Fig 1: miRNA-27a promoted craniofacial bone regeneration and the expression of Wnt/BMP signaling activators in vivo. A The same 3D honeycomb boosted scaffolds were transplanted into the bone defects of mice calvaria. B, C Micro-computed tomography images showing enhanced mineralized tissue formation in miRNA-27a mimic-transplanted samples, miRNA-27a group significantly upregulated the bone formation compared to NC group on 14 days and 28 days (mean ± SEM, n = 6). Statistical analysis was performed using a Mann–Whitney U test. Significance levels are indicated as follows: *p < 0.05. D The bone mineral density was observed by micro-computed tomography images. E Immunohistochemical localization of signaling related molecules, BCL9, β-catenin and pSMAD1/5. F The formation of bone-like tissues was evaluated using alkaline phosphatase (ALP) and hematoxylin and eosin staining. The margins of the bone cavities are marked by red arrowheads. NB: Newly formed bone; Black arrowheads: Newly formed bone-like tissue, ALP positive area, OC positive cell; NC: miRNA mimic negative control #1; miR-27a: miRNA mimic for hsa-miRNA-27a-5p. Scale bars: 100 µm