Lysophosphatidylcholine produced by the phospholipase A2 isolated from Lachesis muta snake venom modulates natural killer activity as a protein kinase C effector

摘要

We have showed that a phospholipase A_2 isolated from Lachesis muta snake venom, denoted LM-PLA_2-I, had some biological effects. Here, we examined its effects on lymphocytes. Pre-incubation of human peripheral blood lymphocytes with LM-PLA_2-I plus phosphatidylcholine (PC) stimulated the natural killer (NK) activity. This was accompanied by DNA binding of nuclear transcription factor κB and the increase in PKC activity with translocation of the enzyme from the cytoplasma into the plasma membrane. These effects were reproduced when lymphocytes were pre-incubated with commercial lysophosphatidylcholine (LPC) and abolished by stausrosporin or p-bromophenacyl bromide. Evaluation of phosphorylated PKC isoforms showed that pre-incubation with LPC activated the autophosphorylation of the PKCζ isoform. Taken together, these results confirm that the enzymatic activity of the phospholipase A_2 present in L. muta venom is for the biological activity of the snake venom, and strongly suggest that the LPC produced may be acting as a modulator of PKC isoforms.