Role of hypoxia in promoting migration and cell fusion of urine-derived stem cells

Abstract

Objective To explore the effect of hypoxia on cell migration and fusion of urine-derived stem cells (USCs) in vitro, and observe the changes in cytoskeleton and cell polarity during the process. Methods After USCs were cultured under normoxia (20%) or hypoxia (3%) for 48 h, cell migration were detected by cell scratch test and Transwell assay, USCs' fusion with hepatic HP14-19 and HepG2 cells were observed and determined using confocal microscopy and flow cytometry, and structure of cytoskeleton was observed with transmission electron microscopy (TEM) and phalloidin fluorescence probe. The expression of cell polarity related proteins, RhoA, Cdc42 and Rac1 was measured with immunofluorescence staining, flow cytometry and real-time PCR. Results The USCs from the hypoxia group showed stronger migration capacity and cell fusion with hepatocytes when compared with the cells from the normoxia group. The results of TEM and phalloidin fluorescence staining revealed that hypoxia induced remodeling of cytoskeleton, and regularly and well-arranged microfilament and microtubule. The results of immunofluorescence staining, flow cytometry and real-time PCR indicated that the expression levels of cell polarity related proteins RhoA, Cdc42 and Rac1 were much higher in the hypoxia group than in the normoxia group. Conclusion Hypoxia preconditioning promotes cell migration and fusion in USCs, which may be associated with cytoskeleton remodeling and up-regulation of cell polarity.

Keywords

• urine-derived stem cells
• cell migration
• cell fusion
• cell polarity
• cytoskeleton