Fig. 6.

Progenitor cells in the adrenal. The adrenal cortex and medulla are two cellular systems under the adrenal capsule. In the cortex, SHH⁺ and GLI1⁺ progenitors are involved in daily cell renewal and regeneration and first differentiate into zG cells and then transdifferentiate into zF cells. In the medulla, SOX10⁺ progenitors are fundamental for regeneration by differentiating into neuronal, glial, and chromaffin cells. Under stress, Nestin⁺ progenitors, which are potentially subpopulations of SHH/GLI1 cells in the cortex and SOX10 cells in the medulla, are important for synergetic remodeling and adaptation. Although the Nestin⁺ progenitors in the cortex and medulla are distinct subpopulations, they are both induced by stress in a coordinated manner. Blue arrows mark differentiation under normal conditions, red arrows mark differentiation under stress, and red double arrows mark cell–cell interactions under stress.