Fucoidan increases TNF-alpha-induced MMP-9 secretion in monocytic cell line U937.
OBJECTIVE
To investigate the effect of fucoidan on the expression of matrix metalloproteinase-9 (MMP-9) from monocytes.


METHODS
Human monocytic cell line U937 was purchased from ATCC. During the experiment, FBS-free 1640 was used and U937 was cultivated with 20 ng/ml TNF-alpha and/or different concentrations of fucoidan for 24 h. RT-PCR experiments were used to determine the MMP-9 mRNA expression. ELISA and gelatin zymography detected MMP-9 amounts and activity in the supernatant. The intracellular level of MMP-9 was assayed by Western blot, and the level of CD44 on the surface was assayed by FACS.


RESULTS
In this study, we showed that pro-inflammatory cytokine TNF-alpha up-regulated U937 MMP-9 mRNA and protein levels (P < 0.05). Fucoidan can increase the TNF-alpha-induced MMP-9 secretion from U937 (P < 0.05), but no significant difference was observed in MMP-9 mRNA. The intracellular level of MMP-9 treated with TNF-alpha and fucoidan was lower (P < 0.05) than that treated with TNF-alpha alone. In addition, we demonstrated that fucoidan downregulated the surface level of CD44, the main molecule to which MMP-9 attaches.


CONCLUSIONS
We demonstrated that fucoidan post-translationally regulated MMP-9 secretion from U937. Reduced intracellular level and decreased membrane attachment may contribute to the increase in MMP-9 secretion.
Institute of Basic Medical Sciences, Qilu Hospital, Shandong University, Jinan, Shandong, People's Republic of China. jintangsun@yahoo.com.cn
Jintang
J
Sun
Alei
A
Feng
Yun
Y
Zhang
Shanzhen
S
Sun
Weixu
W
Hu
Meixiang
M
Yang
Fengcai
F
Wei
Xun
X
Qu
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D003470:Culture Media; D015536:Down-Regulation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis / Q000235:genetics; D007202:Indicators and Reagents; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects* / Q000201:enzymology*; D011134:Polysaccharides / Q000494:pharmacology*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D020298:U937 Cells
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D003470:Culture Media; D018960:Hyaluronan Receptors; D007202:Indicators and Reagents; D011134:Polysaccharides; D014409:Tumor Necrosis Factor-alpha; D012313:RNA; C007789:fucoidan; D020780:Matrix Metalloproteinase 9