ca 2+ free medium, OKT3-induced transient increase in [Ca 2+] i, representing Ca 2+ release from the inositol 1,4,5-triphosphate-sensitive Ca 2+ stores, were similar in control and UFA modified cells. Using Mn 2+ entry as an index of plasma membrane Ca 2+ permeability, the rate of fura-2 fluorescence quenching as a result of Mn 2+ influx stimulated by OKT3 in n − 9 monounsaturated fatty acid modified cells was similar to control cells, but the rates in n − 3 and n − 6 PUFA modified cells were significantly lower. These results suggest that receptor-mediated Ca 2+ influx in JURKAT cells is sensitive to changes in the fatty acyl composition of membrane phospholipids and n − 9 monounsaturated fatty acids appears to be important for the maintenance of a functional Ca 2+ influx mechanism.