Relationship between expression of matrix metalloproteinase-9 and feeding on jellyfish in Pampus argenteus

Matrix metalloproteinase (MMP)-9 belongs to the zinc-dependent endopeptidase family, which is associated with important inflammatory processes and plays an important role in cell metabolism, embryonic development, and wound repair. The present study was performed using Pampus argenteus individuals fed with different feeds. The full-length cDNA of the MMP-9 gene was 2783 bp and encoded 681 amino acids. The amino acid sequence analysis of Pampus argenteus MMP-9 showed that it contained a highly conserved fibronectin type II domain and heme domain, and it was evolutionarily closely related to the MMP-9 of Seriola dumerili. Real-time PCR, western blotting, and enzyme activity assay were used to analyze the expression of MMP-9 in P. argenteus under different feeding conditions, in various tissues, and on different feeding days. The results showed that the expression of MMP-9 in group A (fed with jellyfish for the first 20 days) and B’ group (fed with jellyfish for subsequent 15 days) was significantly higher than that in other groups (P < 0.05) and the expression in the kidney was significantly higher than that in other tissues (P < 0.05). The expression increased gradually with the increase in feeding time. The results suggest that MMP-9 expression is induced in P. argenteus fed with jellyfish and plays a very important role in the immune response of the body.