Regulation of expression of matrix metalloproteinase-9 by JNK in Raw 264.7 cells: presence of inhibitory factor(s) suppressing MMP-9 induction in serum and conditioned media

Yun-Song Lee,Quang Van Ta,Huong Thi Lan Tran

doi:10.3858/emm.2009.41.4.029

Abstract

Matrix metalloproteinase-9 (MMP-9) secreted from macrophages plays an important role in tissue destruction and inflammation through degradation of matrix proteins and proteolytic activation of cytokines/chemokines. Whereas the MEK-ERK and PI3K- Akt pathways up-regulate MMP-9 expression, regulation of MMP-9 by JNK remains controversial. Presently, we aimed to determine the role of JNK in MMP-9 regulation in Raw 264.7 cells. Inhibition of JNK by the JNK inhibitor SP600125 induced MMP-9 in the absence of serum and suppressed the expression of TNF-alpha, IL-6 and cyclooxygenase-2 in LPS-treated Raw 264.7 cells. In a knockdown experiment with small interfering RNA, suppression of JNK1 induced MMP-9 expression. Interestingly, mouse serum suppressed SP600125- mediated MMP-9 induction, similar to IFN-gamma. However, the inhibitory activity of mouse serum was not affected by pyridone 6, which inhibits Janus kinase downstream to IFN-gamma. In addition to mouse serum, conditioned media of Raw 264.7 cells contained the inhibitory factor(s) larger than 10 kDa, which suppressed SP600125- or LPS-induced MMP-9 expression. Taken together, these data suggest that JNK1 suppresses MMP-9 expression in the absence of serum. In addition, the inhibitory factor(s) present in serum or secreted from macrophages may negatively control MMP-9 expression.

Highlights

Macrophages may be crucial in inflammatory diseases including chronic obstructive pulmonary disease (Shapiro et al, 1999), atherosclerosis (Deguchi et al, 2006), arthritis (Blom et al, 2007), and tubulointerstitial kidney disease (Eardley et al, 2005) via the release of pro-inflammatory mediators
We demonstrate that JNK1, but not JNK2, suppresses LPS-induced matrix metalloproteinase-9 (MMP-9) expression in Raw 264.7 cells in the absence of serum
SP600125 augments MMP-9 induction in Raw 264.7 cells stimulated by LPS or TNF-α

Summary

Introduction

Macrophages may be crucial in inflammatory diseases including chronic obstructive pulmonary disease (Shapiro et al, 1999), atherosclerosis (Deguchi et al, 2006), arthritis (Blom et al, 2007), and tubulointerstitial kidney disease (Eardley et al, 2005) via the release of pro-inflammatory mediators. Macrophages contribute to tissue destruction by the release of several proteases including matrix metalloproteinase-9 (MMP-9; called gelatinase B) (Van de Steen et al, 2000; Vaday et al, 2001). MMP-9 modulates the activities of other proteases, growth factors, cytokines, and chemokines through proteolytic cleavage (Opdenakker et al, 2001; Atkinson et al, 2003; Lin et al, 2008). These activities indicate the important roles of MMP-9 in tissue destruction and in tissue remodeling and inflam mation. P38 MAPK up-regulates MMP-9 expression in Raw 264.7 cells stimulated with LPS (Woo et al, 2004) and CpG oligodeoxynucleotide (Lim et al, 2007)

Objectives

Methods

Results

Conclusion