Transplantation of adrenal cortical progenitor cells enriched by Nile red.

The adrenal cortex may contain progenitor cells useful for tissue regeneration. Currently there are no established methods to isolate these cells. Murine adrenal cells were sorted into a Nile-red-bright (NR(bright)) and a Nile-red-dim (NR(dim)) 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. The NR(bright) cells contained an abundance of lipid droplets, whereas the NR(dim) cells contained little. The NR(bright) cells expressed Sf1 and the more differentiated adrenal cortical genes, including Cyp11a1, Cyp11b1, and Cyp11b2, whereas the NR(dim) cells expressed Sf1 but not the more differentiated adrenal cortical genes. After 56 d of implantation in unilateral adrenalectomized mice, the NR(dim) cells expressed Sf1 and the more differentiated adrenal cortical genes, whereas the NR(bright) cells ceased to express Sf1 as well as the more differentiated adrenal cortical genes. NR(dim) cells also proliferated in the presence of basic fibroblast growth factor. The population of NR(dim) 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.