Characterization of a cerebellar granule progenitor cell line, EtC.1, and its responsiveness to 17-β-estradiol

Mouse cerebellar development occurs at late embryonic stages and through the first few weeks of postnatal life. Hormones such as 17-β-estradiol (E2) have been implicated in cerebellar development, through the expression of E2 receptors (ER). However, the role of E2 in the development and function of cerebellar neurons has yet to be fully elucidated. To gain insight into E2's actions on the developing cerebellum, we characterized a cloned neuronal cell line, EtC.1, derived from late embryonic cerebellum for its neural properties and responsiveness to E2. Our results revealed that EtC.1 cells express markers characteristic of neural progenitor cells such as Nestin, Musashi, and Doublecortin (DCX), and of the granule cell lineage such as Math1 and Zipro1. The ER alpha and beta (ERα and ERβ) were also identified in this cell line. Functionality of ERs was verified using an Estrogen Response Element (ERE)-Luciferase reporter plasmid. E2 modulated ERα, FMRP, and IL-6, which were expressed in these cells. However, E2 did not induce changes in neural proteins nor induce maturation of EtC.1 cells. CREB and ERK1/2 protein kinases were not modulated by E2 either. Interestingly, EtC.1 expressed active p450 Aromatase (P450arom), which was confirmed by the aromatization of androstenedione (AD) to E2 and other estrogen metabolites. Collectively, our results show that the EtC.1 cell line may serve as a model to study early development of cerebellar progenitor granule cells, and their responsiveness to E2.