Department of Dermatology and Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Scand J Rheumatol. 2013;42(3):241-6. doi: 10.3109/03009742.2012.733728. Epub 2013 Feb 27.
Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 has been identified as a target antigen of anti-endothelial cell immunglobulin (Ig)A antibodies in patients with Behçet's disease (BD). The aim was to investigate the effects of the sera from BD patients and Streptococcus sanguis on the subcellular expression of hnRNP A2/B1 in human dermal microvascular endothelial cells (HDMECs).
The sera of BD patients and healthy controls (HC) as well as cultured S. sanguis were used to stimulate HDMECs. Subcellular fractions were obtained from stimulated HDMECs and were subjected to immunoblot analyses. The distribution of hnRNP A2/B1 was investigated by immunocytochemistry and direct immunofluorescence study was performed in biopsy specimens of mucosal ulcers from BD patients.
BD patients' sera increased the membrane expression of hnRNP A2/B1 in HDMECs after 12 and 24 h of incubation compared with HDMECs incubated with endothelial cell culture media and HC sera. S. sanguis also increased hnRNP A2/B1 in the cellular membrane. hnRNP A2/B1 mRNA level was also significantly upregulated in HDMECs incubated with BD patients' sera and S. sanguis. Immunocytochemistry demonstrated marked expression of hnRNP A2/B1 in the cytoplasm and cellular membrane of HDMECs incubated with BD patients' sera or S. sanguis. In addition, direct immunofluorescence experiments revealed the co-localization of serum IgA antibodies and monoclonal antibodies (mAbs) against hnRNP A2/B1 in tissue sections from ulcers of BD patients.
Our data indicate that both the sera of BD patients with active disease and S. sanguis infection are inflammatory stimuli that can induce membranous hnRNP A2/B1 expression in HDMECs.
异质性核核糖核蛋白（hnRNP）A2/B1 已被鉴定为 Behçet 病（BD）患者抗内皮细胞免疫球蛋白（Ig）A 抗体的靶抗原。本研究旨在探讨 BD 患者和溶血性链球菌（S. sanguis）血清对人真皮微血管内皮细胞（HDMEC）中 hnRNP A2/B1 亚细胞表达的影响。
使用 BD 患者和健康对照（HC）的血清以及培养的 S. sanguis 刺激 HDMECs。从刺激的 HDMECs 中获得亚细胞级分，并进行免疫印迹分析。通过免疫细胞化学研究 hnRNP A2/B1 的分布，并对 BD 患者口腔黏膜溃疡活检标本进行直接免疫荧光研究。
与 HDMECs 孵育内皮细胞培养基和 HC 血清相比，BD 患者血清在孵育 12 和 24 小时后增加了 HDMEC 中 hnRNP A2/B1 的膜表达。S. sanguis 也增加了细胞表面的 hnRNP A2/B1。与 HDMECs 孵育的 BD 患者血清和 S. sanguis 也显著上调了 hnRNP A2/B1 的 mRNA 水平。免疫细胞化学显示，孵育 BD 患者血清或 S. sanguis 的 HDMECs 中 hnRNP A2/B1 在细胞质和细胞膜中表达明显。此外，直接免疫荧光实验显示 BD 患者溃疡组织切片中血清 IgA 抗体和针对 hnRNP A2/B1 的单克隆抗体（mAb）的共定位。
我们的数据表明，活动期 BD 患者的血清和 S. sanguis 感染均为炎症刺激物，可诱导 HDMEC 中膜 hnRNP A2/B1 的表达。
