Inhibition of Extracellular Vesicle-Associated MMP2 Abrogates Intercellular Transfer of Hepatic miR-122 to Tissue Macrophages and Curtails Liver Inflammation
microRNA-122 (miR-122), a liver specific regulatory RNA, plays an important role in controlling metabolic homeostasis in mammalian liver cells. Interestingly, miR-122 is also a proinflammatory microRNA and when exported to tissue resident macrophage induces expression of inflammatory cytokines there. We found intercellular transfer of miR-122 in lipid exposed liver plays a role in liver inflammation. Exploring the mechanism of intercellular miR-122 transfer from hepatic cells, we detected MMP2 on the membrane of extracellular vesicles derived from hepatic cells which proved to be essential for transfer of extracellular vesicles and their miRNA content from hepatic to non-hepatic cells. Matrix metalloprotease 2 or MMP2 is a metalloproteinase that plays a key role in shaping and remodelling the extracellular matrix of human tissue by targeting degradation of matrix proteins. MMP2 was found to increase the movement of the EVs along the extracellular matrix to enhance their uptake in recipient cells. Inhibition of MMP2 restricts functional transfer of hepatic miRNAs across the hepatic and non-hepatic cell boundaries. By targeting MMP2, we could reduce the innate immune response in mammalian liver by preventing intra-tissue miR-122 transfer. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=176 SRC="FIGDIR/small/425217v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@aec3b0org.highwire.dtl.DTLVardef@1b18e87org.highwire.dtl.DTLVardef@47e75org.highwire.dtl.DTLVardef@10a48e0_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIHuman hepatocytes on exposure to high lipid export out miRNAs including proinflammatory miR-122. C_LIO_LIExtracellular miR-122 is taken up by tissue macrophages to get them activated to produce inflammatory cytokines. C_LIO_LIMMP2 present on the surface of the EVs released by hepatocyte is essential for miRNA transfer to macrophage cells C_LIO_LIInhibition of MMP2 prevents miR-122 transfer to macrophage and stops activation of recipient macrophage. C_LI