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Abstract #8880 Published in IGR 5-2
Involvement of AP-1 in interleukin-1-stimulated MMP-3 expression in human trabecular meshwork cells
Fleenor DL; Pang IH; Clark AFInvestigative Ophthalmology and Visual Science 2003; 44: 3494-3501
PURPOSE: Stromelysin-1 (MMP-3) degrades extracellular matrix and increases aqueous outflow. In the trabecular meshwork (TM), interleukin (IL)-1 is a potent inducer of MMP-3 expression. In different cells, IL-1 activates different signaling pathways, such as nuclear factor (NF)-B-mediated protein expression, the phospholipase A2 (PLA2)-activated arachidonate cascade, and activator protein (AP)-1-associated transcription. In the present study, pharmacological tools were used to delineate the signaling mechanism involved in the effect of IL-1 on MMP-3 production in human TM cells compared with other ocular cells. METHODS: Human TM and three other ocular cells (ciliary muscle, corneoscleral fibroblast, and lamina cribrosa) were cultured in 24-well plates in the presence or absence of IL-1, with or without specific inhibitors of selected signaling pathways. Secreted proMMP-3 was quantified by ELISA, and MMP-3 activity was assayed by casein zymography. RESULTS: IL-1 (5 ng/ml) increased proMMP-3 levels in human TM cells to ten- to 38-fold of control (p < 0.001). The effect of IL-1 was blocked by Gö6976, a protein kinase Cμ (PKCμ) inhibitor; PD98059, a mitogen-activated protein kinase kinase (MEK) inhibitor; SB202190, a p38 inhibitor; and SR11302, an AP-1 inhibitor; but not by inhibitors of casein kinase II, NFB, PLA2, phospholipase D (PLD), cyclooxygenases, lipoxygenase, or sphingomyelinase. SR11302 did not inhibit the effect of IL-1 on MMP-3 production in the other ocular cells tested. CONCLUSIONS: Based on the pharmacological effects of the inhibitors, the data indicate that activation of PKCμ, MEK, and p38 leading to the activation of AP-1 is critical to the IL-1-stimulated upregulation of MMP-3 in human TM cells. Therefore, it is likely that compounds that activate the AP-1 pathway would upregulate the production of MMP-3 and improve aqueous outflow.
Dr. D.L. Fleenor, Alcon Research, Ltd., Fort Worth, TX, USA
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.7 Biochemistry (Part of: 3 Laboratory methods)
3.8 Pharmacology (Part of: 3 Laboratory methods)
