Functional characterization of a matrix metalloproteinase 2 gene in Litopenaeus vannamei.

Matrix metalloproteinases (MMPs) contribute to both normal and pathological tissue remodeling. They act as regulatory molecules by working in enzyme cascades as well as processing matrix proteins, cytokines, growth factors and adhesion molecules to generate fragments with biological effects. So MMPs could play distrinct roles in the process of pathogen infection. In present study, we cloned a MMP-2 (LvMMP-2) gene from Litopenaeus vannamei. LvMMP-2, highly expressed in epidermis, located to endoplasmic reticulum in S2 cells. Results of real-time RT-PCR assay showed that LvMMP-2 was induced in shrimp hemocytes upon unfolded protein response or oxidative stress, but not via heat shock treatment. It is proved that the promoter activity of LvMMP-2 was enhanced by NF-E2-related factor 2 and AP-1 factor c-Jun. Further research showed that down-regulated LvMMP-2 contributing to oxidative stress injury, could reduce the cumulative mortality of shrimps under oxidative stress. Besides, our study also indicated that LvMMP-2 was accelerated by lipopolysaccharides injection. LvMMP-2 in S2 could increase the promoter activity of several antimicrobial peptide genes, and knocked-down expression of LvMMP-2 depressed the expression of penaeidin2 and ß-Defensin. Moreover, we showed that down-regulated LvMMP-2 suppressed the cumulative mortality of shrimp infected with white spot syndrome virus (WSSV) or with Vibrio alginolyticus. Collecting results suggested that LvMMP-2 involves in shrimp innate immune response, and also contributes to tissue injury caused by WSSV infection.