Institut für Biochemie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 2, D-48149 Münster, Germany.
Brain Res. 2013 Aug 2;1524:1-11. doi: 10.1016/j.brainres.2013.05.047. Epub 2013 Jun 14.
Transmigration of neutrophils across the blood-brain barrier (BBB) to an inflamed brain tissue is an important process during neuronal inflammation. The process of neutrophil activation as well as their way of rolling along the endothelium and their transmigration is quite well understood. Nevertheless, relatively little is known about the fate of neutrophils after they have transmigrated through the endothelium. The role of the other cells of the neurovascular unit in this process is also poorly understood. Here we studied the potential of pericytes to chemo-attract neutrophils under inflammatory conditions. Quantitative real time PCR, western blot analysis, and a chemotaxis assay showed that pericytes are able to chemo-attract neutrophils by interleukin-8 (IL-8) after stimulation with lipopolysaccharides (LPS), tumor necrosis factor-alpha (TNF-α), or interleukin-1beta (IL-1β). Then, a co-culture model consisting of primary porcine brain capillary endothelial cells (PBCECs) and primary porcine brain capillary pericytes (PBCPs) was used to analyze neutrophil transmigration across the BBB. As a model for inflammation, LPS was used and the effects of the cytokines TNF-α, IL-1β, and interferon-gamma (IFN-γ) were analyzed. In general, all stimulants apart from IFN-γ were able to increase transendothelial neutrophil migration. This effect was significantly reduced by a specific inhibitor of matrix metalloproteinases (MMPs)-2 and -9. MMP-2/-9 secretion is expected to decrease adhesion to pericytes and thus support the transmigration of neutrophils. Additionally, in an adhesion experiment, we showed that MMP-2/-9 inhibition significantly enhances the adhesion of neutrophils to pericytes.
中性粒细胞穿越血脑屏障（BBB）迁移到炎症脑组织是神经元炎症过程中的一个重要过程。中性粒细胞的激活过程及其在血管内皮上滚动和迁移的方式已经得到了很好的理解。然而，对于它们穿越内皮后命运的了解相对较少。神经血管单元的其他细胞在这个过程中的作用也知之甚少。在这里，我们研究了在炎症条件下周细胞吸引中性粒细胞的潜力。实时定量 PCR、Western blot 分析和趋化性测定表明，周细胞在受到脂多糖（LPS）、肿瘤坏死因子-α（TNF-α）或白细胞介素-1β（IL-1β）刺激后能够通过白细胞介素-8（IL-8）趋化中性粒细胞。然后，使用由原代猪脑毛细血管内皮细胞（PBCEC）和原代猪脑毛细血管周细胞（PBCP）组成的共培养模型来分析中性粒细胞穿越 BBB 的迁移。作为炎症模型，使用 LPS 并分析了细胞因子 TNF-α、IL-1β 和干扰素-γ（IFN-γ）的作用。一般来说，除 IFN-γ 之外的所有刺激物都能够增加跨内皮中性粒细胞迁移。这种效应被基质金属蛋白酶（MMPs）-2 和 -9 的特异性抑制剂显著降低。MMP-2/-9 分泌预计会减少与周细胞的粘附，从而支持中性粒细胞的迁移。此外，在粘附实验中，我们表明 MMP-2/-9 抑制显著增强了中性粒细胞与周细胞的粘附。
