425 research outputs found
The RNA-binding protein, ZFP36L2, influences ovulation and oocyte maturation
ZFP36L2 protein destabilizes AU-rich element-containing transcripts and has been implicated in female fertility. In the C57BL/6NTac mouse, a mutation in Zfp36l2 that results in the decreased expression of a form of ZFP36L2 in which the 29 N-terminal amino acid residues have been deleted, ÎN-ZFP36L2, leads to fertilized eggs that arrest at the two-cell stage. Interestingly, homozygous ÎN-Zfp36l2 females in the C57BL/6NTac strain release 40% fewer eggs than the WT littermates (Ramos et al., 2004), suggesting an additional defect in ovulation and/or oocyte maturation. Curiously, the same ÎN-Zfp36l2 mutation into the SV129 strain resulted in anovulation, prompting us to investigate a potential problem in ovulation and oocyte maturation. Remarkably, only 20% of ÎN-Zfp36l2 oocytes in the 129S6/SvEvTac strain matured ex vivo, suggesting a defect on the oocyte meiotic maturation process. Treatment of ÎN-Zfp36l2 oocytes with a PKA inhibitor partially rescued the meiotic arrested oocytes. Furthermore, cAMP levels were increased in ÎN-Zfp36l2 oocytes, linking the cAMP/PKA pathway and ÎN-Zfp36l2 with meiotic arrest. Since ovulation and oocyte maturation are both triggered by LHR signaling, the downstream pathway was investigated. Adenylyl cyclase activity was increased in ÎN-Zfp36l2 ovaries only upon LH stimulation. Moreover, we discovered that ZFP36L2 interacts with the 3âČUTR of LHR mRNA and that decreased expression levels of Zfp36l2 correlates with higher levels of LHR mRNA in synchronized ovaries. Furthermore, overexpression of ZFP36L2 decreases the endogenous expression of LHR mRNA in a cell line. Therefore, we propose that lack of the physiological down regulation of LHR mRNA levels by ZFP36L2 in the ovaries is associated with anovulation and oocyte meiotic arrest.Fil: Ball, Christopher B.. University of North Carolina; Estados UnidosFil: Rodriguez, Karina F.. National Institutes of Health; Estados UnidosFil: Stumpo, Deborah J.. National Institutes of Health; Estados UnidosFil: Ribeiro Neto, Fernando. National Institutes of Health; Estados UnidosFil: Korach, Kenneth S.. National Institutes of Health; Estados UnidosFil: Blackshear, Perry J.. University of Duke; Estados Unidos. National Institutes of Health; Estados UnidosFil: Birnbaumer, Lutz. National Institutes of Health; Estados Unidos. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Ramos, Silvia B. V.. University of North Carolina; Estados Unido
Long-term follow-up after cardiac resynchronization therapy-optimization in a real-world setting: A single-center cohort study
Background: Suboptimal device programming is among the reasons for reduced response to cardiac resynchronization therapy (CRT). However, whether systematic optimization is beneficial remains unclear, particularly late after CRT implantation. The aim of this single-center cohort study was to assess the effect of systematic atrioventricular delay (AVD) optimization on echocardiographic and device parameters.Methods: Patients undergoing CRT optimization at the University Hospital Zurich between March 2011 and January 2013, for whom a follow-up was available, were included. AVD optimization was based on 12-lead electrocardiography (ECG) and echocardiographic left ventricular inflow characteristics. Parameters were assessed at the time of CRT optimization and follow-up, and were compared between patients with AVD optimization (intervention group) and those for whom no AVD optimization was deemed necessary (control group).Results: Eighty-one patients with a mean age of 64 ± 11 years were included in the analysis. In 73% of patients, AVD was deemed suboptimal and was changed accordingly. After a median follow-up time of 10.4 (IQR 6.2 to 13.2) months, the proportion of patients with sufficient biventricular pacing (> 97% pacing) was greater in the intervention group (78%) compared to controls (50%). Furthermore, AVD adaptation was associated with an improvement in interventricular mechanical delay (decrease of 6.6 ± 26.2 ms vs. increase of 4.3 ± 17.7 ms, p = 0.034) and intraventricular septal-to-lateral delay (decrease of 0.9 ± 48.1 ms vs. increase of 15.9 ± 15.7 ms, p = 0.038), as assessed by tissue Doppler imaging. Accordingly, a reduction was observed in mitral regurgitation along with a trend towards reduced left ventricular volumes.Conclusions: In this âreal-worldâ setting systematic AVD optimization was associated with beneficial effects regarding biventricular pacing and left ventricular remodeling. These data show that AVD optimization may be advantageous in selected CRT patients
Estrogen induces estrogen receptor alpha-dependent cAMP response element-binding protein phosphorylation via mitogen activated protein kinase pathway in basal forebrain cholinergic neurons in vivo
In addition to classical genomic mechanisms, estrogen also exerts
nonclassical effects via a signal transduction system on neurons. To
study whether estrogen has a nonclassical effect on basal forebrain
cholinergic system, we measured the intensity of cAMP response
element-binding protein (CREB) phosphorylation (pCREB) in cholinergic
neurons after administration of 17 beta-estradiol to ovariectomized
(OVX) mice. A significant time-dependent increase in the number of
pCREB-positive cholinergic cells was detected after estrogen
administration in the medial septum-diagonal band (MS-DB) and the
substantia innominata ( SI). The increase was first observed 15 min
after estrogen administration. The role of classical estrogen receptors
(ERs) was evaluated using ER knock-out mice in vivo. The
estrogen-induced CREB phosphorylation in cholinergic neurons was
present in ER beta knock-out mice but completely absent in ER beta
knock-out mice in MS-DB and SI. A series of in vitro studies
demonstrated that estrogen acted directly on cholinergic neurons.
Selective blockade of the mitogen activated protein kinase (MAPK)
pathway in vivo completely prevented estrogen-induced CREB
phosphorylation in cholinergic neurons in MS-DB and SI. In contrast,
blockade of protein kinase A (PKA) was effective only in SI. Finally,
studies in intact female mice revealed levels of CREB phosphorylation
within cholinergic neurons that were similar to those of
estrogen-treated OVX mice. These observations demonstrate an ER
alpha-mediated nonclassical effect of estrogen on the cholinergic
neurons and that these actions are present under physiological
conditions. They also reveal the role of MAPK and PKA-MAPK pathway
activation in nonclassical estrogen signaling in the basal forebrain
cholinergic neurons in vivo
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