Nuclear Sialyl Cholesterol Causes Changes in the Structure of Chromatin and Its Transcription Level Followed by the Promotion of Neuritogenesis

Exogenously added sialyl cholesterol (SC) induced neuritogenesis and accumulated in the nuclear fraction of a mouse neuroblastoma cell line, Neuro2a, as reported elsewhere. To clarify the significance of nuclear SC, we examined the structure of chromatin and its transcriptional level. The chromatin of SC-treated cells exhibits greater circular dichroism amplitude (260-310 nm) than that of nontreated cells. The transcriptional level of chromatin from SC-treated cells was significantly higher than that of nontreated cells. The chromatin structural change has a good correlation to the transcriptional enhancement. On the addition of SC to the chromatin of nontreated cells, the circular dichroism spectra increased in amplitude and the transcriptional level also increased in a concentration-dependent manner. alpha-Amanitin-treated cells did not show SC-dependent neuritogenesis. These results strongly suggest that nuclear SC affects gene expression, which results in promotion of the neuritogenesis of cells.