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Abstract #13748 Published in IGR 8-2
IL-1 and TNF induction of matrix metalloproteinase-3 by c-Jun N-terminal kinase in trabecular meshwork
Hosseini M; Rose AY; Song K; Bohan C; Alexander JP; Kelley MJ; Acott TSInvestigative Ophthalmology and Visual Science 2006; 47: 1469-1476
See also comment(s) by James Lindsey •
PURPOSE: The cytokines TNF and IL-1 mediate the MMP-3 increase that occurs in response to trabecular meshwork (TM) treatment by laser trabeculoplasty. This MMP-3 increase appears to play a key role in the efficacy of this treatment for open-angle glaucoma. Protein kinase Cmu and the Erk mitogen-activated protein (MAP) kinases are essential signaling components in transducing MMP-3 increases produced by treatment of TM cells with these cytokines. Here, the involvement of the JNK-MAP kinase pathway in this process was evaluated. METHODS: Porcine TM cells were treated with TNFα, IL-1α, or IL-1β. Changes in MMP-3 and MMP-9 protein levels in the media were then determined by Western immunoblot. The effect of JNK inhibitor 2 was evaluated. Changes in the level of phosphorylation of JNK, c-Jun, ATF-2, MKK4, and MKK7 were also determined at various times after TNFα or IL-1α treatment. A 2.3-kb MMP-3 promoter fragment was cloned into a secreted alkaline phosphatase reporter vector. This reporter construct was cotransfected into TM cells with a mammalian expression vector containing a dominant-negative mutant of JNK. The involvement of JNK activity in the TNFα and IL-1α induction of MMP-3 expression was then evaluated. RESULTS: TNFα, IL-1α, and IL-1β increase media MMP-3 and MMP-9 protein levels, and JNK inhibitor 2 blocks these increases. JNK1/2, MKK4, c-Jun, and ATF-2 phosphorylation levels increase in response to TNFα and IL-1α treatment. JNK inhibitor 2 pretreatment blocks these c-Jun and ATF-2 phosphorylation increases. Dominant-negative JNK dramatically reduces the MMP-3 promoter-driven reporter activity induced by these cytokines. CONCLUSIONS: JNK activity is necessary for the induction of MMP-3 and MMP-9 by TNFα, IL-1α, or IL-1β in TM cells. Phosphorylation of components of the JNK signaling pathway and of the transcription factors c-Jun and ATF-2 support a role for this pathway in the induction of MMP-3 and MMP-9 in the TM in response to these cytokines. Thus, at least three separate signal transduction pathways are necessary in this signaling event in TM cells.
Dr. M. Hosseinie, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239-4197, USA
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)