Background Secretory phospholipase A2 group IIA (sPLA2-IIA) appears to be an important inflammatory mediator of cardiovascular disease and may play a pivotal role in the pathophysiology of AS. To understand whether the influence of sPLA2-IIA on proinflammantory effects in vascular endothelial cells may help comprehend the mechanism induced by the sPLA2-IIA involved in AS.
Objectives To investigate the effect of different concentrations of sPLA2-IIA on Endothelial Cells, and to investigate the signalling pathway.
Methods (1) HUVEC were cultured in three different concentrations groups (0.01, 0.1, 1 ug/ml) of sPLA2-IIA. Endothelial cell nitric oxide concentration in the supernatant was detected by kit. The mRNA expression levels of ET-1, eNOS, ICAM-1, VCAM-1 were determined by Real Time-PCR. The protein expression level were measured by Western Blot or by ELISA. (2) HUVEC cells were cultured with 1 ug/ml sPLA2-IIA and 10 nmol/l 4-BPB (Hydrolysis inhibitor) or 1 umol/l PD98059 (ERK1/2 inhibitor) or SP600125 (JNK inhibitor) or SB203580 (p38 inhibitor) or Bay11-7085 (NF-kB inhibitor) alone or combined. Parameters described in Method step 1 were measured.
Results (1) sPLA2-IIA increased the mRNA and protein expression of ICAM-1, VCAM-1 and ET-1 and decreased the level of NO in a concentration dependent way. 1 ug/ml of sPLA2-IIA dramatically decreased the mRNA expression of eNOS. The protein expression of eNOS was not affected by sPLA2-IIA. (2) 4-BPB abolished the over expression of mRNA and protein of ICAM-1, VCAM-1 and ET-1 induced by the sPLA2-IIA. 4-BPB also abolished the up- regulated mRNA of eNOS and reduced the down-regulation of NO induced by sPLA2-IIA. (3) PD98059 abolished the over expression of ICAM-1, VCAM-1 and ET-1 and reduced the down-regulation of NO induced by the sPLA2-IIA. (4) SP600125 abolished the over expression of ET-1 and reduced the down-regulation of NO induced by sPLA2-IIA. (5) SB203580 had little effect on the over expression of ICAM-1, VCAM-1 and ET-1 and down-regulation of NO induced by sPLA2-IIA. 6. Bay11-7085 abolished the over expression of ICAM-1, VCAM-1 and ET-1 induced by the sPLA2-IIA.
Conclusions (1) sPLA2-IIA induced the over expression of cytokines including ICAM-1, VCAM-1 and ET-1 in a concentration dependent manner or the repression of eNOS and NO. (2) Hydrolysis of sPLA2-IIA exactly take a part to regulate the expression of ICAM-1, VCAM-1, ET-1 and eNOS in endothelial cells. (3) sPLA2-IIA affect endothelial cells adhesion function primarily via ERK1/2 and NF-kB pathway. (4) sPLA2-IIA affect endothelial cells vasomotor function primarily via ERK1/2, JNK and NF-kB pathway.