MicroRNA-9 modified bone marrow-derived mesenchymal stem cells (BMSCs) repair severe acute pancreatitis (SAP) via inducing angiogenesis in rats

BACKGROUND: Severe acute pancreatitis (SAP) is an acute abdominal disease characterized by pancreatic necrosis and systemic disease. In a previous study, we showed that bone marrow-derived mesenchymal stem cells (BMSCs) can reduce SAP by secreting microRNA (miR)-9; however, the underlying mechanism remains unclear. The present study investigated the mechanism underlying BMSC-induced pancreatic regeneration. METHODS: BMSCs were isolated, and miR-9 modified/antagonized BMSCs (pri-miR-9-BMSCs/TuD-BMSCs) were generated and injected into SAP rats. The levels of inflammatory cytokines and histopathologic changes were examined using ELISA and H&E staining. Angiogenesis was analyzed by qRT-PCR, western blotting, and immunohistochemistry. Cell function tests, dual luciferase reporter assays, cell co-culture, western blotting, and cell tracing were used to explore the mechanisms underlying miR-9 induced angiogenesis. RESULTS: Pri-miR-9-BMSCs induced angiogenesis in SAP rats (Ang-1↑, TIE-2↑, and CD31↑) and repaired damaged vascular endothelial cells (VECs) in vitro, promoting angiogenesis (Ang-1↑, TIE-2↑, PI3K↑, AKT↑, p-AKT↑, CD31↑, and CD34↑). Pri-miR-9-BMSCs released miR-9 into VECs or injured pancreatic tissue, targeting the VE-cadherin gene and promoting PI3K/AKT signaling to treat SAP (VE-cadherin↓, β-catenin↓, PI3K↑, p-AKT↑), whereas antagonizing miR-9 in BMSCs did not alleviate or aggravated SAP. CONCLUSIONS: Pri-miR-9-BMSCs can repair injured pancreatic tissue by secreting miR-9 and promoting angiogenesis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13287-018-1022-y) contains supplementary material, which is available to authorized users.