MMP-12 regulates proliferation of mouse macrophages via the ERK/P38 MAPK pathways during inflammation

MMP-12 is a metalloproteinase (MMP) mainly secreted by macrophages and regulating the degradation of the extracellular matrix. MMP-12 is related to several diseases such as emphysema, myocardial infarction and liver fibrosis. However, the functions associated with inflammation of MMP-12 in macrophages have not yet been fully investigated. Therefore, the aim of this study is to elucidate the role of MMP-12 in mouse macrophages during inflammation. Here we show by flow cytometry that MMP-12 was closely associated with the number of F4/80 + macrophages from mouse liver following exposure to LPS. Pro-inflammatory cytokines as well as the proliferation of RAW 264.7 cell line was modulated by MMP-12 knock down as illustrated by qRT-PCR, flow cytometry, CCK-8, Western Blot and EdU staining assays. Furthermore, down-regulation of MMP-12 decreased the expression and the phosphorylation levels of P38 and ERK1/2. Taken together, these data show that MMP-12 contributes to the proliferation of mouse macrophages as well as the secretion of IL-1 beta, IL-6, TNF-alpha, CXCL1 and CXCL3 through the ERK/P38 MAPK signaling pathway.