Neuronal differentiation‐induced change in expression of neurotrophic factor genes in adrenal chromaffin cell line tsAM5D expressing temperature‐sensitive SV40 T‐antigen

We recently established adrenal medullary cell line tsAM5D, immortalized with a temperature-sensitive mutant of the oncogene simian virus 40 large T-antigen. When cultured with basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF), tsAM5D cells proliferated at the permissive temperature (33°C) for the expression of the oncogene and differentiated into neuron-like cells at the nonpermissive temperature (39°C). In the present study, we investigated the gene expression of several neurotrophic factors associated with the neuronal differentiation induced by the temperature shift. Using real-time RT-PCR analysis on bFGF and CNTF-treated cells, we found up-regulated expression of mRNAs for bFGF, leukemia inhibitory factor, transforming growth factor (TGF)-β2, persephin, acidic fibroblast growth factor, neurotrophin-3, preproenkephalin, and TGF-β1 and down-regulated expression of the mRNAs for interleukin-6, neurturin, and CNTF. No apparent differences were observed in the mRNA level of insulin-like growth factor-2, TGF-β3, and neurotrophin-4/5. These results suggest that the regulated expression of neurotrophic factor genes play an important role in the neuronal differentiation of tsAM5D cells.