Expression data from HTR-8/Svneo side population (SP) and non-side population (NSP) cells

Immature cell populations, including stem cells and progenitor cells, can be found in “side-population (SP)” cells. Although SP cells isolated from some adult tissues have been reported elsewhere, isolation and characterization of human trophoblast SP cells remained to be reported. We used microarrays to detail the global program of gene expression underlying cell differentiation and identified up-regulated genes of SP cells. HTR-8/SVneo SP cells or NSP cells were isolated using a cell sorter for RNA extraction and hybridization on Affymetrix microarrays. To obtain many SP or NSP cells, we cultured a large amount of HTR-8/SVneo cells (1×10^7 cells). The cells were labeled with 2.5µg/ml Hoechst 33342 dye (Molecular Probes, Eugene, OR) for 120 minutes at 37 ℃, either alone or in combination with 50 µmol/L verapamil (Sigma-Aldrich, ST Louis, MO). Finally, the cells were then passed through EPICS ALTRA HyPerSort (Beckman Coulter, Fullerton, CA) using dual wavelength analysis (blue, 424-444 nm; red, 675 nm) after excitation with 350 nm UV light.