Erythropoietin-mediated expression of placenta growth factor is regulated via activation of hypoxia-inducible factor-1α and post-transcriptionally by miR-214 in sickle cell disease.

Placental growth factor (PlGF) plays an important role in various pathological conditions and diseases such as inflammation, cancer, atherosclerosis and sickle cell disease (SCD). Abnormally high PlGF levels in SCD patients are associated with increased inflammation and pulmonary hypertension (PHT) and reactive airway disease; however, the transcriptional and post-transcriptional mechanisms regulating PlGF expression are not well defined. Herein, we show that treatment of human erythroid cells and colony forming units with erythropoietin (EPO) increased PlGF expression. Our studies showed EPO-mediated activation of HIF-1α led to subsequent binding of HIF-1α to hypoxia response elements (HREs) within the PlGF promoter, as demonstrated by luciferase transcription reporter assays and ChIP analysis of the endogenous gene. Additionally, we showed miR-214 post-transcriptionally regulated the expression of PlGF as demonstrated by luciferase reporter assays using wild-type (wt) and mutant PlGF-3'-UTR constructs. Furthermore, synthesis of miR-214, located in an intron of DNM3 (dynamin 3), was transcriptionally regulated by transcription factors, peroxisome proliferator-activated receptor-α (PPARα) and hypoxia-inducible factor-1α (HIF-1α). These results were corroborated in vivo wherein plasma from SCD patients and lung tissues from sickle mice showed an inverse correlation between PlGF and miR-214 levels. Finally, we observed that miR-214 expression could be induced by fenofibrate, a Food and Drug Administration (FDA) approved PPARα agonist, thus revealing a potential therapeutic approach for reduction in PlGF levels by increasing miR-214 transcription. This strategy has potential clinical implications for several pathological conditions including SCD.

Activation of peroxisome proliferator activator receptor delta in mouse impacts lipid composition and placental development at early stage of gestation.

Peroxisome proliferator-activated receptor delta (Ppard) activation has been implicated in regulating a multitude of biological processes in placental development. In this study, we employed the UPLC-ESI-TOFMS approach to investigate the metabolic traits in placenta from GW501516-treated mice at Embryonic Day 10.5. By analyzing the mass spectrum data, ions with the most significant differences between control and GW501516-treated groups were identified. Among these metabolites, the fatty acids, phospholipids, and sterol lipids were dramatically increased. Ingenuity Pathway Analysis (IPA) showed that phosphatidylethanolamine biosynthesis and glycolysis were the top two altered metabolic pathways involved in carbohydrate metabolism, energy production, and lipid metabolism. Subsequent immunoblotting experiments provided evidence for positive correlation of PPARD level and AKT and ERK signaling pathways upon GW501516 treatment. Furthermore, the stimulation of GW501516 increased trophoblast cell fusion gene syncytin-A (Syna), but not syncytin-B (Synb), expression, suggesting a potential role of Ppard activation in promoting cytotrophoblast differentiation. Our results reveal that Ppard activation elicits dramatic changes of the metabolic activities in placenta, which is correlated to AKT and ERK signaling.

The emerging role of estrogen receptor-ß in human reproduction.

Knowledge surrounding estrogen and estrogen receptor biology continues to evolve, and the diversity of their actions and complexity of their mechanisms are becoming increasingly evident. Estrogen receptor (ER) regulation of reproduction is no exception. Although it is well established that estrogen and ERα play key roles in mediating several reproductive biological processes, such as myometrial and endometrial growth, increasing evidence suggests that ERß is also an important factor. ERß is a key mediator in folliculogenesis and may also play a role in stimulating ovulation and regulating aspects of luteinization. ERß is also expressed in higher quantities than ERα in the human myometrium and cervix during pregnancy, and thus it may play a part in the initiation of labor and parturition. Finally, ERß is the sole ER expressed within the endothelium of the endometrium and the fetoplacental vasculature, and studies suggest that its role may contribute to angiogenic and vasomotor changes that play a role in both implantation and regulation of fetoplacental blood flow.

Ontogeny of sulfonylurea-binding regulatory subunits of K(ATP) channels in the pregnant rat myometrium.

ATP-sensitive potassium channels (K(ATP) channels) are composed of sulfonylurea receptors (SURs) and potassium inward rectifiers (Kir(6.x)) that assemble to form a large octameric channel. This study was designed to examine the expression and role of sulfonylurea-binding regulatory subunits 1 (SUR1 (ABCC8)) and 2 (SUR2 (ABCC9)) of the K(ATP) channels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and western blot analyses were performed to detect the presence of SUR1 and SUR2. The SUR1 levels were markedly increased in the early stages of pregnancy. The highest level was detected on day 6 of pregnancy, whereas in the late stages, the levels of SUR1 were significantly decreased. The SUR2 level remained unchanged throughout pregnancy. The SUR non-selective diazoxide and the SUR2-selective pinacidil inhibited oxytocin-induced contractions. Glibenclamide, a K(ATP) channel blocker, antagonized both pinacidil- and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of K(ATP) channel openers. We conclude that both SURs are involved in the K(ATP) channel in the pregnant rat myometrium. It may further be concluded that 'pinacidil-like' K(ATP) channel openers may be of therapeutic relevance as tocolytic agents in the future.