scholarly journals Functional Modification of Pituitary Somatotropes in the Aromatase Knockout Mouse and the Effect of Estrogen Replacement

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 604-612 ◽  
Author(s):  
Ming Yan ◽  
Margaret E. E. Jones ◽  
Maria Hernandez ◽  
Dongling Liu ◽  
Evan R. Simpson ◽  
...  

Abstract Available data on the influence of estradiol (E2) on GH levels remains controversial. A factor contributing to this uncertainty is a lack of knowledge of both E2 action on somatotropes as well as the molecular mechanisms involved. In this study we investigated gene expression implicated in GH secretion in somatotropes derived from female aromatase knockout (ArKO) mice. In these mice E2 production is blocked due to disruption of the Cyp19 gene encoding aromatase, the enzyme responsible for estrogen biosynthesis. The effect of E2 replacement was also studied by in vivo treatment of mice with E2 for 3 wk. It was demonstrated that somatotropes from ArKO mice had a low expression of GH, GH secretagogue receptor, GHRH receptor (GHRH-R), and pituitary-specific transcription factor (Pit-1). On the other hand, the somatotropes exhibited elevated expression of somatostatin receptors (sst1–5). Overall, these effects resulted in a reduction in GH secretion. E2 replacement increased GHRH-R, Pit-1, and GH mRNA levels to 185%, 193%, and 157% and reduced the levels of sst1, sst2, sst4, and sst5 mRNA expression in ArKO mice, respectively. E2 replacement did not affect the levels of pituitary estrogen (α and β) and androgen receptor mRNA expression. It is concluded that the expression of important genes involved in GH synthesis in somatotropes of the female ArKO mouse are functionally down-regulated, and such a down-regulation is reversed to normal levels by E2 replacement. The levels of GH secretagogue receptor, GHRH-R, and Pit-1 mRNA expression were also reduced, and sst1 and sst3 mRNA expression enhanced in aging ArKO and wild-type mice, resulting in a decrease in GH mRNA expression. It is suggested that aging is another important impact factor for the pituitary expression and regulation of GH mRNA in female mice.

2008 ◽  
Vol 14 (5) ◽  
pp. 622-630 ◽  
Author(s):  
M Krakauer ◽  
P Sorensen ◽  
M Khademi ◽  
T Olsson ◽  
F Sellebjerg

Background Interferon (IFN)-β therapy in multiple sclerosis (MS) has been suggested to promote a deviation from T lymphocyte production of pathogenic Th1 cytokines to less detrimental Th2 cytokines, but this is still controversial. We studied patterns of in vivo blood mononuclear cell (MNC) and whole blood cytokine and transcription factor mRNA expression before and during IFN-β therapy in MS. Methods Twenty patients with relapsing–remitting MS were sampled before and after 3 months of treatment with IFN-β along with 15 healthy volunteers. An additional 39 patients and 50 healthy volunteers served to confirm initial findings. mRNA was analyzed by real-time reverse transcriptase polymerase chain reaction (PCR). Results We found elevated expression of interleukin (IL)-23 and IL-10 in untreated MS patients. IFN-β therapy increased IL-10 and decreased IL-23 expression independently of any Th1 or Th2 cytokines. The largest changes in cytokine mRNA levels occurred early (~9–12 h) after an IFN-β injection. Conclusion We found no evidence of a Th1- or Th2-mRNA-promoting effect of IFN-β therapy. The therapeutic effect of IFN-β is more likely attributable to the induction of the regulatory cytokine IL-10. The elevated IL-23 mRNA levels in MS patients are noteworthy in view of the newly discovered IL-23-driven Th17 T-cell subset, which is crucial in animal models of MS. Since IFN-β therapy resulted in decreased IL-23 mRNA levels, the Th17 axis could be another target of IFN-β therapy.


Endocrinology ◽  
2014 ◽  
Vol 155 (4) ◽  
pp. 1407-1417 ◽  
Author(s):  
Raúl M. Luque ◽  
José Córdoba-Chacón ◽  
Alejandro Ibáñez-Costa ◽  
Iacopo Gesmundo ◽  
Cristina Grande ◽  
...  

Obestatin is a 23-amino-acid amidated peptide that is encoded by the ghrelin gene. Previous studies have shown obestatin can modulate the hypothalamic neuronal circuitry that regulates pituitary function, perhaps by modulating the actions of ghrelin. However, the direct actions of obestatin on pituitary function remain controversial. Here, primary pituitary cell cultures from a nonhuman primate (baboon) and mice were used to test the effects of obestatin on pituitary hormone expression and secretion. In pituitary cultures from both species, obestatin had no effect on prolactin, LH, FSH, or TSH expression/release. Conversely, obestatin stimulated proopiomelanocortin expression and ACTH release and inhibited GH expression/release in vitro, actions that were also observed in vivo in mice treated with obestatin. In vitro, obestatin inhibited the stimulatory actions of ghrelin on GH but not ACTH release. The inhibitory effect of obestatin on somatotrope function was associated with an overall reduction in pituitary transcription factor-1 and GHRH receptor mRNA levels in vitro and in vivo as well as a reduction in hypothalamic GHRH and ghrelin expression in vivo. The stimulatory effect of obestatin on ACTH was associated with an increase in pituitary CRF receptors. Obestatin also reduced the expression of pituitary somatostatin receptors (sst1/sst2), which could serve to modify its impact on hormone secretion. The in vitro actions of obestatin on both GH and ACTH release required the adenylyl cyclase and MAPK routes. Taken together, our results provide evidence that obestatin can act directly at the pituitary to control somatotrope and corticotrope function, and these effects are conserved across species.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hai-Jun Gao ◽  
Xu-Dong Sun ◽  
Yan-Ping Luo ◽  
Hua-Sheng Pang ◽  
Xing-Ming Ma ◽  
...  

Abstract Background Echinococcosis, which is caused by the larvae of cestodes of the genus Echinococcus, is a parasitic zoonosis that poses a serious threat to the health of humans and animals globally. Albendazole is the drug of choice for the treatment of echinococcosis, but it is difficult to meet clinical goals with this chemotherapy due to its low cure rate and associated side effects after its long-term use. Hence, novel anti-parasitic targets and effective treatment alternatives are urgently needed. A previous study showed that verapamil (Vepm) can suppress the growth of Echinococcus granulosus larvae; however, the mechanism of this effect remains unclear. The aim of the present study was to gain insight into the anti-echinococcal effect of Vepm on Echinococcus with a particular focus on the regulatory effect of Vepm on calcium/calmodulin-dependent protein kinase II (Ca2+/CaM-CaMKII) in infected mice. Methods The anti-echinococcal effects of Vepm on Echinococcus granulosus protoscoleces (PSC) in vitro and Echinococcus multilocularis metacestodes in infected mice were assessed. The morphological alterations in Echinococcus spp. induced by Vepm were observed by scanning electron microscopy (SEM), and the changes in calcium content in both the parasite and mouse serum and liver were measured by SEM-energy dispersive spectrometry, inductively coupled plasma mass spectrometry and alizarin red staining. Additionally, the changes in the protein and mRNA levels of CaM and CaMKII in infected mice, and in the mRNA levels of CaMKII in E. granulosus PSC, were evaluated after treatment with Vepm by immunohistochemistry and/or real-time quantitative polymerase chain reaction. Results In vitro, E. granulosus PSC could be killed by Vepm at a concentration of 0.5 μg/ml or higher within 8 days. Under these conditions, the ultrastructure of PSC was damaged, and this damage was accompanied by obvious calcium loss and downregulation of CaMKII mRNA expression. In vivo, the weight and the calcium content of E. multilocularis metacestodes from mice were reduced after treatment with 40 mg/kg Vepm, and an elevation of the calcium content in the sera and livers of infected mice was observed. In addition, downregulation of CaM and CaMKII protein and mRNA expression in the livers of mice infected with E. multilocularis metacestodes was found after treatment with Vepm. Conclusions Vepm exerted a parasiticidal effect against Echinococcus both in vitro and in vivo through downregulating the expression of Ca2+/CaM-CaMKII, which was over-activated by parasitic infection. The results suggest that Ca2+/CaM-CaMKII may be a novel drug target, and that Vepm is a potential anti-echinococcal drug for the future control of echinococcosis.


2012 ◽  
Vol 303 (10) ◽  
pp. L852-L860 ◽  
Author(s):  
S. Yoshida ◽  
N. Minematsu ◽  
S. Chubachi ◽  
H. Nakamura ◽  
M. Miyazaki ◽  
...  

Efferocytosis is believed to be a key regulator for lung inflammation in chronic obstructive pulmonary disease. In this study we pharmacologically inhibited efferocytosis with annexin V and attempted to determine its impact on the progression of pulmonary emphysema in mouse. We first demonstrated in vitro and in vivo efferocytosis experiments using annexin V, an inhibitor for phosphatidylserine-mediated efferocytosis. We then inhibited efferocytosis in porcine pancreatic elastase (PPE)-treated mice. PPE-treated mice were instilled annexin V intranasally starting from day 8 until day 20. Mean linear intercept (Lm) was measured, and cell apoptosis was assessed in lung specimen obtained on day 21. Cell profile, apoptosis, and mRNA expression of matrix metalloproteinases (MMPs) and growth factors were evaluated in bronchoalveolar lavage (BAL) cells on day 15. Annexin V attenuated macrophage efferocytosis both in vitro and in vivo. PPE-treated mice had a significant higher Lm, and annexin V further increased that by 32%. More number of macrophages was found in BAL fluid in this group. Interestingly, cell apoptosis was not increased by annexin V treatment both in lung specimens and BAL fluid, but macrophages from mice treated with both PPE and annexin V expressed higher MMP-2 mRNA levels and had a trend for higher MMP-12 mRNA expression. mRNA expression of keratinocyte growth factor tended to be downregulated. We showed that inhibited efferocytosis with annexin V worsened elastase-induced pulmonary emphysema in mice, which was, at least partly, attributed to a lack of phenotypic change in macrophages toward anti-inflammatory one.


2007 ◽  
Vol 292 (1) ◽  
pp. R637-R643 ◽  
Author(s):  
Willis K. Samson ◽  
Meghan M. White ◽  
Christopher Price ◽  
Alastair V. Ferguson

Derived from the same prohormone, obestatin has been reported to exert effects on food intake that oppose those of ghrelin. The obestatin receptor GPR39 is present in brain and pituitary gland. Since the gene encoding those two peptides is expressed also in those tissues, we examined further the possible actions of obestatin in vivo and in vitro. Intracerebroventricular administration of obestatin inhibited water drinking in ad libitum-fed and -watered rats, and in food-and water-deprived animals. The effects on water drinking preceded and were more pronounced than any effect on food intake, and did not appear to be the result of altered locomotor/behavioral activity. In addition, obestatin inhibited ANG II-induced water drinking in animals provided free access to water and food. Current-clamp recordings from cultured, subfornical organ neurons revealed significant effects of the peptide on membrane potential, suggesting this as a potential site of action. In pituitary cell cultures, log molar concentrations of obestatin ranging from 1.0 pM to 100 nM failed to alter basal growth hormone (GH) secretion. In addition, 100 nM obestatin failed to interfere with the stimulation of GH secretion by GH-releasing hormone or ghrelin and did not alter the inhibition by somatostatin in vitro. We conclude that obestatin does not act in pituitary gland to regulate GH secretion but may act in brain to alter thirst mechanisms. Importantly, in rats the effects of obestatin on food intake may be secondary to an action of the peptide to inhibit water drinking.


2001 ◽  
Vol 280 (3) ◽  
pp. L390-L399 ◽  
Author(s):  
Jane K. Mellott ◽  
Harry S. Nick ◽  
Michael F. Waters ◽  
Timothy R. Billiar ◽  
David A. Geller ◽  
...  

Transcription of the human inducible nitric oxide synthase ( iNOS) gene is regulated by inflammatory cytokines in a tissue-specific manner. To determine whether differences in cytokine-induced mRNA levels between pulmonary epithelial cells (A549) and hepatic biliary epithelial cells (AKN-1) result from different protein or DNA regulatory mechanisms, we identified cytokine-induced changes in DNase I-hypersensitive (HS) sites in 13 kb of the iNOS 5′-flanking region. Data showed both constitutive and inducible HS sites in an overlapping yet cell type-specific pattern. Using in vivo footprinting and ligation-mediated PCR to detect potential DNA or protein interactions, we examined one promoter region near −5 kb containing both constitutive and cytokine-induced HS sites. In both cell types, three in vivo footprints were present in both control and cytokine-treated cells, and each mapped within a constitutive HS site. The remaining footprint appeared only in response to cytokine treatment and mapped to an inducible HS site. These studies, performed on chromatin in situ, identify a portion of the molecular mechanisms regulating transcription of the human iNOS gene in both lung- and liver-derived epithelial cells.


2015 ◽  
Vol 27 (1) ◽  
pp. 200
Author(s):  
J.-S. Lee ◽  
E.-B. Jeung

2-Methoxyestradiol (2-ME), an endogenous metabolite of 17β-oestradiol, interacts with oestrogen receptors and microtubules and has a low affinity for oestrogen receptors (ER). It has attracted considerable interest due to its potential anti-cancer therapeutic effects. 2-ME is also recognised for its unique and profound actions on various tumour cell lines and cancer independent of the hormone receptor status. Regardless of differences in function, 2-ME has an affinity for ER, however, the exact mechanisms of 2-ME action via the ER are not fully understood. In the current study, we examined the estrogenic effect of 2-ME on mRNA levels of CaBP-9k, ER, and progesterone receptor (PR) in the absence or presence of the 17β-oestradiol (E2) and progesterone (P4) in both in vivo and in vitro models by real-time RT–PCR. In vitro, cells (n = 3 per group) were exposed to a single dose of E2 (10–9 M), P4 (10–6 M), 2-ME (10–8 M, 10–7 M, 10–6 M). The mechanism of CaBP-9k induction by these chemicals pre-treated with 10–7 M ICI 182, 780 and 10–6 M RU 486 for 30 min before exposure to E2 and 2-ME were analysed. In vivo, 35 female ICR mice (PND 14 days) were divided into 7 groups (n = 5 per group), and each group was administered subcutaneously with 24% DMSO, 38% ethanol, and 38% sterile saline as a vehicle, E2 [40 μg kg–1 of body weight (BW)] a physiological dose level), 2-ME (4, 40, and 80 mg kg–1 of BW) for 3 days. The mice were killed 24 h after the final injection. To investigate the effect of antagonism, 10 mice were injected SC with ICI 182 780 (10 mg kg–1 of BW) and RU 486 (10 mg kg–1 of BW) at 30 min before injection with 2-ME (40 mg kg–1 of BW) for 3 days and killed 24 h after the final injection. Results are presented as mean ± s.e.m.; P-values were calculated using one-way ANOVA. In GH3 cells, the mRNA level of CaBP-9k was induced in the E2 (10–9 M) treatment group, and expression of CaBP-9k was also up-regulated in the 2-ME (10–7 M)-treated group. Uterine lactoferrin (Ltf) mRNA expression was also increased in the 2-ME (40 mg kg–1 of BW) group, similar to the response with E2 (40 μg kg–1 of BW) in mice. As a blocker for ER and PR activity, ICI 182 780 and RU 486 reversed the E2 or 2-ME mediated increase of CaBP-9k and Ltf mRNA expression. We found that 2-ME significantly increased the levels of ERa and PR transcripts. In parallel with in vitro results, the mRNA levels of ERa and PR were induced by treatment with E2 and 2-ME. Taken together, our findings demonstrated that expression of estrogenic markers, CaBP-9k and Ltf, was regulated by 2-ME in both in vitro and in vivo, which may increase their estrogenic activities in female during the cycle through ER and/or PR-mediated pathway.


2007 ◽  
Vol 18 (8) ◽  
pp. 2864-2872 ◽  
Author(s):  
Kelly J. Perkins ◽  
Utpal Basu ◽  
Murat T. Budak ◽  
Caroline Ketterer ◽  
Santhosh M. Baby ◽  
...  

Utrophin is the autosomal homologue of dystrophin, the protein product of the Duchenne's muscular dystrophy (DMD) locus. Utrophin expression is temporally and spatially regulated being developmentally down-regulated perinatally and enriched at neuromuscular junctions (NMJs) in adult muscle. Synaptic localization of utrophin occurs in part by heregulin-mediated extracellular signal-regulated kinase (ERK)-phosphorylation, leading to binding of GABPα/β to the N-box/EBS and activation of the major utrophin promoter-A expressed in myofibers. However, molecular mechanisms contributing to concurrent extrasynaptic silencing that must occur to achieve NMJ localization are unknown. We demonstrate that the Ets-2 repressor factor (ERF) represses extrasynaptic utrophin-A in muscle. Gel shift and chromatin immunoprecipitation studies demonstrated physical association of ERF with the utrophin-A promoter N-box/EBS site. ERF overexpression repressed utrophin-A promoter activity; conversely, small interfering RNA-mediated ERF knockdown enhanced promoter activity as well as endogenous utrophin mRNA levels in cultured muscle cells in vitro. Laser-capture microscopy of tibialis anterior NMJ and extrasynaptic transcriptomes and gene transfer studies provide spatial and direct evidence, respectively, for ERF-mediated utrophin repression in vivo. Together, these studies suggest “repressing repressors” as a potential strategy for achieving utrophin up-regulation in DMD, and they provide a model for utrophin-A regulation in muscle.


2019 ◽  
Author(s):  
Kamila Kwiecien ◽  
Piotr Brzoza ◽  
Pawel Majewski ◽  
Izabella Skulimowska ◽  
Kamil Bednarczyk ◽  
...  

AbstractChemerin is a chemoattractant protein with adipokine properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. It has gained more attention over the past few years due to its multilevel impact on metabolism and immune responses. The pleiotropic actions of chemerin include chemotaxis of dendritic cells, macrophages and natural killers (NK) subsets, bactericidal activity as well as regulation of adipogenesis and glucose metabolism. Therefore, reflecting the pleiotropic actions of chemerin, expression of RARRES2 is regulated by a variety of inflammatory and metabolic mediators. However, for most cell types, the molecular mechanisms controlling constitutive and regulated chemerin expression are poorly characterized. Here we show that RARRES2 mRNA levels in murine adipocytes are upregulated in vitro and in vivo by acute-phase cytokines, IL-1β and OSM. In contrast to adipocytes, these cytokines exerted a weak, if any, response in mouse hepatocytes, suggesting that the effect of IL-1β and OSM on chemerin expression is specific to fat tissue. Moreover, we show that DNA methylation controls the constitutive expression of chemerin. Bisulfite sequencing analysis showed low methylation levels within −735 to +258 bp of the murine RARRES2 gene promoter in unstimulated adipocytes and hepatocytes. In contrast to these cells, the RARRES2 promoter is highly methylated in B lymphocytes, cells that do not produce chemerin. Together, our findings reveal previously uncharacterized mediators and mechanisms controlling chemerin expression in various cells.


2020 ◽  
Author(s):  
Ying Jiang ◽  
Hong Zhu ◽  
Hong Chen ◽  
Meng-Meng Yang ◽  
Yi-Chen Yu ◽  
...  

Abstract Background: The cardiovascular dysfunction in children born after in vitro fertilization (IVF) has been of great concern, in our study, we aim to explore potential molecular mechanisms for such long-term outcomes.Methods:Real-time qPCR was used to test long non-coding RNA MEG3 and endothelium-derived factors such as endothelial nitric oxide synthase (eNOS), endothelin-1(ET1), and vascular endothelial growth factor (VEGF). ELISA was used to determinate levels of the first and second oxidation products of NO (nitrite, nitrate), ET1 and VEGF. Primary HUVECs collected after caesarean section were treated with different estradiol concentrations in vitro. Additionally, knockdown of MEG3 on HUVEC provided further evidence between MEG3 expression and alteration of NO, ET1, VEGF. Then, by using pyrosequencing, we uncovered the methylation status of the MEG3 region.Results: We found that the expression level of MEG3 was higher in human umbilical vein endothelial cells (HUVECs) of IVF offspring than that in spontaneously born offspring. Furthermore, we found decreased expression of eNOS and VEGF along with elevated expression of ET1 in HUVECs from IVF offspring compared to spontaneously born offspring, accompanied by lower secretion of nitrite, VEGF, and higher secretion of ET1 in the umbilical cord serum of IVF offspring. We confirmed the results from in vivo experiments by demonstrating that high estradiol intrauterine environments lead to abnormal expression of MEG3 and endothelium derived factors. Meanwhile, silencing MEG3 expression decreased ET1 expression, and increased nitrite, nitrate, and VEGF secretion, which could account for the effects we observed in vivo. With pyrosequencing technology, we found that elevated expression of MEG3 in IVF offspring derived HUVECs was the result of hypomethylation of the MEG3 promoter.Conclusions: Our results demonstrated that increased expression of MEG3 in IVF-born HUVECs, accompanied by lower secretion of eNOS and VEGF along with higher secretion of ET1, which is closely related with endothelial dysfunction, together provide a potential mechanism addressing high risk of hypertension in IVF offspring.


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