Phospholipids reacylation and palmitoylcoa control tumour necrosis factor-alpha sensitivity

From the hypothesis that in TNF-alpha -resistant cells the activity of mito chondrial phospholipase A2 could be reversed by a lysophospholipid acyltran sferase, we report that the mitochondrial reacylation of phosphatidylcholin e as phosphatidylethanolamine was considerably higher in C6 (TNF-alpha -res istant) than in WEHI-164 (TNF-alpha -sensitive) cells. TNF-alpha did not mo dify the phospholipids' reacylation in C6, while in WEHI-164 it was increas ed several-fold. These results suggest that TNF-alpha is not sufficient to restore the barrier permeability in sensitive cells, but may be enough to e xplain the absence of permeability change in resistant cells, AcylCoA ester s, depending on whether the acyl group is unsaturated or saturated (palmiti c acid), could control membrane permeability either by participating in the reacylation of phospholipids or keeping the pore in a closed state. The an alysis of the endogenous acvlCoA ester pools of both cell lines show that t he amount of palmitoylCoA is higher in resistant than sensitive cell lines. TNF-alpha treatment does not change these results. (C) 2001 Academic Press .