Inhibitory effect of ZPDC glycoprotein on the expression of inflammation-related cytokines through p38 MAP kinase and JNK in lipopolysaccharide-stimulated RAW 264.7 cells

Abstract:

Objective:

This study was carried out to investigate the anti-inflammatory potentials of 24 kDa glycoprotein isolated from Zanthoxylum piperitum DC fruit (ZPDC glycoprotein) in lipopolysaccharide (LPS)-stimulated murine macrophage cell line (RAW 264.7 cells).

Material and Methods:

RAW 264.7 cells were treated with ZPDC glycoprotein (50–200 μg/ml) in presence of LPS (2 μg/ml). The changes of the levels of inflammation-related factors were determined by using Western blot, EMSA, and RT-PCR.

Results:

ZPDC glycoprotein has inhibitory effects on the phosphorylation of p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK), on the DNA binding activity of activator protein-1 (AP-1), and on the expression of c-Jun and c-Fos in LPS-stimulated RAW 264.7 cells. Interestingly, the DNA binding activity of AP-1 was attenuated by treatment with inhibitors of p38 MAP kinase and JNK. In addition, ZPDC glycoprotein (200 μg/ml) not only diminished the production of superoxide anion, hydrogen peroxide, and nitric oxide, but also suppressed the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and proteins (iNOS, COX-2, and MMP-9) in LPS- stimulated RAW 264.7 cells.

Conclusions:

The present study demonstrates that ZPDC glycoprotein is a natural anti-oxidant and one of the modulators of pro-inflammatory signal transduction pathways in RAW 264.7 cells.