Endothelinergic cells in the subependymal region of mice

Endothelin (ET) is a small peptide that activates astrocyte proliferation, regulates proliferation and migration of embryonic neural precursor cells and stimulates glioblastoma growth. We found that in mouse brain, ET and its receptor B (ETRB) were highly expressed in the subependymal zone (SEZ), an adult neurogenic niche. Cells with ET immunoreactivity (ET+ cells) selectively appeared along the lateral and dorsal walls of the lateral ventricle. They also appeared in the cingular region of the corpus callosum. Subependymal ET+ cells also displayed prominin (PRO), glial fibrillary acidic protein (GFAP) and ETRB immunoreactivities. ET+ processes traversed the ependymal epithelium and approached the ventricular lumen. Ependymal cells only showed ETRB-ir. A small but consistent number of ET+ cells displayed proliferation markers: 5-bromo-2'-deoxyuridine (BrdU) incorporation, and minichromosome maintenance protein 2 (Mcm2). Cortical injury and G-CSF increased subependymal endothelinergic cells and their proliferation markers. Our findings suggest that ET and ETRB might be associated with regulation of adult neural stem cells and their migration through neurogenic and gliogenic pathways.