Estrogen receptors act via the regulation of transcriptional processes, involving nuclear translocation and binding on specific response elements, thus leading to regulation of target gene expression. However, novel non-transcriptional mechanisms of signal transduction through steroid hormone receptors have been identified. These so-called "non-genomic" effects are independent by gene transcription or protein synthesis and involve steroid-induced modulation of cytoplasmic or of cell membrane-bound regulatory proteins. Relevant biological actions of steroids have been associated with this signaling in different tissues. Ubiquitary regulatory cascades such as mitogen-activated protein kinases (MAPK), the phosphatidylinositol 3-OH kinase (PI3K) and tyrosine kinases are modulated through non-transcriptional mechanisms by steroid hormones. Furthermore, steroid hormone receptors modulation of cell membrane-associated molecules such as ion channels and G-protein-coupled receptors has been shown in diverse tissues. The vascular wall is a site where non-genomic steroid hormones actions are particularly prominent. For instance, estrogens and glucocorticoids trigger rapid vasodilatation due to rapid induction of nitric oxide synthesis in endothelial cells via the estrogen receptor-dependent activation of MAPK and PI3K, leading to relevant pathophysiological consequences, in vitro and in vivo. The growing amount of evidence collected in the last years claims that non-transcriptional signaling mechanisms play a primary role in the generation of the effects of steroids on endothelial cells, which may turn out to be of relevance for clinical purposes.
|Autori:||Simoncini, Tommaso; Mannella, Paolo; Fornari, L; Caruso, A; Varone, G; Genazzani, Andrea|
|Titolo:||Genomic and non-genomic effects of estrogens on endothelial cells|
|Anno del prodotto:||2004|
|Appare nelle tipologie:||1.1 Articolo in rivista|