Poduval P, Sillat T, Beklen A, Kouri V P, Virtanen I, Konttinen Y T
Department of Medicine, University of Helsinki, Helsinki, Finland.
Arthritis Rheum. 2007 Dec;56(12):3959-67. doi: 10.1002/art.23072.
Normal synovial lining is composed of macrophage-like type A and fibroblast-like type B lining cells. This sheet-like structure lacks a basement membrane, but its intercellular substance contains some basement membrane components, including type IV collagen. We undertook this study to determine the alpha-chain composition of type IV collagen in normal and arthritic synovial lining, using monoclonal alpha-chain antibodies.
Samples were analyzed using avidin-biotin-peroxidase complex staining for the presence of collagen alpha1/2(IV), alpha3(IV), alpha4(IV), alpha5(IV), alpha6(IV), matrix metalloproteinase 2 (MMP-2), and MMP-9, and the enzyme activity was detected using gelatin zymography. Double immunofluorescence was performed for type IV collagen/MMP-9 and type IV collagen/CD68. Synovial fibroblasts were studied using quantitative reverse transcriptase-polymerase chain reaction.
In mildly inflamed synovium from 5 trauma patients, alpha1/2(IV) chains were strongly stained, but alpha5(IV) and alpha6(IV) chains were weakly stained. Coding messenger RNA was shown in cultured synovial fibroblasts. Basement membranes of blood vessels contained all alpha(IV) chains and served as useful positive sample controls. In the synovial lining from 5 patients with rheumatoid arthritis (RA), all alpha-chains were absent/very weakly stained. This was coupled with numerous type A lining cells containing MMP-9 (type IV collagenase), also found in synovial fluid.
Synovial lining has a unique and very limited alpha-chain composition, different from that of the vascular basement membrane, which contains all alpha-chains. This special composition and lack of nidogen are probably of relevance for the bidirectional translining diffusion. Such tentative alpha-chain-dependent adhesive and transport-regulating properties seem to be deranged in RA, probably in part due to type IV collagenases produced in the lining and/or released by transmigrating or synovial fluid neutrophils.
正常滑膜衬里由巨噬细胞样的A型和成纤维细胞样的B型衬里细胞组成。这种片状结构缺乏基底膜，但其细胞间质含有一些基底膜成分，包括IV型胶原。我们进行这项研究，使用单克隆α链抗体来确定正常和关节炎滑膜衬里中IV型胶原的α链组成。
使用抗生物素蛋白-生物素-过氧化物酶复合物染色分析样本中是否存在胶原α1/2(IV)、α3(IV)、α4(IV)、α5(IV)、α6(IV)、基质金属蛋白酶2（MMP-2）和MMP-9，并使用明胶酶谱法检测酶活性。对IV型胶原/MMP-9和IV型胶原/CD68进行双重免疫荧光检测。使用定量逆转录聚合酶链反应研究滑膜成纤维细胞。
在5名创伤患者的轻度炎症滑膜中，α1/2(IV)链染色强烈，但α5(IV)和α6(IV)链染色较弱。在培养的滑膜成纤维细胞中显示有编码信使核糖核酸。血管基底膜含有所有α(IV)链，可作为有用的阳性样本对照。在5名类风湿关节炎（RA）患者的滑膜衬里中，所有α链均缺失/染色非常弱。这与滑膜液中也发现的许多含有MMP-9（IV型胶原酶）的A型衬里细胞有关。
滑膜衬里具有独特且非常有限的α链组成，不同于含有所有α链的血管基底膜。这种特殊组成和缺乏巢蛋白可能与双向跨衬里扩散有关。这种初步的α链依赖性黏附及转运调节特性在RA中似乎紊乱，可能部分是由于衬里中产生的和/或由迁移的或滑膜液中性粒细胞释放的IV型胶原酶所致。
