Molecular mechanisms of stress-induced proenkephalin gene regulation: CREB interacts with the proenkephalin gene in the mouse hypothalamus and is phosphorylated in response to hyperosmolar stress

Abstract

We have established a transgenic model to facilitate the study of stress-induced gene regulation in the hypothalamus. This model, which uses a human proenkephalin-β-galactosidase fusion gene, readily permits anatomic and cellular colocalization of stress-regulated immediate early gene products (e.g. Fos) and other transcription factors [e.g. cAMP response element-binding protein (CREB)] with the product of a potential target gene. Moreover, Fos provides a marker of cellular activation that is independent of the transgene. Hypertonic saline stress induced Fos in almost all cells in the PVN that exhibited basal expression of the proenkephalin transgene; however, all cells in which the transgene was activated by stress also expressed Fos. CREB was found in essentially all neurons. Gel shift analysis with and without antisera to Fos and CREB showed that AP-1 binding activity, containing Fos protein, was induced by hyperosmotic stress. However, Fos was not detected binding to the proenkephalin second messenger-inducible enhancer even in hypothalamic cell extracts from stressed animals. In contrast, CREB formed specific complexes with both the proenkephalin enhancer and a cAMP-and calcium-regulated element (CaRE) within the c-fos gene. Moreover, we found that hypertonic saline induced CREB phosphorylation in cells that express the transgene within the paraventricular nucleus and supraoptic nucleus. These results suggest a model in which proenkephalin gene expression in the paraventricular nucleus is regulated by CREB in response to hypertonic stress.

Phosphorylation of Transcription Factor CREB in Rat Spinal Cord after Formalin-Induced Hyperalgesia: Relationship toc-fosInduction

“…These results are in agreement with previous in vitro observations indicating that CREB phosphorylation is necessary but not sufficient for immediate-early gene activation (Bonni et al, 1995). Finally, CREB-binding sites have been found in several genes involved in pain (Konradi et al, 1993;Borsook et al, 1994;Cole et al, 1995). It will be interesting to determine whether other hyperalgesia-induced genes are also regulated by CREB phosphorylation.…”

“…CREB-binding sites have been found in the promoter regions of immediate-early genes such as c-fos (Sassone-Corsi et al, 1988;Ginty et al, 1992) and Zif /268 (Sakamoto et al, 1991) and genes encoding synapsin I (Sauerwald et al, 1990), somatostatin (Gonzalez and Montminy, 1989), dynorphin (Cole et al, 1995), and enkephalin (Borsook et al, 1994). It has been shown that the phosphorylation of CREB at serine-133 is required for CREB-mediated transcription (Gonzalez and Montminy, 1989;Sheng et al, 1991;Ginty et al, 1994).…”

Dynorphin-containing axons directly innervate noradrenergic neurons in the rat nucleus locus coeruleus

“…In fact, we have previously shown using anterograde and retrograde tracing studies combined with electron microscopic analysis that 1) neurons in the NTS monosynaptically innervate THcontaining dendritic processes in the LC (Van Bockstaele et al, 1999a); 2) axon terminals originating from the BNST synapse with TH-labeled dendrites in the LC (Van Bockstaele et al, 1999b); 3) CNA axon terminals innervate TH-labeled dendrites in LC neurons (Van Bockstaele et al, 1996a); and 4) neurons from the PVN send projections to the LC neurons (Reyes et al, 2005). These nuclei that send efferents to the LC have been implicated in autonomic control (Harper et al, 1984,Reis et al, 1984,Maskati and Zbroayma, 1989,Martin et al, 1991,Ciriello and Janssen, 1993,Roder and Ciriello, 1993,Schlenker et al, 2001) and in stress responses (Borsook et al, 1994,Alheid et al, 1995,Dayas et al, 2004.…”

Transcriptional Control of Gene Expression by cAMP‐Response Element Binding Proteins

“…This pattern of expression suggests that the presence of CREM antagonists may determine region-specific differences in CREB-(or CREMz-) mediated responses to cAMP stimulation. It has been found that a peripheral hyperosmotic challenge results in CREB phosphorylation in the hypothalamic supraoptic and paraventricular nuclei (103). In addition, Mellstrom et al ( 102) found that osmotic stimulation results in the induction of CREMx and CREMP in neurons of the supraoptic nucleus.…”