A heptameric peptide isolated from the marine microalga Pavlova lutheri suppresses PMA-induced secretion of matrix metalloproteinase-9 through the inactivation of the JNK, p38, and NF-κB pathways in human fibrosarcoma cells

In this study we isolate a heptameric peptide from the marine microalga Pavlova lutheri and examine its inhibitory effect and mechanism of action on the matrix metalloproteinase-9 (MMP-9) protein in human fibrosarcoma HT1080 cells. Through consecutive rounds of purification we isolated a potent MMP-9 inhibitory peptide composed of seven amino acids: Leu-Leu-Ala-Pro-Pro-Glu-Arg (796.4 Da). We show that the mRNA and protein expression levels of MMP-9 are reduced in the presence of this purified peptide. Furthermore, we show that this peptide inhibits PMA-induced translocation of nuclear factor-κB (NF-κB) by suppressing IκB-α phosphorylation and that it suppresses the phosphorylation of the c-Jun N-terminal (JNK) and p38 mitogen-activated protein kinases (MAPKs). Our results indicate that this peptide, purified from P. lutheri, has the potential to be a valuable natural preventive agent against MMP-related diseases.