The Anti-viral Function And Mechanism Of Matrix Metalloproteinase3during Dengue Virus Infection

Dengue virus,transmitted by the Aedes aegypti and Aedes,is one of the mostwidely distributed insect-borne virus in the world. According to the statistics of WHO,50-100million dengue infections are estimated to occur each year and approximately25000people die of infection. Currently,the mechanism of dengue virus infectionremains unclear. Due to lack of effective cross-protection between serotypes and thepresence of antibody-dependent enhancement, there is still no safe and effective vaccineavailable.Therefore,the study of molecular mechanisms about host anti-dengue virusinfection is very important.Our laboratory focused on the role and mechanism of JAK-STAT pathway duringDENV infection.We studied the expression of84JAK-STAT related genes inmacrophage cell line RAW264.7cells during DENV infection. Among them, theexpression of MMP3increased by3.68fold. In order to further confirm the result fromthe PCR array, we used quantitative PCR to confirm the upregulation of MMP3inmultiple cells during DENV infection. DENV infection increased significantly in avariety of cells upon silencing MMP3. Meanwhile, over-expression MMP3can inhibitthe replication of DENV in the RAW264.7cells. All of these data suggested that MMP3has anti-DENV function.In order to understand the antiviral mechanism of MMP3, we detected theexpression of selective anti-viral cytokines in MMP3silenced cells and control cellsafter DENV infection. The expression of representative cytokine and chemokinesdecreased in MMP3siRNA treated cells compared with control cells.Immunofluorescence assay suggested that MMP3translocated from the cytoplasmto the nucleus in DENV infected cells. Dual luciferase reporter assay showed that thetranscriptional activity of NFκB was significantly impaired in MMP3silenced cellupon DENV infection;and over-expression of MMP3in DENV infected cells canstrongly activated NFκB. Based on these data, we hypothesized that MMP3may achieve antiviral effect by affecting NFκB.To further understand the impact of MMP3on NFκB, fluorescence localization and co-immunoprecipitation experiments were usedto analysis the potential interaction between MMP3and NFκB in DENV infectedcells.The result showed MMP3and NFκB could co-localize in the nucleus upon DENVinfection.Co-immunoprecipitation experiment also suggested that MMP3may interactwith NFκB in the nucleus.MMP3is composed of five structural and functional domains:the signaldomain;the propeptide domain;the catalytic domain;the hinge region and thecarboxy-terminal domain.To further detect which domain is required for the interactionof MMP3and NFκB, we expressed each domian of MMP3and performed the Co-IPexperiment. The result showed that the carboxyl-terminal domain of MMP3wasrequired for the interaction between MMP3and NFκB. Reporter assay further certifiedthe carboxyl-terminal domain of MMP3can strongly activated NFκB.This is the first study to show that MMP3,an ancient molecules,could enter thenucleus and play antiviral function.We provided new evidence for the role of MMPfamily in immune regulation.The expression level of MMP3may become diagnostictargets for dengue fever,and MMP3may be served as the target of anti-viral therapy.