Research Article

Increased Haematopoietic Supportive Function of USSC from Umbilical Cord Blood Compared to CB MSC and Possible Role of DLK-1

Figure 5

Effect of DLK-1-overexpression on the haematopoiesis-supporting capacity of CB MSC. (a) Exemplarily co-culture of CD34+-cells on feeders of CB MSC and FACS-sorted CB MSC strongly overexpressing DLK-1 (CB MSCDLK  high) in multiple independent wells ( ). Within 14 days, overexpression of DLK-1 did not have a beneficial effect on expansion rates of total cells, CD34+-cells or CFU. In accordance to former results for native CB MSC, only a weak expansion of total cells was observed, while amounts of total CD34+-cells as well as CFU slightly declined over time. (b) Expression levels of haematopoietic cytokines (IGF-2, IGFBP-1, SCF, SDF-1, THPO, ANGPTL-3) were analyzed by real time PCR exemplarily for a CB MSC line in native form, after induced overexpression of DLK-1 (CB MSCDLK) as well as after further FACS-sorting for cells with high DLK-1 expression (CB MSCDLK  high), respectively. No significant differences in expression levels could be detected and results were in accordance with former data, as presented in Figure 4(b).
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(a)
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(b)