1. Department of Traumatology, The Third Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510240, P.R. China.
2. School of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou 510006, P.R. China.
3. The Research Center of Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, P.R. China.
4. Department of Orthopaedics & Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, P.R. China
5. Key Laboratory of Orthopaedics & Traumatology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, P.R. China.
6. Laboratory of Orthopaedics & Traumatology, Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, Guangzhou, P.R. China.
Bone fractures are very common, and above 5% of the fractures are impaired, leading to nonunions and severe disablilities. The traditional Chinese medicine Bushen Huoxue decoction (BHD) has been used to treat fracture in China. Our previous report has found that BHD promotes migration of rat mesenchymal stem cells (rMSCs) by activating Wnt5a signaling pathway. However, whether and how miRNAs are involved in modulating rMSCs migration induced by BHD has not been explored. In the present study, miRNA microarray analysis and further validation by real-time quantitative RT-PCR revealed that miR-539-5p was down-regulated in BHD-induced rMSCs. Transfection of miR-539-5p mimics suppressed rMSCs migration while the miR-539-5p inhibitor promoted rMSCs migration. Our results suggested that miR-539-5p was a negative regulator of migration of rMSCs induced by BHD. Target prediction analysis tools and Dual-luciferase reporter gene assay identified Wnt5a as a direct target of miR-539-5p. MiR-539-5p inhibited the expression of the Wnt5a and its downstream signaling molecules including JNK, PKC and CaMKII, which played a critical role in regulating migration of rMSCs. Taken together, our results demonstrate that miR-539-5p negatively regulates migration of rMSCs induced by BHD through targeting Wnt5a. These findings provide evidence that miR-539-5p should be considered as an important candidate target for the development of preventive or therapeutic approaches against bone nonunions.
Keywords: miR-539-5p, Wnt5a, rat mesenchymal stem cells (rMSCs), migration