FIGURE 6.

ROBO1 mediates SLIT3 invasive motile effects on ntMSCs. A, Recombinant human SLIT3 promotes a general spreading of ntMSC spheroids in fibrin gel. B, ntMSCs from Slit3 ^−/− neonatal mice have decreased invasive motile activity than ntMSCs from Slit3 ^+/+ neonatal mice. ntMSCs were pooled from n = 8 animals/genotype group. C, Targeting SLIT3 transcription with siRNA inhibits ntMSC spheroid invasive sprouting. D, ROBO1 is expressed 20 to 80 times more than ROBO4 in MSCs. Each data pair represents ntMSCs and nbMSCs that were isolated from a single patient and data were compared with a ratio t test. E, ROBO1 transcript levels in paired human nbMSCs and ntMSCs as determined by qPCR and data were compared with a ratio t test. Each data pair represents ntMSCs and nbMSCs that were isolated from a single patient. F, Targeting ROBO1 transcription with siRNA inhibits ntMSC spheroid invasive sprouting. Spheroid experiment results (A, C, and F) are representative of at least four independent experiments utilizing MSCs isolated from n = 4 subjects. Data points for qPCR of siRNA treated MSCs represent technical replicates and data points for spheroid branching analysis represent a single spheroid. Spheroid experimental results were analyzed with Student's t test. Scale bars = 100 μm