Subramaniyam Devipriya, Virtala Robert, Pawłowski Krzysztof, Clausen Ib Groth, Warkentin S, Stevens Tim, Janciauskiene Sabina
Department of Clinical Sciences, University Hospital Malmö, Lund University, S-20502 Malmö, Sweden.
Int J Biochem Cell Biol. 2008;40(2):258-71. doi: 10.1016/j.biocel.2007.07.016. Epub 2007 Aug 6.
Endothelial cells are among the main physiological targets of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). In endothelial cells TNF-alpha elicits a broad spectrum of biological effects including differentiation, proliferation and apoptosis. alpha1-antitrypsin (AAT), an endogenous inhibitor of serine proteases plays a vital role in protecting host tissue from proteolytic injury at sites of inflammation. Recently, it has been shown that AAT can be internalized by pulmonary endothelial cells, raising speculation that it may modulate endothelial cell function in addition to suppressing protease activity. Using Affymetrix microarray technology, real time PCR and ELISA methods we have investigated the effects of AAT on un-stimulated and TNF-alpha stimulated human primary lung microvascular endothelial cell gene expression and protein secretion. We find that AAT and TNF-alpha generally induced expression of distinct gene families with AAT exhibiting little activity in terms of inflammatory gene expression. Approximately 25% of genes up regulated by TNF-alpha were inhibited by co-administration of AAT including TNF-alpha-induced self expression. Surprisingly, the effects of AAT on TNF-alpha-induced self expression was inhibited equally well by oxidized AAT, a modified form of AAT, which lacks serine protease inhibitor activity. Overall, the pattern of gene expression regulated by native and oxidized AAT was similar with neither inducing pro-inflammatory gene expression. These findings suggest that inhibitory effects of native and oxidized forms of AAT on TNF-alpha stimulated gene expression may play an important role in limiting the uncontrolled endothelial cell activation and vascular injury in inflammatory disease.
内皮细胞是促炎细胞因子肿瘤坏死因子-α（TNF-α）的主要生理靶点之一。在内皮细胞中，TNF-α引发广泛的生物学效应，包括分化、增殖和凋亡。α1-抗胰蛋白酶（AAT）是丝氨酸蛋白酶的内源性抑制剂，在保护宿主组织免受炎症部位的蛋白水解损伤中起重要作用。最近，研究表明AAT可被肺内皮细胞内化，这引发了一种推测，即它除了抑制蛋白酶活性外，还可能调节内皮细胞功能。我们使用Affymetrix微阵列技术、实时PCR和ELISA方法，研究了AAT对未刺激及TNF-α刺激的人原代肺微血管内皮细胞基因表达和蛋白分泌的影响。我们发现，AAT和TNF-α通常诱导不同基因家族的表达，AAT在炎症基因表达方面活性较低。TNF-α上调的基因中约25%在与AAT共同给药时受到抑制，包括TNF-α诱导的自身表达。令人惊讶的是，AAT对TNF-α诱导的自身表达的影响同样被氧化型AAT（AAT的一种修饰形式，缺乏丝氨酸蛋白酶抑制剂活性）很好地抑制。总体而言，天然型和氧化型AAT调节的基因表达模式相似，两者均不诱导促炎基因表达。这些发现表明，天然型和氧化型AAT对TNF-α刺激的基因表达的抑制作用，可能在限制炎症性疾病中内皮细胞的失控激活和血管损伤方面发挥重要作用。
