Fig. 4

Spaceflight reduces the propensity for neonatal CPCs to readily form endothelial-like tubes and express markers of terminal mesodermal derivatives. The expression of members of the BMP, Smad, and TBX families of genes was measured a and found to be elevated significantly in neonatal CPCs and modestly in adult CPCs. Following culture in biocells on the ground or the ISS for 30 days, CPCs were placed in endothelial growth media and incubated on Matrigel for 7 h to facilitate endothelial-like tube formation. The length of endothelial-like tubes formed b and the number of branches c were quantified using ImageJ for neonatal ground d and ISS e CPCs as well as for adult ground f and ISS g CPCs (ruler = 1000 µm). Changes in gene expression relevant to mesodermal derivatives were measured in CPCs cultured aboard the ISS for 12 days, indicating decreased expression of cardiomyocyte, endothelial, and osteogenic markers and increased expression of sinoatrial nodal markers h. n = 3 unique clones per group for gene expression data; n = 3 measurements of four pooled clones per group for migration assay data. Data are reported as the mean ± SEM, ***P < 0.001