Cr-LAAO, an l-amino acid oxidase isolated from Calloselasma rhodosthoma snake venom, has been demonstrated as a potent stimulus for neutrophil activation and inflammatory mediator production. However, the mechanisms involved in Cr-LAAO induced neutrophil activation has not been well characterized. Here we investigated the mechanisms involved in Cr-LAAO-induced lipid body (also known as lipid droplet) biogenesis and eicosanoid formation in human neutrophils. Using microarray analysis, we show for the first time that Cr-LAAO plays a role in the up-regulation of the expression of genes involved in lipid signalling and metabolism. Those include different members of phospholipase A_2, mostly cytosolic phospholipase A₂-α (cPLA₂-α); and enzymes involved in prostaglandin synthesis including cyclooxygenases 2 (COX-2), and prostaglandin E synthase (PTGES). In addition, genes involved in lipid droplet formation, including perilipin 2 and 3 (PLIN 2 and 3) and diacylglycerol acyltransferase 1 (DGAT1), were also upregulated. Furthermore, increased phosphorylation of cPLA₂-α, lipid droplet biogenesis and PGE₂ synthesis were observed in human neutrophils stimulated with Cr-LAAO. Treatment with cPLA₂-α inhibitor (CAY10650) or DGAT-1 inhibitor (A922500) suppressed lipid droplets formation and PGE₂ secretion. In conclusion, we demonstrate for the first time the effects of Cr-LAAO to regulate neutrophil lipid metabolism and signalling.

Cr-LAAO是一种从卡洛斯拉丝红假单胞菌蛇毒中分离的1-氨基酸氧化酶，已被证明是一种有效的刺激中性粒细胞活化和炎症介质产生的方法。但是，Cr-LAAO诱导的中性粒细胞活化所涉及的机制尚未得到很好的表征。在这里，我们调查了人类中性粒细胞中Cr-LAAO诱导的脂质体（也称为脂质滴）生物发生和类花生酸形成的机制。使用微阵列分析，我们首次表明Cr-LAAO在上调参与脂质信号传导和代谢的基因表达中发挥作用。这些包括磷脂酶A _2的不同成员_，主要是胞质磷脂酶A _2- α（cPLA ₂-α）; 以及与前列腺素合成有关的酶，包括环加氧酶2（COX-2）和前列腺素E合酶（PTGES）。此外，与脂质滴形成有关的基因，包括外周血脂蛋白2和3（PLIN 2和3）和二酰基甘油酰基转移酶1（DGAT1）也被上调。此外，在用Cr-LAAO刺激的人中性粒细胞中观察到了cPLA _2- α的磷酸化增加，脂质液滴的生物发生和PGE ₂合成。用cPLA _2- α抑制剂（CAY10650）或DGAT-1抑制剂（A922500）处理可抑制脂质液滴形成和PGE ₂分泌。总之，我们首次证明了Cr-LAAO调节中性粒细胞脂质代谢和信号转导的作用。