Expression of neurodevelopmental markers by cultured porcine neural precursor cells

Despite the increasing importance of the pig as a large animal model, little is known about porcine neural precursor cells. To evaluate the markers expressed by these cells, brains were dissected from 60-day fetuses, enzymatically dissociated, and grown in the presence of epidermal growth factor, basic fibroblast growth factor, and platelet-derived growth factor. Porcine neural precursors could be grown as suspended spheres or adherent monolayers, depending on culture conditions. Expanded populations were banked or harvested for analysis using reverse transcription-polymerase chain reaction (RT-PCR), immunocytochemistry, microarrays, and flow cytometry, and results compared with data from analogous human forebrain progenitor cells. Cultured porcine neural precursors widely expressed neural cell adhesion molecule (NCAM), polysialic acid (PSA)-NCAM, vimentin, Ki-67, and Sox2. Minority subpopulations of cells expressed doublecortin, beta-III tubulin, synapsin I, glial fibrillary acidic protein (GFAP), and aquaporin 4 (AQP4) consistent with increased lineage restriction. A human microarray detected porcine transcripts for nogoA (RTN4) and stromal cell-derived factor 1 (SDF1), possibly cyclin D2 and Pbx1, but not CD133, Ki-67, nestin, or nucleostemin. Subsequent RT-PCR showed pig forebrain precursors to be positive for cyclin D2, nucleostemin, nogoA, Pbx1, vimentin, and a faint band for SDF1, whereas no signal was detected for CD133, fatty acid binding protein 7 (FABP7), or Ki-67. Human forebrain progenitor cells were positive for all the genes mentioned. This study shows that porcine neural precursors share many characteristics with their human counterparts and, thus, may be useful in porcine cell transplantation studies potentially leading to the application of this strategy in the setting of nervous system disease and injury.