OBJECTIVETo discuss the effect of protein kinase C (PKC) on regulation of ecto-5'-nucleotidase activity by lysophosphatidylcholine(LPC) in human umbilical endothelial cells (HUVEC).

METHODSExperiments were conducted in HUVEC grown on dishes which were divided into 4 groups (n=15): (1) Control group in which only eAMP (5 micromol/L) was added; (2) LPC group in which HUVEC were incubated with LPC (10 micromol/L) before eAMP was added; (3) Chelerythrine group in which cells were pre-incubated with the PKC inhibitor chelerythrine (100 micromol/L) before LPC and eAMP were added; (4) alpha, beta-Methyladenosine-5'-Diphosphate (AOPCP) group in which cells were incubated with AOPCP (10 micromol/L) before eAMP was added. Etheno-adenosine production was detected at 15th, 30th, 45th min with high performance liquid chromatography(HPLC) respectively.

RESULTSComparing to the control group LPC significantly increased etheno-adenosine production at three time points respectively (P < 0.05). Furthermore, PKC inhibitor chelerythrine abolished this effect of LPC and the ethenoadenosine production at three time points were at the same level of control group (P > 0.05). CD73 inhibitor AOPCP significantly decreased the etheno-adenosine production compared to the other three groups (P < 0.01).

CONCLUSIONEcto-5'-nucleotidase can be modulated within minutes following exposure of HUVEC to LPC and this response may be mediated by PKC in HUVEC.