Bargagna-Mohan P, Strissel K J, Fini M E
New England Medical Center, Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Invest Ophthalmol Vis Sci. 1999 Mar;40(3):784-9.
The matrix metalloproteinase gelatinase B is synthesized by cells at the leading edge of the corneal epithelium migrating to heal a wound. Recent data from the authors' laboratory suggest that excessive synthesis contributes to repair defects. The goal of the study reported here was to investigate mechanisms controlling gelatinase B production by corneal epithelial cells.
Freshly isolated cultures of corneal epithelial cells and early passage stromal fibroblasts from rabbit were used for these studies.
In a previous study, it was found that the cytokine interleukin (IL)-1alpha is released into the culture medium of corneal epithelial cells more efficiently when they are plated at low density with limited cell-cell contact than when plated at high density. In this study, we show that production of gelatinase B by these cells is similarly affected by cell plating density. However, it is further demonstrated that these two events are not dependent on one another but occur in parallel: IL-1alpha does not regulate gelatinase B production (synthesis), nor was there evidence that any other secreted autocrine cytokine acts as mediator. Instead, our data suggest that gelatinase B production is downregulated directly by high cell density and indicate a connection to the level of protein kinase C activity. Nevertheless, the anticancer agent suramin, which blocks collagenase synthesis by interfering with autocrine cytokine-receptor interactions, still inhibits synthesis of gelatinase B.
Unlike collagenase synthesis by corneal stromal fibroblasts, production (synthesis) of gelatinase B does not appear to be controlled by secreted autocrine cytokines but can still be inhibited by suramin. Suramin may make an effective therapeutic agent for controlling pathologic overproduction of gelatinase B in corneal ulcers.
基质金属蛋白酶明胶酶B由迁移至角膜上皮伤口前沿的细胞合成。作者实验室最近的数据表明，过度合成会导致修复缺陷。本文报道的这项研究的目的是探究角膜上皮细胞中控制明胶酶B产生的机制。
本研究使用了从兔新鲜分离的角膜上皮细胞培养物和早期传代的基质成纤维细胞。
在之前的一项研究中发现，角膜上皮细胞以低密度接种且细胞间接触有限时，细胞因子白细胞介素（IL）-1α更有效地释放到培养基中，而高密度接种时则不然。在本研究中，我们表明这些细胞产生明胶酶B同样受细胞接种密度的影响。然而，进一步证明这两个事件并非相互依赖，而是并行发生：IL-1α不调节明胶酶B的产生（合成），也没有证据表明任何其他分泌的自分泌细胞因子起介导作用。相反，我们的数据表明，高细胞密度直接下调明胶酶B的产生，并表明其与蛋白激酶C活性水平有关。尽管如此，通过干扰自分泌细胞因子-受体相互作用来阻断胶原酶合成的抗癌药物苏拉明，仍能抑制明胶酶B的合成。
与角膜基质成纤维细胞合成胶原酶不同，明胶酶B的产生（合成）似乎不受分泌的自分泌细胞因子控制，但仍可被苏拉明抑制。苏拉明可能成为控制角膜溃疡中明胶酶B病理性过度产生的有效治疗药物。
