Transcription factor CREB3L1 mediates cAMP and glucocorticoid regulation of arginine vasopressin gene transcription in the rat hypothalamus

Author(s)

Greenwood, Mingkwan ^[1] ; Greenwood, Michael P. ^[1] ; Mecawi, Andre S. ^{[2, 3, 4]} ; Loh, Su Yi ^[3] ; Rodrigues, Jose Antunes ^[2] ; Paton, Julian F. R. ^[5] ; Murphy, David ^{[1, 3]}

Affiliation

^[1] Univ Bristol, Sch Clin Sci, Bristol BS1 3NY, Avon - England

^[2] Univ Sao Paulo, Sch Med Ribeirao Preto, BR-14049 Ribeirao Preto - Brazil

^[3] Univ Malaya, Dept Physiol, Kuala Lumpur 50603 - Malaysia

^[4] Univ Fed Rural Rio de Janeiro, Inst Biol, Dept Physiol Sci, Rio De Janeiro - Brazil

^[5] Univ Bristol, Sch Physiol & Pharmacol, Bristol BS8 1TD, Avon - England

• Document type: Journal article
• Source: MOLECULAR BRAIN; v. 8, OCT 26 2015.
• Web of Science Citations: 6

Abstract

Background: Arginine vasopressin (AVP), a neuropeptide hormone that functions in the regulation of water homeostasis by controlling water re-absorption at kidneys, is synthesised in supraoptic nucleus and paraventricular nucleus of the hypothalamus. An increase in plasma osmolality stimulates secretion of AVP to blood circulation and induces AVP synthesis in these nuclei. Although studies on mechanism of AVP transcriptional regulation in hypothalamus proposed that cAMP and glucocorticoids positively and negatively regulate Avp expression, respectively, the molecular mechanisms have remained elusive. Recently, we identified CREB3L1 (cAMP-responsive element binding protein 3 like 1) as a putative transcription factor of Avp transcription in the rat hypothalamus. However the mechanism of how CREB3L1 is regulated in response of hyperosmotic stress in the neurons of hypothalamus has never been reported. This study aims to investigate effect of previously reported regulators (cAMP and glucocorticoid) of Avp transcription on transcription factor CREB3L1 in order to establish a molecular explanation for cAMP and glucocorticoids effect on AVP expression. Results: The effect of cAMP and glucocorticoid treatment on Creb3l1 was investigated in both AtT20 cells and hypothalamic organotypic cultures. The expression of Creb3l1 was increased in both mRNA and protein level by treatment with forskolin, which raises intracellular cAMP levels. Activation of cAMP by forskolin also increased Avp promoter activity in AtT20 cells and this effect was blunted by shRNA mediated silencing of Creb3l1. The forskolin induced increase in Creb3l1 expression was diminished by combined treatment with dexamethasone, and, in vivo, intraperitoneal dexamethasone injection blunted the increase in Creb3l1 and Avp expression induced by hyperosmotic stress. Conclusion: Here we shows that cAMP and glucocorticoid positively and negatively regulate Creb3l1 expression in the rat hypothalamus, respectively, and regulation of cAMP on AVP expression is mediated through CREB3L1. This data provides the connection between CREB3L1, a newly identified transcription factor of AVP expression, with the previously proposed mechanism of Avp transcription which extends our understanding in transcription regulation of Avp in the hypothalamus. (AU)

• FAPESP's process: 11/52108-4 - Behavioural and neuroendocrine mechanisms regulating hydromineral metabolism: a lifelong perpective
• Grantee: José Antunes Rodrigues
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/09799-1 - Energy balance and body fluid homeostasis control: from cells to the physiological systems
• Grantee: José Antunes Rodrigues
• Support Opportunities: Research Projects - Thematic Grants