Dataset Information

17Beta-estradiol regulation of the mRNA expression of T-type calcium channel subunits: role of estrogen receptor alpha and estrogen receptor beta.

ABSTRACT: Low-voltage-activated (T-type) calcium channels are responsible for burst firing and transmitter release in neurons and are important for exocytosis and hormone secretion in pituitary cells. T-type channels contain an alpha1 subunit, of which there are three subtypes, Cav3.1, -3.2, and -3.3, and each subtype has distinct kinetic characteristics. Although 17beta-estradiol (E2) modulates T-type calcium channel expression and function, little is known about the molecular mechanisms involved. We used real-time PCR quantification of RNA extracted from hypothalamic nuclei and pituitary in vehicle and E2-treated C57BL/6 mice to elucidate E2-mediated regulation of Cav3.1, -3.2, and -3.3 subunits. The three subunits were expressed in both the hypothalamus and the pituitary. E2 treatment increased the mRNA expression of Cav3.1 and -3.2, but not Cav3.3, in the medial preoptic area and the arcuate nucleus. In the pituitary, Cav3.1 was increased with E2 treatment, and Cav3.2 and -3.3 were decreased. To examine whether the classical estrogen receptors (ERs) were involved in the regulation, we used ERalpha- and ERbeta-deficient C57BL/6 mice and explored the effects of E2 on T-type channel subtypes. Indeed, we found that the E2-induced increase in Cav3.1 in the hypothalamus was dependent on ERalpha, whereas the E2 effect on Cav3.2 was dependent on both ERalpha and ERbeta. However, the E2-induced effects in the pituitary were dependent on only the expression of ERalpha. The robust E2 regulation of T-type calcium channels could be an important mechanism by which E2 increases the excitability of hypothalamic neurons and modulates pituitary secretion.

SUBMITTER: Bosch MA

PROVIDER: S-EPMC2821194 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

17Beta-estradiol regulation of the mRNA expression of T-type calcium channel subunits: role of estrogen receptor alpha and estrogen receptor beta.

Bosch Martha A MA Hou Jingwen J Fang Yuan Y Kelly Martin J MJ Rønnekleiv Oline K OK

The Journal of comparative neurology 20090101 3

Low-voltage-activated (T-type) calcium channels are responsible for burst firing and transmitter release in neurons and are important for exocytosis and hormone secretion in pituitary cells. T-type channels contain an alpha1 subunit, of which there are three subtypes, Cav3.1, -3.2, and -3.3, and each subtype has distinct kinetic characteristics. Although 17beta-estradiol (E2) modulates T-type calcium channel expression and function, little is known about the molecular mechanisms involved. We use ...[more]

PMID: 19003958

Similar Datasets

Project description:Estradiol-17beta (E(2)beta) and its metabolites, which are sequentially synthesized by cytochrome P450s and catechol-O-methyltransferase to form 2 and 4-hydroxyestradiol (OHE(2)) and 2- and 4-methoxestradiol (ME(2)), are elevated during pregnancy. We investigated whether cytochrome P450s and catechol-O-methyltransferase are expressed in uterine artery endothelial cells (UAECs) and whether E(2)beta and its metabolites modulate cell proliferation via ER-alpha and/or ER-beta and play roles in physiological uterine angiogenesis during pregnancy. Cultured ovine UAECs from pregnant and nonpregnant ewes were treated with 0.1 to 100.0 nmol/L of E(2)beta, 2-OHE(2), 4-OHE(2), 2-ME(2), and 4-ME(2). ER-alpha or ER-beta specificity was tested using ICI 182 780, ER-alpha-specific 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinyleth oxy)phenol]-1H-pyrazole dihydrochloride, ER-beta-specific 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo [1,5-a]pyrim idin-3-yl]phenol antagonists and their respective agonists ER-alpha-specific 4,4',4"-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol and ER-beta-specific 2,3-bis(4-Hydroxyphenyl)-propionitrile. Angiogenesis was evaluated using 5-bromodeoxyuridine proliferation assay. Using confocal microscopy and Western analyses to determine enzyme location and levels, we observed CYP1A1, CYP1A2, CYP1B1, CYP3A4, and catechol-O-methyltransferase expression in UAECs; however, expressions were similar between nonpregnant UAECs and pregnant UAECs. E(2)beta, 2-OHE(2), 4-OHE(2), and 4-ME(2) treatments concentration-dependently stimulated proliferation in pregnant UAECs but not in nonpregnant UAECs; 2-ME(2) did not stimulate proliferation in either cell type. Proliferative responses of pregnant UAECs to E(2)beta were solely mediated by ER-beta, whereas responses to E(2)beta metabolites were neither ER-alpha nor ER-beta mediated. We demonstrate an important vascular role for E(2)beta, its cytochrome P450- and catechol-O-methyltransferase-derived metabolites, and ER-beta in uterine angiogenesis regulation during pregnancy that may be dysfunctional in preeclampsia and other cardiovascular disorders.

Project description:Estrogen is atheroprotective and a high-affinity ligand for both known estrogen receptors, ERalpha and ERbeta. However, the role of the ERalpha in early-stage atherosclerosis has not been directly investigated and is incompletely understood. ERalpha-deficient (ERalpha-/-) and wild-type (ERalpha+/+) female mice consuming an atherogenic diet were studied concurrent with estrogen replacement to distinguish the actions of 17beta-estradiol (E(2)) from those of ERalpha on the development of early atherosclerotic lesions. Mice were ovariectomized and implanted with subcutaneous slow-release pellets designed to deliver 6 or 8 mug/day of exogenous 17beta-estradiol (E(2)) for a period of up to 4 months. Ovariectomized mice (OVX) with placebo pellets (E(2)-deficient controls) were compared to mice with endogenous E(2) (intact ovaries) and exogenous E(2). Aortas were analyzed for lesion area, number, and distribution. Lipid and hormone levels were also determined. Compared to OVX, early lesion development was significantly (p < 0.001) attenuated by E(2) with 55-64% reduction in lesion area by endogenous E(2) and >90% reduction by exogenous E(2). Compared to OVX, a decline in lesion number (2- to 4-fold) and lesser predilection (~4-fold) of lesion formation in the proximal aorta also occurred with E(2). Lesion size, development, number, and distribution inversely correlated with circulating plasma E(2) levels. However, atheroprotection was independent of ERalpha status, and E(2) athero-protection in both genotypes was not explained by changes in plasma lipid levels (total cholesterol, triglyceride, and high-density lipoprotein cholesterol). The ERalpha is not essential for endogenous/exogenous E(2)-mediated protection against early-stage atherosclerosis. These observations have potentially significant implications for understanding the molecular and cellular mechanisms and timing of estrogen action in different estrogen receptor (ER) deletion murine models of atherosclerosis, as well as implications to human studies of ER polymorphisms and lipid metabolism. Our findings may contribute to future improved clinical decision-making concerning the use of hormone therapy.

Project description:Estrogen can significantly influence CD16 expression and alter monocytic cytokine release upon CD16 receptor activation. However, the function of the estrogen receptor (ER) alpha and beta in this response is unclear. To test whether estrogen binds ERalpha and/or ERbeta to affect CD16 expression, monocytic cells were treated with and without physiological levels of 17beta-estradiol and various doses of the ERalpha and ERbeta antagonist fulvestrant followed by measurement of CD16 transcript levels. To determine how estrogen induced changes in TNF-alpha and IL-1beta release due to CD16 activation we quantitated the amount of cytokines after treatment with estrogen, fulvestrant and antibodies that specifically bind and activate the CD16 receptor. Interaction of ERalpha and the CD16 promoter was then determined by chromatin immunoprecipitation. Furthermore, specific promoter elements utilized by estrogen to control CD16 expression were mutated and expression from a luciferase reporter quantitated after transfection. Using the luciferase reporter construct containing a wild type CD16 promoter, the role of ERalpha and ERbeta in the estrogen response was tested by treating transfected monocytes with an ERalpha specific agonist or an ERbeta specific agonist and measuring expression. Our results show that CD16 transcript levels significantly decreased in monocytic cells due to estrogen and that the observed decrease in message was blocked by the antagonist fulvestrant. Estrogen reduced CD16 expression and decreased TNF-alpha and IL-1beta release upon CD16 activation but the administration of fulvestrant blocked this decrease. ERalpha was found to interact with a region 5' of the CD16 gene in the presence of estrogen, and site-directed mutational analysis of this region indicated the necessity for an estrogen response element in modulating estrogen effects on CD16 expression. Moreover, both an ERalpha and an ERbeta agonist reduced expression of the CD16 reporter construct suggesting both receptors can play a role in CD16 regulation. In conclusion, CD16 expression can be altered by the activity of ERalpha or ERbeta and our results also show that ERalpha can associate with a region within the CD16 promoter that is important in production of transcript.

Dataset Information

17Beta-estradiol regulation of the mRNA expression of T-type calcium channel subunits: role of estrogen receptor alpha and estrogen receptor beta.

Publications

17Beta-estradiol regulation of the mRNA expression of T-type calcium channel subunits: role of estrogen receptor alpha and estrogen receptor beta.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets