Corticotropin-releasing factor and vasoactive intestinal polypeptide activate gene transcription through the cAMP signaling pathway in a catecholaminergic immortalized neuron.

Corticotropin-releasing factor (CRF) and vasoactive intestinal polypeptide (VIP) are neuropeptides displaying a variety of short-term effects in the nervous system. It is shown here in transfection experiments of an immortalized noradrenergic locus coeruleus-like cell line that both CRF and VIP also trigger a signaling cascade capable of activating gene transcription. To elucidate the signaling pathway leading to transcriptional induction, cells were transfected with an inhibitor for cAMP-dependent protein kinase, targeted to the nucleus via a nuclear-localization signal. Transcriptional induction of a reporter gene by CRF and VIP was blocked in these cells, indicating that the cAMP-dependent protein kinase is required for transducing CRF and VIP generated signals into the nucleus. Additionally, transfection experiments with a reporter gene containing cAMP response elements in its regulatory region demonstrate that CRF and VIP receptor activation induce transcription through this genetic regulatory element. We conclude that long-term effects of CRF and VIP in neurons are likely to be mediated by the transcriptional regulation of CRF and VIP-responsive genes via the cAMP signaling pathway.