Establishment and Characterization of a Brain-Derived Cell Line from Japanese Eel (Anguilla Japonica) and Transcriptomic Analysis of Its Responses to Sex Steroid Hormones.

The Japanese eel (Anguilla japonica) is an economically important aquaculture species, but cellular mechanisms underlying sex steroid responses remain poorly characterized. In this study, we established and characterized a continuous brain-derived cell line from Japanese eel, designated AJBC. The cells exhibited stable fibroblast-like morphology and continuous proliferation. Molecular characterization showed high expression of col1a1, a marker associated with fibroblast-like stromal populations, whereas neuronal and glial markers (map2, gfap, and sox2) showed low expression. The neural-associated marker nestin was detectable, indicating that AJBC cells retained certain brain-associated characteristics. AJBC cells were successfully transfected with a GFP-expressing plasmid, demonstrating their potential for genetic manipulation. Transcriptome analysis identified 3212 and 3522 differentially expressed genes following 17β-estradiol (E2) and 11-ketotestosterone (11-KT) treatment, respectively. KEGG analysis revealed enrichment of PI3K-Akt and MAPK signaling pathways, as well as cell adhesion and cytoskeletal-related processes. Representative reproductive-related genes, including sox9 and foxl2, showed differential expression following sex steroid hormone treatment. E2 increased esr1 and esr2 expression, whereas 11-KT increased ar expression, confirming the steroid-responsive characteristics of AJBC cells. This brain-derived cell line provides a useful in vitro model for investigating sex steroid-responsive molecular mechanisms and neuroendocrine-related processes in Japanese eel.