IL-1 and TNF induction of matrix metalloproteinase-3 by c-Jun N-terminal kinase in trabecular meshwork.
OBJECTIVE
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 TNFalpha, IL-1alpha, or IL-1beta. 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 TNFalpha or IL-1alpha 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 TNFalpha and IL-1alpha induction of MMP-3 expression was then evaluated.


RESULTS
TNFalpha, IL-1alpha, and IL-1beta 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 TNFalpha and IL-1alpha 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 TNFalpha, IL-1alpha, or IL-1beta 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.
Casey Eye Institute, Oregon Health & Science University, Portland, Oregon 97239-4197, USA.
Mojgan
M
Hosseini
Anastasia Y
AY
Rose
Kaili
K
Song
Cynthia
C
Bohan
J Preston
JP
Alexander
Mary J
MJ
Kelley
Ted S
TS
Acott
D051698:Activating Transcription Factor 2 / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013552:Swine; D014129:Trabecular Meshwork / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D051698:Activating Transcription Factor 2; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D016755:Proto-Oncogene Proteins c-jun; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9