Padden Maureen, Leech Susie, Craig Beverly, Kirk John, Brankin Brenda, McQuaid Stephen
Conway Institute, School of Biomolecular and Biomedical Research, UCD, Dublin, Ireland.
Acta Neuropathol. 2007 Feb;113(2):177-86. doi: 10.1007/s00401-006-0145-x. Epub 2006 Oct 6.
Previously we have employed antibodies to the tight junction (TJ)-associated proteins ZO-1 and occludin to describe endothelial tight junction abnormalities, in lesional and normal appearing white matter, in primary and secondary progressive multiple sclerosis (MS). This work is extended here by use of antibodies to the independent TJ-specific proteins and junctional adhesion molecule A & B (JAM-A, JAM-B). We have also assessed the expression in MS of beta-catenin, a protein specific to the TJ-associated adherens junction. Immunocytochemistry and semiquantitative confocal microscopy for JAM-A and beta-catenin was performed on snap-frozen sections from MS cases (n=11) and controls (n=6). Data on 1,443 blood vessels was acquired from active lesions (n=13), inactive lesions (n=13), NAWM (n=20) and control white matter (n=13). In MS abnormal JAM-A expression was found in active (46%) and inactive lesions (21%), comparable to previous data using ZO-1. However, a lower level of TJ abnormality was found in MS NAWM using JAM-A (3%) compared to ZO-1 (13%). JAM-B was strongly expressed on a small number of large blood vessels in control and MS tissues but at too low a level for quantitative analysis. By comparison with the high levels of abnormality observed with the TJ proteins, the adherens junction protein beta-catenin was normally expressed in all MS and control tissue categories. These results confirm, by use of the independent marker JAM-A, that TJ abnormalities are most frequent in active white matter lesions. Altered expression of JAM-A, in addition to affecting junctional tightness may also both reflect and affect leukocyte trafficking, with implications for immune status within the diseased CNS. Conversely, the adherens junction component of the TJ, as indicated by beta-catenin expression is normally expressed in all MS and control tissue categories.
此前，我们利用针对紧密连接（TJ）相关蛋白ZO-1和闭合蛋白的抗体，描述了原发性和继发性进展型多发性硬化症（MS）患者病变及外观正常的白质中内皮紧密连接的异常情况。在此，我们通过使用针对独立的TJ特异性蛋白以及连接粘附分子A和B（JAM-A、JAM-B）的抗体，扩展了这项工作。我们还评估了β-连环蛋白（一种TJ相关黏附连接特有的蛋白）在MS中的表达情况。对MS病例（n = 11）和对照（n = 6）的速冻切片进行了JAM-A和β-连环蛋白的免疫细胞化学及半定量共聚焦显微镜检查。从活动性病变（n = 13）、非活动性病变（n = 13）、正常外观白质（NAWM，n = 20）和对照白质（n = 13）中获取了1443个血管的数据。在MS中，发现活动性病变（46%）和非活动性病变（21%）中存在JAM-A异常表达，这与之前使用ZO-1的数据相当。然而，与ZO-1（13%）相比，使用JAM-A在MS的NAWM中发现的TJ异常水平较低（3%）。JAM-B在对照和MS组织中的少数大血管上强烈表达，但水平过低无法进行定量分析。与TJ蛋白观察到的高水平异常相比，黏附连接蛋白β-连环蛋白在所有MS和对照组织类别中均正常表达。这些结果通过使用独立标记物JAM-A证实，TJ异常在活动性白质病变中最为常见。JAM-A表达的改变除了影响连接紧密性外，还可能反映并影响白细胞运输，对患病中枢神经系统内的免疫状态产生影响。相反，如β-连环蛋白表达所示，TJ的黏附连接成分在所有MS和对照组织类别中均正常表达。
