Calcium/calmodulin kinase IV pathway is involved in the transcriptional regulation of the corticotropin-releasing hormone gene promoter in neuronal cells

Abstract

Although corticotropin-releasing hormone (CRH) plays a pivotal role in the regulation of the hypothalamo-pituitary-adrenal axis, the mechanism of CRH gene expression in the neuronal cell is not completely understood. In this study, we examined the transcriptional regulation of human CRH gene 58-promoter, using a human BE(2)C neuroblastoma cell line expressing intrinsic CRH. In particular, we focused on the involvement of calmodulin kinases (CaMKs), which are known to play an important role in excitation-induced gene expression through the rise in intracellular calcium in the central nervous system. RT-PCR analysis confirmed the expression of CaMK as well as CRH mRNA in BE(2)C cells. When we introduced <1·1 kb of the 58-promoter region of the human CRH fused with luciferase reporter gene into the cells, a substantial transcriptional activity was observed, and this was further increased by the activation of the cAMP/PKA pathway. We then examined the effect of activation of CaMKs by introducing the expression vectors of each kinase, revealing a potent stimulatory effect of CaMKIV, but no effect of CaMKII. Depolarization of the cells caused an increase in CRH promoter activity, which was completely abolished by the treatment with the CaMK antagonist K252a. Interestingly, KCREB, a dominant negative form of CREB, antagonized the effect of the CaMKIV-mediated effect. Altogether, we conclude that not only the cAMP/PKA but also the calcium/CaMKIV signaling pathway is involved in the regulation of CRH gene expression. Furthermore, CREB is thought to be involved in CaMK-as well as cAMP/PKA-mediated CRH gene expression. Since the CRH gene is expressed in the neuronal cells of the hypothalamus, the calcium/CaMKIV signaling pathway may play an important role in the excitation-mediated regulation of CRH synthesis.

Antipsychotic Drugs Inhibit the Human Corticotropin-Releasing-Hormone Gene Promoter Activity in Neuro-2A Cells—an Involvement of Protein Kinases

“…Inhibition of CaMK and MAPK decreased, while inhibition of PKB enhanced the basal activity of the investigated gene in Neuro-2A cells. Similarly, Yamamori et al (2004) found that activation of CaMK exerted a potent stimulatory effect on CRH gene promoter activity in human neuroblastoma cell line, but the effect of MAPK and PKB activation of CRH gene activity has not been studied yet.…”

Angiotensin II Type 1 Receptor Signaling Regulates Feeding Behavior through Anorexigenic Corticotropin-releasing Hormone in Hypothalamus

“…7A). Deletion of the cAMP-responsive element (CRE) located between Ϫ330 and Ϫ220 of the Crh promoter (14,25) significantly reduced the fold activation by Ang II stimulation (Fig. 7B), and co-transfection of an expression vector for DN-CREB diminished Ang II-induced fold activation of Ϫ907 Crh-Luc in a dose-dependent manner (Fig.…”

“…Experiments were repeated at least three times in triplicate, and representative data are shown. The Crh luciferase reporter plasmids and the expression vector for dominant-negative form of CRE-binding protein (DN-CREB) (14) were a generous gift from Dr. Y. Iwasaki (Kochi University).…”

Different effects of corticotropin-releasing factor and urocortin 2 on apoptosis of prostate cancer cells in vitro

“…Tsatsanis et al (2005) suggested that Ucn and Ucn2 induced macrophage apoptosis via CRFR2, in which the pro-apoptosis pathway activated by the proapoptotic Bax and Bad proteins was involved. Cyclic AMP response element-binding (CREB) protein, an activated transcription factor of Bcl-2, is reported to be phosphorylated by CRF family peptides (Yamamori et al 2004). These results highly suggest that CRF family might influence prostatic tumor growth by affecting Bcl-2/Bax ratio.…”