Membrane‐initiated estradiol signaling increases tyrosine hydroxylase promoter activity with ERα in PC12 cells

This is the authors' abstract. We don't add key points for this paper.

Tyrosine hydroxylase (TH) promoter activity is induced by 17beta-estradiol (E(2)) in PC12 cells expressing estradiol receptor-alpha (ERalpha) requiring a cAMP/calcium response element (CRE/CaRE) at -45. To examine whether membrane-initiated estradiol signaling is underlying this induction, cells co-transfected with TH reporter construct and ERalpha expression vector were exposed to membrane-impermeant estradiol conjugate (beta-estradiol-6-(O-carboxy-methyl) oxime-bovine serum albumin, E(2)BSA). TH promoter activity was elevated by E(2)BSA in dose- and time-dependent manner. E(2)BSA also elicited rapid phosphorylation of CRE binding protein (CREB) and increased CRE-driven promoter activity. Over-expression of dominant negative forms of CREB, with mutations in DNA binding or phosphorylation site, prevented TH promoter response to E(2)BSA. Pre-treatment with protein kinase A (PKA) and MEK inhibitors reduced E(2) dependent phosphorylation of CREB and ERK, and also decreased induction of TH promoter activity by E(2) or E(2)BSA. Blocking S-palmitoylation of ERalpha with C451A mutation and/or pre-treatment with 2-Bromopalmitate did not prevent but instead enhanced E(2) or E(2)BSA-elicited induction of TH promoter activity. These findings reveal, for the first time, that estradiol induction of TH gene transcription with ERalpha in PC12 cells involves membrane-initiated estradiol signaling, rapid activation of dual PKA/MEK signaling pathways, leading to CREB phosphorylation, acting at CRE/CaRE. The data demonstrate possible mechanism whereby estradiol affects catecholaminergic systems in vivo.