Romanic A M, Madri J A
Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510.
J Cell Biol. 1994 Jun;125(5):1165-78. doi: 10.1083/jcb.125.5.1165.
T cell extravasation from the bloodstream into the perivascular tissue during inflammation involves transmigration through the endothelial cell layer and basement membrane into the interstitial matrix. The specific mechanisms by which T cells transmigrate, however, are poorly understood. Matrix degradation by enzymes such as 72-kD gelatinase has been implicated as an important component in tissue invasion by various types of cells. In this study, we have demonstrated that 72-kD gelatinase is induced in T cells upon adhesion to endothelial cells. We also provide evidence that the induction of 72-kD gelatinase is mediated by binding to vascular cell adhesion molecule-1 (VCAM-1). The T cells used in this study were cloned murine Th1 cells antigenic to myelin basic protein. These cells express very late antigen-4 on their cell surface and have been shown to infiltrate the brain parenchyma and cause experimental autoimmune encephalomyelitis when infused into normal mice (Baron, J. L., J. A. Madri, N. H. Ruddle, G. Hashim, and C. A. Janeway. 1993. J. Exp. Med. 177:57-68). In the experiments presented here, T cells were cocultured with VCAM-1-positive and -negative endothelial cells grown in a monolayer in order to study the expression of 72-kD gelatinase upon T cell adhesion. Additional experiments were conducted in which T cells were cocultured with VCAM-1 positive cells grown on microporous membranes suspended in transwells to study 72-kD gelatinase following T cell transmigration. T cells were also incubated with recombinant VCAM-1 in order to study the role of VCAM-1 in inducing 72-kD gelatinase. The results demonstrated that T cells adhered to both VCAM-1-positive and -negative endothelial cells. T cells that adhered to the VCAM-1-positive endothelial cells exhibited an induction in 72-kD gelatinase protein, activity, and mRNA whereas 72-kD gelatinase was not induced in the T cells that adhered to the VCAM-1-negative endothelial cells. Incubating T cells with recombinant VCAM-1 coated onto tissue culture plastic showed that T cells adhered to the molecule and that adhesion to recombinant VCAM-1 was sufficient to induce 72-kD gelatinase. Further, T cells that had transmigrated through a VCAM-1-positive endothelial cell monolayer exhibited 72-kD gelatinase activity but not mRNA expression. In addition, 72-kD gelatinase was detected on the cell surface of the transmigrated T cells by FACS analysis. In other experiments, TIMP-2 was added to the transmigration studies and was shown to reduce T cell transmigration.(ABSTRACT TRUNCATED AT 400 WORDS)
在炎症过程中，T细胞从血液中渗出进入血管周围组织，这涉及到通过内皮细胞层和基底膜迁移到间质基质中。然而，T细胞迁移的具体机制仍知之甚少。诸如72-kD明胶酶等酶引起的基质降解被认为是各类细胞组织侵袭的重要组成部分。在本研究中，我们已证明T细胞与内皮细胞黏附后会诱导产生72-kD明胶酶。我们还提供证据表明，72-kD明胶酶的诱导是通过与血管细胞黏附分子-1（VCAM-1）结合介导的。本研究中使用的T细胞是对髓鞘碱性蛋白具有抗原性的克隆小鼠Th1细胞。这些细胞在其细胞表面表达极晚期抗原-4，并且已证明当注入正常小鼠体内时会浸润脑实质并引发实验性自身免疫性脑脊髓炎（Baron, J. L., J. A. Madri, N. H. Ruddle, G. Hashim, and C. A. Janeway. 1993. J. Exp. Med. 177:57 - 68）。在此处呈现的实验中，T细胞与单层生长的VCAM-1阳性和阴性内皮细胞共培养，以研究T细胞黏附时72-kD明胶酶的表达。还进行了其他实验，其中T细胞与生长在跨孔小室中悬浮的微孔膜上的VCAM-1阳性细胞共培养，以研究T细胞迁移后的72-kD明胶酶。T细胞还与重组VCAM-1孵育，以研究VCAM-1在诱导72-kD明胶酶中的作用。结果表明，T细胞能与VCAM-1阳性和阴性内皮细胞黏附。黏附于VCAM-1阳性内皮细胞的T细胞在72-kD明胶酶蛋白、活性和mRNA水平上均有诱导，而黏附于VCAM-1阴性内皮细胞的T细胞则未诱导产生72-kD明胶酶。将T细胞与包被在组织培养塑料上的重组VCAM-1孵育表明，T细胞能与该分子黏附，且与重组VCAM-1的黏附足以诱导72-kD明胶酶。此外，穿过VCAM-1阳性内皮细胞单层迁移的T细胞表现出72-kD明胶酶活性，但无mRNA表达。另外，通过流式细胞术分析在迁移后的T细胞表面检测到了72-kD明胶酶。在其他实验中，将TIMP-2添加到迁移研究中，结果显示其可减少T细胞迁移。（摘要截短至400字）
