Linc-ROR Modulates the Endothelial-Mesenchymal Transition of Endothelial Progenitor Cells through the miR-145/Smad3 Signaling Pathway

The endothelial-mesenchymal transition (EndMT) of endothelial progenitor cells (EPCs) plays a notable role in pathological vascular remodeling. Emerging evidence indicated that long non- coding RNA-regulator of reprogramming (linc-ROR) can promote epithelial-mesenchymal transition (EMT) in a variety of cancer cells. Nevertheless, the function of linc-ROR in EPC EndMT has not been well elucidated. The present study investigated the effect and possible mechanisms of function of linc-ROR on the EndMT of EPCs. A linc-ROR overexpression lentiviral vector (LV-linc-ROR) or a linc-ROR short hairpin RNA lentiviral vector (LV-shlinc-ROR) was used to up or downregulate linc-ROR expression in EPCs isolated from human umbilical cord blood. Functional experiments demonstrated that LV-linc-ROR promoted the proliferation and migration of EPCs, but inhibited EPC angiogenesis in vitro. In the meantime, reverse transcription- quantitative PCR and western blotting results showed that the expression of the endothelial cell markers vascular endothelialcadherin and CD31 was decreased, while the expression of the mesenchymal cell markers alpha-smooth muscle actin and SM22 alpha was increased at both mRNA and protein levels in LV-linc-RORtreated EPCs, indicating that linc-ROR induced EPC EndMT. Mechanistically, the dual-luciferase reporter assay demonstrated that microRNA (miR/miRNA)-145 was a direct target of linc-ROR, and miR-145 binds to the 3'-untranslated region of Smad3. Moreover, LV-shlinc-ROR increased the expression of miR-145, but decreased the expression of Smad3. In conclusion, linc-ROR promotes EPC EndMT, which may be associated with the miR145/Smad3 signaling pathway.