Regulation of the levels of human trabecular matrix metalloproteinases and inhibitor by interleukin-1 and dexamethasone.
Regulation of the levels of human trabecular matrix metalloproteinases and inhibitor by interleukin-1 and dexamethasone.
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发表时间：
1993-11
影响因子：
4.4
通讯作者：
J. Samples;J. Alexander;T. Acott
中科院分区：
文献类型：
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作者：
J. Samples;J. Alexander;T. Acott
目的小梁网细胞外基质的调节机制目前尚不清楚，可能涉及一类分泌型蛋白水解酶，即基质金属蛋白酶。由于小梁细胞外基质被认为会影响眼压，因此对两种细胞调节剂改变人眼小梁网器官外植体培养液中基质金属蛋白酶水平的能力进行了评估。方法用重组人白介素1α、地塞米松或其组合作用于骨小梁组织培养72h，收集培养液进行分析。用底物凝胶电泳法测定培养上清液中基质分解酶、72kD明胶酶A和92kD明胶酶B的活性。免疫印迹法检测基质分解素和金属蛋白酶组织抑制因子(TIMP1)的表达水平。结果未刺激外植体培养上清液中72kD明胶酶A含量显著升高，92kD明胶酶B、基质分解酶和TIMP1含量较低。在不改变明胶酶A水平的情况下，白介素1α可剂量依赖性地使明胶酶B、基质分解酶和TIMP1升高数倍。地塞米松对明胶酶A没有显著影响，对基质分解酶、明胶酶B和TIMP1只有轻微的增加。当地塞米松合用时，地塞米松以剂量依赖的方式拮抗IL-1α诱导的基质分解素、明胶酶B和TIMP1的增加。结论这些调节因子可能有助于分析该酶家族在正常小梁动态平衡中的作用，并可能在青光眼的病因中发挥作用。
PURPOSE The regulation of the trabecular meshwork's extracellular matrix is poorly understood and may involve a family of secreted proteinases, the matrix metalloproteinases. Because the trabecular extracellular matrix has been hypothesized to affect intraocular pressure, an evaluation was made of the ability of two cellular modulators to change the levels of matrix metalloproteinases in the medium of human trabecular meshwork organ explant cultures. METHODS Trabecular explant cultures were exposed to recombinant human interleukin-1 alpha, dexamethasone, or combinations thereof for 72 hours and the culture medium was collected for analysis. Levels of stromelysin, the 72 kD gelatinase A and the 92 kD gelatinase B enzyme activity in this culture medium were assayed by substrate gel electrophoresis (zymography). Stromelysin and the tissue inhibitor of metalloproteinases (TIMP1) media protein levels were analyzed using immunoblots of Western transfers. RESULTS Culture medium of unstimulated explants contains significant levels of the 72 kD gelatinase A and only low levels of the 92 kD gelatinase B, stromelysin, and TIMP1. Interleukin-1 alpha produces a dose-dependent several-fold elevation of gelatinase B, stromelysin, and TIMP1 without changing gelatinase A levels. Dexamethasone produces no significant change in gelatinase A and only small increases in stromelysin, gelatinase B, and TIMP1. When added together, dexamethasone antagonizes the interleukin-1 alpha-induced increase of stromelysin, gelatinase B, and TIMP1 in a dose-dependent manner. CONCLUSION These modulators may be useful in analyzing the roles of this enzyme family in normal trabecular homeostasis and perhaps in the etiology of glaucoma.