Transplantation of Adrenal Cortical Progenitor Cells Enriched by Nile Red

BackgroundThe adrenal cortex may contain progenitor cells useful for tissue regeneration. Currently there are no established methods to isolate these cells.Material and MethodsMurine adrenal cells were sorted into a Nile-red-bright (NRbright) and a Nile-red-dim (NRdim) population of cells according to their degree of cholesterol content revealed by Nile red fluorescence. The cells were transplanted under the renal capsule to determine their ability for regeneration.ResultsThe NRbright cells contained an abundance of lipid droplets, whereas the NRdim cells contained little. The NRbright cells expressed Sf1 and the more differentiated adrenal cortical genes, including Cyp11a1, Cyp11b1, and Cyp11b2, whereas the NRdim cells expressed Sf1 but not the more differentiated adrenal cortical genes. After 56 d of implantation in unilateral adrenalectomized mice, the NRdim cells expressed Sf1 and the more differentiated adrenal cortical genes, whereas the NRbright cells ceased to express Sf1 as well as the more differentiated adrenal cortical genes. NRdim cells also proliferated in the presence of basic fibroblast growth factor.ConclusionsThe population of NRdim cells contained adrenal cortical progenitor cells that can proliferate and give rise to differentiated daughter cells. These cells may be useful for adrenal cortical regeneration.