NEAT1 promotes the repair of abdominal aortic aneurysms of endothelial progenitor cells via regulating miR-204-5p/Ang-1

To clarify the regulatory effect of Nuclear-enriched abundant transcript 1 (NEAT1) on abdominal aortic aneurysm (AAA) model rats and isolated endothelial progenitor cells (EPCs). The AAA rat model was established by CaCl stimulation, and overexpressed NEAT1 was injected into rats through tail vein. Abdominal aorta lesions and numbers of EPCs in tissues and peripheral blood were examined by hematoxylin-eosin, immunofluorescence and flow cytometry. The extracted EPCs were identified by microscopy, DiI-ac-LDL staining and flow cytometry. Effect of overexpressed/silencing NEAT1 on the viability, migration, tube formation and VEGF content of EPCs was investigated by MTT-, wound-healing, tube formation assays and ELISA, respectively. The expressions of NEAT1, miR-204-5p, Angiopoietin-1 (Ang-1)/ERK pathway were determined by qRT-PCR and Western blot as needed. The targeting relationships between NEAT1 and miR-204-5p, and miR-204-5p and Ang-1 were predicted on starBase, TargetScan and confirmed by dual-luciferase experiments. The mutual regulation effect was studied through rescue experiments. Overexpressed NEAT1 not only reduced inflammatory infiltration and increased the number of EPCs in abdominal aorta and peripheral blood, but also promoted the viability, migration, tube formation of EPCs, increased VEGF content and upregulated the expression of the Ang-1/ERK pathway in EPCs. However, silencing NEAT1 produced opposite results. NEAT1 targeting miR-204-5p inhibited the functional effects of miR-204-5p on of EPCs. Overexpressed/silencing Ang-1 partially reversed the effects of NEAT1 or miR-204-5p on the characteristics of EPCs. NEAT1 competitively binds with miR-204-5p and up-regulates Ang-1 expression in EPCs to effectively improve the proliferation, migration and angiogenesis of EPCs.