Chemotactic Activity of SDF-1α and SLF on Fetal Liver and Adult BM HSCs

<p>HSCs were assayed for their ability to chemotax in a transwell assay in response to the chemokine SDF-1α. Migrating cells were labeled with stem cell markers and analyzed by FACS to determine the actual frequency of migrated HSCs. Like adult BM HSCs, FL HSCs migrate in response to SDF-1α (A), although at reduced levels. The optimal concentration of SDF-1α for both fetal liver and adult BM HSCs was determined to be 10 nM. The migratory effect of SLF was also assayed on FL HSCs and adult BM HSCs. FL HSCs migrate equally well to SLF as SDF-1α, while adult BM HSCs showed a lesser response to SLF. SLF and SDF-1α acted synergistically in their chemoattractive effects on FL HSCs (B). To determine whether migration was due to chemokinetic effects of SDF-1α, SLF, or both, equal concentrations of factors were added to both the top and bottom wells (T&B). Data are presented as the percentage of input HSCs that migrate to the bottom chamber for a representative migration assay, each point was performed in triplicate. These data are representative of three independent experiments. The single asterisk shows a significant increase in percent migration over basal migration (<i>p</i> < 0.05). The double asterisk shows a significant increase in percent migration over SDF-1α alone.