The Mechanism of miR-222 Targets Matrix Metalloproteinase 1 in Regulating Fibroblast Proliferation in Hypertrophic Scars.

: This study aimed to investigate the value of miR-222 in hypertrophic scars (HS). Specific mechanisms were used to measure the level of miR-222, while MTT assay, flow cytometry, western blot and qRT-PCR were employed to detect the relative proteins after fibroblasts were transfected with the miR-222 mimic/inhibitor. The direct target of miR-222 was determined by Dual-Luciferase Reporter assay. Furthermore, qRT-PCR and western blot were employed to detect the matrix metalloproteinase 1 (MMP1) RNA/protein after fibroblasts were transfected with the miR-222 mimic/inhibitor. These results revealed that miR-222 was significantly upregulated in HS fibroblasts. The overexpression of miR-222 enhanced the HS fibroblast proliferation, increased the cell population in the S phase, inhibited the cell apoptosis, enhanced the expression levels of Col1A1, Col3A1 mRNA/protein, proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin E1 and CDK1 and reduced the expression levels of cleaved caspase-3/9. However, the miR-222 suppression triggered opposite effects. Furthermore, miR-222 played a regulatory role in HS by negatively regulating its target gene MMP1 by binding with its 3'-untranslated region. The overexpression of MMP1 reduced the expression levels of PCNA and cyclin D1, but enhanced the expression levels of cleaved caspase-3. Therefore, MiR-222 and MMP1 have potential value for HS. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.