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- Title
Docosahexaenoic acid and other fatty acids induce a decrease in pH[subi] in Jurkat T-cells.
- Authors
Aires, Virginie; Hichami, Aziz; Moutairou, Kabirou; Khan, Naim Akhtar
- Abstract
1 Docosahexaenoic acid (DHA) induced rapid (t[sub1/2]= 33s) and dose-dependent decreases in pH, in BCECF-loaded human (Jurkat)T-cells. Addition of 5-(N,N-dimethyl)-amiloride, an inhibitor of Na[Sub+/] H[sup+] exchanger, prolonged DMA-induced acidification as, a function of time, indicating that the exchanger is implicated in pH, recovery. 2 Other fatty acids like oleic acid, araehidonic acid, eicosapentaenoic acid, but not palmitic acid, also induced a fall in pH, in these cells. 3 To assess the role of calcium in the DHA-induced acidification, we conducted experiments in Ca[sup2+]-free (0% Ca[Sup2+]) and Ca[sup2+] containing 100% Ca[sup2+] buffer. We observed that there was no difference in the degree of DHA-induced transient acidification in both the experimental conditions. though pH, recovery was faster in 0% Ca[sub2+] medium than that in 100% Ca[sub2+] medium. 4 In the presence of BAPTA. a calcium chelator. a rapid recovery of DHA-induced acidosis was observed. Furthermore, addition of CaCl[sub2] into 0% Ca[sup2+] medium curtailed DHA-evoked rapid pH, recovery. In 0% Ca[sup2+] medium, containing BAPTA. DHA did not evoke increases in [Ca[sup2+], though this fatty acid still induced a rapid acidification in these cells. These observations suggest that calcium is implicated in the long-lasting DHA-induced acidosis, 5 DHA-induced rapid acidification may be due to its deprotonation in the plasma membrane (flip-flop model), as suggested by the following observations: (1) DHA with a -COOH group induced intracellular acidification, but this fatty acid with a -COOCH[sub3] group failed to do so. and (2) DHA, but not propionic acid, -induced acidification was completely reversted by addition of tally acid-free bovine serum albumin in these cells. 6 These results suggest that DHA induces acidosis via deprotonation and Ca[sup2+] mobilization in human T-cells.
- Subjects
DOCOSAHEXAENOIC acid; T cells; CALCIUM; ACIDOSIS; MAJOR histocompatibility complex; CELL permeability
- Publication
British Journal of Pharmacology, 2003, Vol 140, Issue 7, p1217
- ISSN
0007-1188
- Publication type
Article
- DOI
10.1038/sj.bjp.0705563