LncRNA HULC promotes epithelial and smooth-muscle-like differentiation of adipose-derived stem cells by upregulation of BMP9

Aims: Adipose-derived stem cells (ADSCs), a source of mesenchymal stem cells, are able to differentiate into numerous cell lineages, including epithelial and smooth muscle cells. The use of ADSCs in tissue engineering technology has become the most promising therapeutic approach for urethral reconstruction. This study aimed to explore the effect of IncRNA highly upregulated in liver cancer (HULC) on the induction of ADSCs to differentiate into epithelial and smooth-muscle-like cells. Methods: ADSCs were isolated from a male dog, and the expression of HULC in ADSCs was overexpressed by transfection with HULC expressing vector lentivirus. The transfected ADSCs were then incubated with 5 mu M ATRA or 2.5 ng/ml TGF-beta 1 and 5 ng/ml PDGF-BB for 21 days. The expression of epithelial differentiation and smooth-muscle-like differentiation markers were monitored. Besides, cross-regulation between HULC and BMP9 was detected in the differentiated epithelial cells and smooth-muscle-like cells. Results: HULC increased cell viability of ADSCs, but has no impact on ADSCs apoptosis. HULC promotes ADSCs to differentiate into epithelial and smooth-muscle-like cells, as evidenced by the increases in the expression of Uroplakin-II, AE1/AE3, alpha-SMA, SM-MHC, Calponin, and SM-22 alpha. In addition, HULC could positively regulate BMP9, and BMP9 silence abolished HULC-promoted ADSC's differentiation. Furthermore, HULC activated Wnt/beta-catenin pathway while deactivated Notch pathway. Conclusion: HULC was demonstrated to be a promoter during the epithelial and smooth-muscle-like differentiation of ADSCs via the BMP9/Wnt/beta-catenin/Notch network. This study provides the first in vitro evidence that HULC-based therapy could be a valuable approach to promote urethral reconstruction.