scholarly journals Nuclear Activation Function 2 Estrogen Receptor α Attenuates Arterial and Renal Alterations Due to Aging and Hypertension in Female Mice

Author(s):  
Emmanuel Guivarc'h ◽  
Julie Favre ◽  
Anne‐Laure Guihot ◽  
Emilie Vessières ◽  
Linda Grimaud ◽  
...  

Background The cardiovascular protective effects of estrogens in premenopausal women depend mainly on estrogen receptor α (ERα). ERα activates nuclear gene transcription regulation and membrane‐initiated signaling. The latter plays a key role in estrogen‐dependent activation of endothelial NO synthase. The goal of the present work was to determine the respective roles of the 2 ERα activities in endothelial function and cardiac and kidney damage in young and old female mice with hypertension, which is a major risk factor in postmenopausal women. Methods and Results Five‐ and 18‐month‐old female mice lacking either ERα (ERα −/− ), the nuclear activating function AF2 of ERα (AF2°), or membrane‐located ERα (C451A) were treated with angiotensin II (0.5 mg/kg per day) for 1 month. Systolic blood pressure, left ventricle weight, vascular reactivity, and kidney function were then assessed. Angiotensin II increased systolic blood pressure, ventricle weight, and vascular contractility in ERα −/− and AF2° mice more than in wild‐type and C451A mice, independent of age. In both the aorta and mesenteric resistance arteries, angiotensin II and aging reduced endothelium‐dependent relaxation in all groups, but this effect was more pronounced in ERα −/− and AF2° than in the wild‐type and C451A mice. Kidney inflammation and oxidative stress, as well as blood urea and creatinine levels, were also more pronounced in old hypertensive ERα −/− and AF2° than in old hypertensive wild‐type and C451A mice. Conclusions The nuclear ERα‐AF2 dependent function attenuates angiotensin II–dependent hypertension and protects target organs in aging mice, whereas membrane ERα signaling does not seem to play a role.

2007 ◽  
Vol 292 (4) ◽  
pp. H1770-H1776 ◽  
Author(s):  
Baojian Xue ◽  
Jaya Pamidimukkala ◽  
Dennis B. Lubahn ◽  
Meredith Hay

It has been shown that the female sex hormones have a protective role in the development of angiotensin II (ANG II)-induced hypertension. The present study tested the hypotheses that 1) the estrogen receptor-α (ERα) is involved in the protective effects of estrogen against ANG II-induced hypertension and 2) central ERs are involved. Blood pressure (BP) was measured in female mice with the use of telemetry implants. ANG II (800 ng·kg−1·min−1) was administered subcutaneously via an osmotic pump. Baseline BP in the intact, ovariectomized (OVX) wild-type (WT) and ERα knockout (ERαKO) mice was similar; however, the increase in BP induced by ANG II was greater in OVX WT (23.0 ± 1.0 mmHg) and ERαKO mice (23.8 ± 2.5 mmHg) than in intact WT mice (10.1 ± 4.5 mmHg). In OVX WT mice, central infusion of 17β-estradiol (E2; 30 μg·kg−1·day−1) attenuated the pressor effect of ANG II (7.0 ± 0.4 mmHg), and this protective effect of E2 was prevented by coadministration of ICI-182,780 (ICI; 1.5 μg·kg−1·day−1, 18.8 ± 1.5 mmHg), a nonselective ER antagonist. Furthermore, central, but not peripheral, infusions of ICI augmented the pressor effects of ANG II in intact WT mice (17.8 ± 4.2 mmHg). In contrast, the pressor effect of ANG II was unchanged in either central E2-treated OVX ERαKO mice (19.0 ± 1.1 mmHg) or central ICI-treated intact ERαKO mice (19.6 ± 1.6 mmHg). Lastly, ganglionic blockade on day 7 after ANG II infusions resulted in a greater reduction in BP in OVX WT, central ER antagonist-treated intact WT, central E2 + ICI-treated OVX WT, ERαKO, and central E2- or ICI-treated ERαKO mice compared with that in intact WT mice given just ANG II. Together, these data indicate that ERα, especially central expression of the ER, mediates the protective effects of estrogen against ANG II-induced hypertension.


2018 ◽  
Vol 314 (2) ◽  
pp. H330-H342 ◽  
Author(s):  
Seong Chul Kim ◽  
Austin C. Boese ◽  
Matthew H. Moore ◽  
Rea M. Cleland ◽  
Lin Chang ◽  
...  

Estrogen has been shown to affect vascular reactivity. Here, we assessed the estrogen receptor-α (ERα) dependency of estrogenic effects on vasorelaxation via a rapid nongenomic pathway in both male and ovary-intact female mice. We compared the effect of a primary estrogen, 17β-estradiol (E2) or 4,4′,4″-(4-propyl-[1H]pyrazole-1,3,5-triyl)tris-phenol (PPT; selective ERα agonist). We found that E2 and PPT induced greater aortic relaxation in female mice than in male mice, indicating ERα mediation, which was further validated by using ERα antagonism. Treatment with 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride (MPP dihydrochloride; ERα antagonist) attenuated PPT-mediated vessel relaxation in both sexes. ERα-mediated vessel relaxation was further validated by the absence of significant PPT-mediated relaxation in aortas isolated from ERα knockout mice. Treatment with a specific ERK inhibitor, PD-98059, reduced E2-induced vessel relaxation in both sexes but to a lesser extent in female mice. Furthermore, PD-98059 prevented PPT-induced vessel relaxation in both sexes. Both E2 and PPT treatment activated ERK as early as 5–10 min, which was attenuated by PD-98059 in aortic tissue, cultured primary vascular smooth muscle cells (VSMCs), and endothelial cells (ECs). Aortic rings denuded of endothelium showed no differences in vessel relaxation after E2 or PPT treatment, implicating a role of ECs in the observed sex differences. Here, our results are unique to show estrogen-stimulated rapid ERα signaling mediated by ERK activation in aortic tissue, as well as VSMCs and ECs in vitro, in regulating vascular function by using side-by-side comparisons in male and ovary-intact female mice in response to E2 or PPT. NEW & NOTEWORTHY Here, we assessed the estrogen receptor-α dependency of estrogenic effects in vasorelaxation of both male and ovary-intact female mice by performing side-by-side comparisons. Also, we describe the connection between estrogen-stimulated rapid estrogen receptor-α signaling and downstream ERK activation in regulating vascular function in male and ovary-intact female mice.


1997 ◽  
Vol 272 (2) ◽  
pp. H648-H656 ◽  
Author(s):  
B. Csiky ◽  
G. Simon

We tested, in the early stage of angiotensin II (ANG II)-induced hypertension, whether sympathectomy prevented the autopotentiation of vasoconstrictor responses by ANG II and, in the chronic, established phase of hypertension, whether the antihypertensive effect of sympathectomy, if any, was related to the prevention of structural vascular changes. Neonatally and sham-sympathectomized male Sprague-Dawley rats received 100 or 200 ng x kg(-1) x min(-1) ANG II intraperitoneally for 7-10 days or 200 ng x kg(-1) x min(-1) ANG II subcutaneously for 4 wk. Sham-treated sympathectomized and sham-sympathectomized rats were controls. Vasoconstrictor responses to ANG II, norepinephrine (NE), arginine vasopressin, and periarterial nerve stimulation were measured in the mesentery of rats, and thereafter, in the chronically treated rats, mesenteric resistance arteries were fixed in situ for morphometric measurements. In ANG II-treated sham-sympathectomized rats: 1) tail systolic blood pressure was unchanged after 7-10 days and increased by 23 mmHg at 4 wk (P < 0.001); 2) vasoconstrictor responses were selectively increased to ANG II (autopotentiation; P = 0.026) and nerve stimulation (P = 0.031) at 7-10 days and nonselectively increased to all stimuli at 4 wk (P < 0.05 to P < 0.01); and 3) after 4 wk, the wall-to-lumen ratio of resistance arteries was increased (P < 0.02). In ANG II-treated sympathectomized rats, there were no changes in systolic blood pressure or vasoconstrictor responses at either 7-10 days or 4 wk, but structural vascular changes developed to the same extent as in sham-sympathectomized ANG II-treated rats. Autopotentiation of vasoconstrictor responses appears to be due to an interaction between ANG II and the sympathetic nervous system, because it is prevented by sympathectomy. The dissociation of function and structure in the chronic stage of ANG II administration to sympathectomized rats suggests that structural vascular changes by themselves are insufficient to cause hypertension, but increased vascular reactivity or vasoconstrictor input is also needed.


Endocrinology ◽  
2000 ◽  
Vol 141 (10) ◽  
pp. 3792-3798 ◽  
Author(s):  
Cheryl S. Rosenfeld ◽  
Paul S. Cooke ◽  
Thomas H. Welsh ◽  
Gretchen Simmer ◽  
Martha G. Hufford ◽  
...  

Biochemistry ◽  
2004 ◽  
Vol 43 (21) ◽  
pp. 6698-6708 ◽  
Author(s):  
Brian J. Philips ◽  
Pete J. Ansell ◽  
Leslie G. Newton ◽  
Nobuhiro Harada ◽  
Shin-Ichiro Honda ◽  
...  

2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Josh Uhlorn ◽  
Nathaniel A. Husband ◽  
Melissa J. Romero‐Aleshire ◽  
Dennis P. Pollow ◽  
Jennifer L. Uhrlaub ◽  
...  

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
A. Phillip Owens ◽  
Deborah A Howatt ◽  
Alan Daugherty

Objective: We previously demonstrated that angiotensin II (AngII) infusion into myeloid differentiation factor 88 deficient mice (MyD88−/−) resulted in a profound reduction of atherosclerosis and abdominal aortic aneurysms (AAAs) in apoE−/− mice. Furthermore, AngII directly regulated toll-like receptor (TLR) mRNA in cell types associated with these diseases. The objective of this study was to determine the specific TLR responsible for the MyD88 mediated reduction in vascular pathology. Methods and Results: MyD88 mice were bred onto an LDLr−/− background. Deficiency in this hyperlipidemic strain caused similar decreases in AngII-induced atherosclerosis and aneurysm to those we previously noted in apoE−/− mice. Male TLR4+/+ (n = 14) or −/− (n = 19), on an LDLr−/− background, were fed a fat-enriched diet (21% milk fat, 0.15% cholesterol) and infused with AngII (1,000ng/kg/min) for 28 days. TLR4−/− mice had significantly attenuated systolic blood pressure from TLR4+/+ mice both prior to and during AngII infusion (P < .01). However, AngII did increase systolic blood pressure similarly in both groups (+/+: pre-infusion 142 ± 2, post-infusion 169 ± 3 mmHg; −/−: pre-infusion 130 ± 1, post-infusion 158 ± 3 mmHg; P < .001). Neither TLR4 genotype nor AngII infusions had significantly different effects on total plasma cholesterol concentrations or lipoprotein-cholesterol distributions. TLR4 deficiency dramatically decreased AngII-induced atherosclerotic lesion areas in both the aortic arch (50% decrease, P < .004), and thoracic aorta (66% decrease, P < .001). TLR4 deficiency decreased the diameter of the suprarenal abdominal aortic region from 2.31 ± 0.3 to 1.2 ± 0.06 mm (P < 0.001) and the incidence of AAAs from 93% to 26% (P < 0.001), versus control animals. Conversely, TLR2 deficiency reduced AngII-induced atherosclerosis in LDLr−/− mice, but had no significant effect on AAA formation. Conclusion: TLR4 deficiency attenuated both AngII-induced atherosclerosis and AAAs, in LDLr−/− mice, in a manner similar to the effects of MyD88 deficiency. TLR2 deficiency decreased AngII-induced atherosclerosis, but had no effect on AAAs. These data are consistent with TLR4 being the major receptor for MyD88-induced effects on AngII-induced AAAs. This research has received full or partial funding support from the American Heart Association, AHA Great Rivers Affiliate (Delaware, Kentucky, Ohio, Pennsylvania & West Virginia).


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