Effective action distance of co-culture between umbilical cord blood-derived hematopoietic stem/progenitor cells and human adipose derived stem cells
Song KD., Liu TQ., Wu S., Guo WH., Hao YJ., Fang MY., Shi FX., Zhu LL., Ma XH., Cui ZF.
In order to investigate the effects of in vitro co-culture distance between umbilical cord blood-derived hematopoietic stem/progenitor cells (HS/PCs) and human adipose derived stem cells (h-ADSCs) on the expansion of HS/PCs and the stem cell properties of h-ADSCs, a novel transwell co-culture protocol in which the distance between the two culture chambers could be adjusted was designed. Sand papers with different specifications were utilized to adjust the cellular action distance between two kinds of cells mentioned above in the range of 10 to 450μm which was measured by a high-precision vernier caliper. Then the HS/PCs were cultured in the modified transwell supported by ADSCs for 7 days. The total cell number was counted by using a hemacytometer and the cell morphology was observed by an inverted microscope every day. After 7 days of co-culture, the expansion fold of surface antigen CD34+ and CUF-GM of the hematopoietic mononuclear cells (MNCs) were analyzed. Meanwhile, the surface markers (CD13, CD29, CD34, CD44, CD45, CD73, CD105, CD166 and HLA-DR) and the multi-differentiation potential (adipogenic, osteogenic and chondrogenic) of ADSCs were also assayed to identify the stemness of expanded stromal cells. The results show that there exists an optimal communication distance (around 350μm) between these two stem cells during their co-culture. At this distance, the expansion folds of the MNCs and CD34+ cells achieve 15.1 ± 0.2 and 5.0 ± 0.1 fold, respectively. It was found that the expanded ADSCs still show positive expression of CD29, CD44, CD166 and negative expression of CD34, CD45, and could also differentiate into osteoblasts, adipocytes and chondrocytes after respective inductions.