bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Two Fly LGR (Leucine-Rich Repeat-Containing, G Protein-Coupled Receptor) Proteins Homologous to Vertebrate Glycoprotein Hormone Receptors: Constitutive Activation of Wild-Type Fly LGR1 But Not LGR2 in Transfected Mammalian Cells**This study was supported by NIH Grant HD-23273. The GenBank submission number for fly LGR2 is AF274591.
Authors: Nishi Shinya , Hsu Sheau Yu , Zell Karen , Hsueh Aaron J. W. 
Published: January 2014

AbstractThe receptors for lutropin (LH), FSH, and TSH belong to the large G protein-coupled receptor (GPCR) superfamily and are unique in having a large N-terminal extracellular (ecto-) domain important for interactions with the large glycoprotein hormone ligands. Recent studies indicated the evolution of a large family of the leucine-rich repeat-containing, G protein-coupled receptors (LGRs) with at least seven members in mammals. Based on the sequences of mammalian glycoprotein hormone receptors, we have identified a new LGR in Drosophila melanogaster and named it as fly LGR2 to distinguish it from the previously reported fly LH/FSH/TSH receptor (renamed as fly LGR1). Genomic analysis indicated the presence of 10 exons in fly LGR2 as compared with 16 exons in fly LGR1. The deduced fly LGR2 complementary DNA (cDNA) showed 43 and 64% similarity to the fly LGR1 in the ectodomain and transmembrane region, respectively. Comparison of 12 LGRs from diverse species indicated that these proteins can be divided into three subfamilies and fly LGR1 and LGR2 belong to different subfamilies. Potential signaling mechanisms were tested in human 293T cells overexpressing the fly receptors. Of interest, fly LGR1, but not LGR2, showed constitutive activity as reflected by elevated basal cAMP production in transfected cells. The basal activity of fly LGR1 was further augmented following point mutations of key residues in the intracellular loop 3 or transmembrane VI, similar to those found in patients with familial male precocious puberty. The present study reports the cloning of fly LGR2 and indicates that the G protein-coupling mechanism is conserved in fly LGR1 as compared with the mammalian glycoprotein hormone receptors. The characterization of fly receptors with features similar to mammalian glycoprotein hormone receptors allows a better understanding of the evolution of this unique group of GPCRs and future elucidation of their ligand signaling mechanisms.
Expression of Cyclin-Dependent Kinase Inhibitors in Epiphyseal Chondrocytes Induced to Terminally Differentiate with Thyroid Hormone
Authors: Ballock R. Tracy , Zhou Xiaolan , Mink Lynn M. , Chen Daniel H. C. , Mita Barry C. , Stewart Matthew C. 
Published: January 2014

AbstractA growing body of evidence suggests that systemic hormones and peptide growth factors may exert their effects on cell growth and differentiation in part through regulation of the cell division cycle. We hypothesized that thyroid hormone regulates terminal differentiation of growth plate chondrocytes in part through controlling cell cycle progression at the G1/S restriction point. Our results support this hypothesis by demonstrating that treatment of epiphyseal chondrocytes with thyroid hormone under chemically defined conditions results in the arrest of DNA synthesis and the onset of terminal differentiation, indicating that thyroid hormone is one factor capable of regulating the transition between cell growth and differentiation in these cells. This terminal differentiation process is associated with induction of the cyclin/cyclin-dependent kinase inhibitors p21cip-1, waf-1 and p27kip1, suggesting that thyroid hormone may regulate terminal differentiation in part by arresting cell cycle progression through induction of cyclin-dependent kinase inhibitors.
Local Integration of Glutamate Signaling in the Hypothalamic Paraventricular Region: Regulation of Glucocorticoid Stress Reponses
Authors: Ziegler Dana R. , Herman James P. 
Published: January 2014

Abstract
The present study is a test of the hypothesis that endogenous glutamatergic input to the hypothalamic paraventricular nucleus (PVN) is involved in stress-induced activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. We examined whether corticosterone (CORT) responses to restraint stress could be attenuated by bilateral 50nl microinjections of kynurenic acid (KYN, ionotropic glutamate receptor antagonist) into the medial PVN of conscious rats. Immediately following microinjection, rats were subjected to 30 min restraint, and stress-induced plasma CORT was measured at 30, 60, 120, and 180 min following the onset of restraint. KYN (50 pmol) significantly reduced cumulative CORT responses to acute restraint stress by 24%. In contrast, microinjections centered dorsal to the PVN increased CORT responses by 31%, suggestive of a disinhibition of local PVN-inhibitory input. KYN injections immediately anterior, ventral, or posterior to the PVN had no effect, suggesting an absence of potential diffusion artifacts. These results provide evidence that endogenous glutamate in the PVN and surrounding peri-PVN region plays a physiologically significant role in both generating and limiting glucocorticoid stress responses in awake rats.
Intracellular Regeneration of Glucocorticoids by
11β-Hydroxysteroid Dehydrogenase (11β-HSD)-1 Plays a Key
Role in Regulation of the Hypothalamic-Pituitary-Adrenal Axis: Analysis
of 11β-HSD-1-Deficient Mice**The Wellcome Trust supported this work through a program grant (to J.J.M. and J.R.S.) and a Career Development Fellowship (to M.C.H.).
Authors: Harris Hayley J. , Kotelevtsev Yuri , Mullins John J. , Seckl Jonathan R. , Holmes Megan C. 
Published: January 2014

Abstract
11β-Hydroxysteroid dehydrogenases (11β-HSDs) catalyze interconversion of active corticosterone and inert 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors in vivo. 11β-HSD type 1 is a reductase, locally regenerating active glucocorticoids. To explore the role of this isozyme in the brain, we examined hypothalamic-pituitary-adrenal axis (HPA) regulation in mice homozygous for a targeted disruption of the 11β-HSD-1 gene. 11β-HSD-1-deficient mice showed elevated plasma corticosterone and ACTH levels at the diurnal nadir, with a prolonged corticosterone peak, suggesting abnormal HPA control and enhanced circadian HPA drive. Despite elevated corticosterone levels, several hippocampal and hypothalamic glucocorticoid-sensitive messenger RNAs were normally expressed in 11β-HSD-1-deficient mice, implying reduced effective glucocorticoid activity within neurons. 11β-HSD-1-deficient mice showed exaggerated ACTH and corticosterone responses to restraint stress, with a delayed fall after stress, suggesting diminished glucocorticoid feedback. Indeed, 11β-HSD-1-deficient mice were less sensitive to exogenous cortisol suppression of HPA activation. Thus 11β-HSD-1 amplifies glucocorticoid feedback on the HPA axis and is an important regulator of neuronal glucocorticoid exposure under both basal and stress conditions in vivo.
Inhibition of Ret Oncogene Activity by the Protein Tyrosine Phosphatase SHP1
Authors: Hennige Anita M. , Lammers Reiner , Höppner Wolfgang , Arlt Dorit , Strack Volker , Teichmann Reinhard , Machicao Fausto , Ullrich Axel , Häring Hans-Ulrich , Kellerer Monika 
Published: January 2014

AbstractGermline mutations in the Ret protooncogene give rise to the inherited endocrine cancer syndromes MEN types 2A and 2B and familiar medullary thyroid carcinoma. Although it is well accepted that the constitutive active tyrosine kinase of Ret oncogenes ultimately leads to malignant transformation, it is not clear whether a decrease in the autophosphorylation of oncogenic Ret forms can affect the mitogenic and transforming activities of Ret. Potential modulators of the tyrosine kinase activity of Ret could be tyrosine phosphatases that are expressed in human thyroid tissue. Therefore, we investigated the impact of the tyrosine phosphatases SHP1 and SHP2 on the intrinsic tyrosine kinase activity and oncogenic potency of Ret with a 9-bp duplication in the cysteine-rich domain (codons 634–636), which was described in a patient with MEN type 2A recently. SHP1 and SHP2 were stably overexpressed in NIH3T3 fibroblasts together with Ret-9bp. Coexpression of SHP1 with Ret-9bp reduced the autophosphorylation of Ret-9bp by 19 ± 7% (P = 0.01, n = 4), whereas no effect was seen with SHP2. Furthermore, Ret-9bp could be coimmunoprecipitated with SHP1 but not with SHP2 antibodies. Suppression of the Ret-9bp tyrosine kinase activity by SHP1 caused a decrease in activation of Erk2 (extracellular signal-regulated kinase) and abolished PKB/Akt (protein kinase B) phosphorylation. In addition, diminished Ret-9bp autophosphorylation led to reduced phosphorylation of the transcription factor jun-D. Finally, the inhibitory effect on Ret-9bp signaling resulted in a 40–60% reduction of[ 3H]thymidine incorporation and in reduced ability of NIH3T3 cells to form colonies in soft agar. In conclusion, the data suggest that SHP1 caused a moderate reduction of Ret autophosphorylation, which led to a strong suppression of the Ret oncogene activity.
Early Expression of Pituitary Adenylate Cyclase-Activating Polypeptide and Activation of its Receptor in Chick Neuroblasts*
Authors: Erhardt Nola M. , Fradinger Erica A. , Cervini Laura A. , Rivier Jean E. , Sherwood Nancy M. 
Published: January 2014

AbstractTo investigate the involvement of pituitary adenylate cyclase- activating polypeptide (PACAP) and GH-releasing factor (GRF) during early chick brain development, we established neuroblast- enriched primary cell cultures derived from embryonic day 3.5 chick brain. We measured increases in cAMP generated by several species-specific forms of the peptides. Dose-dependent increases up to 5-fold of control values were measured in response to physiological concentrations of human/salmon, chicken, and tunicate PACAP27. Responses to PACAP38 were more variable, ranging from 5-fold for human PACAP38 to 4-fold for chicken PACAP38, to no significant response for salmon PACAP38, compared with control values. The responses to PACAP38 may reflect a greater difference in peptide structure compared with PACAP27 among species. Increases in cAMP generated by human, chicken, and salmon/carp GRF were not statistically significant, whereas increases in response to lower-range doses of tunicate GRF27-like peptide were significant, but small. We also used immunocytochemistry and Western blot to show synthesis of the PACAP38 peptide. RT-PCR was used to demonstrate that messenger RNAs for PACAP and GRF and a PACAP-specific receptor were present in the cells. This is a first report suggesting an autocrine/paracrine system for PACAP in early chick brain development, based on the presence of the ligand, messages for the ligand and receptor, and activation of the receptor in neuroblast-enriched cultures.
Maternal Undernutrition during Early to Midgestation Programs Tissue-Specific Alterations in the Expression of the Glucocorticoid Receptor, 11β-Hydroxysteroid Dehydrogenase Isoforms, and Type 1 Angiotensin II Receptor in Neonatal Sheep*
Authors: Whorwood C. B. , Firth K. M. , Budge H. , Symonds M. E. 
Published: January 2014

AbstractWe have investigated the effects of maternal nutrient restriction in the sheep during the period of rapid placental growth (i.e. 28–77 days gestation; term = 147 days) on feto-placental growth and expression of the glucocorticoid receptor (GR), types 1 and 2 11β-hydroxysteroid dehydrogenase (11βHSD1, 11βHSD2), and types 1 and 2 angiotensin II receptor (AT1, AT2) in fetal and neonatal offspring. Ewes (n = 63) of similar age, body weight, and body composition were randomly allocated to a nutrient-restricted (NR) group in which they consumed 3.2 MJ/day metabolizable energy (ME; equivalent to 50% of predicted requirements) or to a control group in which they consumed 6.7 MJ/day ME (equivalent to 110% of predicted requirements). After 77 days gestation, ewes from both dietary groups consumed close to 100% of ME requirements up to term. Newborn offspring of NR ewes were of similar body weight, but had increased crown-rump length, greater placental weight, and increased placental/body weight ratio (P &lt; 0.01) compared with controls. Their kidneys were heavier (P &lt; 0.05), but shorter in length, with increased ratios of transverse width to length (P &lt; 0.001).GR messenger RNA (mRNA) expression in neonatal offspring from NR ewes was increased in adrenal, kidney, liver, lung, and perirenal adipose tissue (P &lt; 0.01). Conversely, 11βHSD1 mRNA expression was unaffected, except in perirenal adipose tissue, where it was higher in lambs born to NR ewes (P &lt; 0.01). 11βHSD2 mRNA expression was decreased in adrenals and kidney (P &lt; 0.001). Maternal NR also resulted in significantly increased AT1 expression in those tissues in which expression of GR was increased and/or 11βHSD2 was decreased, i.e. adrenals, kidney, liver, and lung. AT2 expression was unaffected by maternal NR. Although 11βHSD2 mRNA was undetectable in term placenta, it was abundant in midgestation placenta and was lower after maternal NR (P &lt; 0.001). There was close agreement between levels of 11βHSD enzyme (i.e. 11β-dehydrogenase and 11-oxoreductase) activities and abundance of 11βHSD1 mRNA and 11βHSD2 mRNA expression.The persistence of tissue-specific increases in the expression of GR, 11βHSD1 and AT1 and decreases in the expression of 11βHSD2 in adrenals and kidney in newborn offspring in response to a defined period of maternal nutrient restriction during early to midgestation suggests that gene expression has been programmed by nutrient availability to the fetus before birth. These data suggest key potential mechanisms by which maternal nutrition prenatally programs physiological pathways, such as the renin-angiotensin system, in the offspring that may lead to raised blood pressure and other cardiovascular disease risk factors in later life.
Reciprocal Control of Expression of mRNAs for Osteoclast Differentiation Factor and OPG in Osteogenic Stromal Cells by Genistein: Evidence for the Involvement of Topoisomerase II in Osteoclastogenesis
Authors: Yamagishi Takumi , Otsuka Eri , Hagiwara Hiromi 
Published: January 2014

AbstractOsteoclast-like cells, in cocultures with mouse spleen cells and clonal osteogenic stromal ST2 cells, are formed from spleen cells with monocyte/macrophage lineage in response to a combination of osteoclast differentiation factor (RANKL) and OPG, a decoy receptor for RANKL, produced by ST2 cells in response to 1α,25-dihydroxyvitamin D3. Treatment of ST2 cells with the natural isoflavonoid genistein for 6 h before coculture with spleen cells inhibited the formation of tartrate-resistant acid phosphatase-positive osteoclast-like cells. When we measured levels of RANKL mRNA in ST2 cells, we found that genistein decreased the level of this mRNA. By contrast, the level of OPG mRNA was enhanced by genistein. Genistein is a specific inhibitor of topoisomerase II (topo II) and an inhibitor of protein tyrosine kinase, as well as being a potent phytoestrogen. To characterize the mode of action of genistein, we examined the effects of an inactive form of genistein (daidzein), 17β-estradiol, inhibitors of topo II, and inhibitors of tyrosine kinases on the formation of tartrate-resistant acid phosphatase-positive osteoclast-like cells. Among the compounds tested, two inhibitors of topo II, amsacrine and etoposide, attenuated the formation of osteoclast-like cells via reciprocal regulation of the expression of mRNAs for RANKL and OPG in ST2 cells, acting similarly to genistein. Our findings indicate that genistein might inhibit the formation of osteoclast-like cells via inhibition of the activity of topo II, suggesting the novel possibility that topo II might play an important role in osteoclastogenesis.
Calcitonin Induces IL-6 Production via Both PKA and PKC Pathways in the Pituitary Folliculo-Stellate Cell Line
Authors: Kiriyama Yoshimitsu , Tsuchiya Hiroyuki , Murakami Takeshi , Satoh Kumi , Tokumitsu Yukiko 
Published: January 2014

AbstractIt has been demonstrated that calcitonin-binding sites are present in a variety of tissue types, including in the pituitary gland. Interleukin-6 (IL-6) is also produced in the pituitary and it regulates the secretion of various hormones. In this study, we examined the expression of the calcitonin receptor and the mechanism of IL-6 production induced by calcitonin in the pituitary folliculo-stellate cell line (TtT/GF). The mRNA of calcitonin receptor subtype C1a, but not that of C1b, was detected by RT-PCR in TtT/GF cells and in the normal mouse pituitary. Calcitonin increased cAMP accumulation and IL-6 production in a concentration-dependent manner in TtT/GF cells. As calcitonin activates the PKA and PKC pathways, we investigated the contributions of PKA and PKC to IL-6 production. IL-6 production was only slightly increased by either 8-bromo-cAMP (1 mm) or phorbol 12-myristate 13-acetate (100 nm) alone. However, IL-6 was synergistically induced in the presence of both 8-bromo-cAMP (1 mm) and phorbol 12myristate 13-acetate (100 nm). Furthermore, calcitonin-induced IL-6 production was completely suppressed by H-89 (PKA inhibitor) or GF109203X (PKC inhibitor), indicating that the activation of both PKA and PKC is necessary for calcitonin-induced IL-6 production. On the other hand, pertussis toxin (Gi/Go signaling inhibitor) treatment achieved an approximately 9-fold increase in calcitonin-induced IL-6 production. These results show that calcitonin-stimulated IL-6 production is mediated via both PKA- and PKC-signaling pathways, whereas calcitonin also suppresses IL-6 production by activating Gi/Go proteins in folliculo-stellate cells.
Interaction Between Dax-1 and Steroidogenic Factor-1 in Vivo: Increased Adrenal Responsiveness to ACTH in the Absence of Dax-1
Authors: Babu Poda Suresh , Bavers David L. , Beuschlein Felix , Shah Sonalee , Jeffs Baxter , Jameson J. Larry , Hammer Gary D. 
Published: January 2014

AbstractTwo nuclear receptors, dosage-sensitive sex reversal adrenal hypoplasia congenita, critical region on the X chromosome gene-1 (Dax-1) and steroidogenic factor-1 (SF-1), are required for adrenal development and function. In vitro assays suggest that Dax-1 represses SF-1 mediated transcription. In this study, we generated SF-1+/−: Dax-1−/Y mice to examine the role of Dax-1 in SF-1-dependent steroidogenesis in vivo. While the SF-1 expression was impaired in SF-1+/− mice, there was no change in Dax-1 expression in SF-1+/− mice and no change in SF-1 expression in Dax-1−/Y mice. SF-1+/− mice had small adrenal glands with adrenal hypoplasia and cellular hypertrophy. The loss of Dax-1 in SF-1+/−: Dax-1−/Y mice reversed the decreased adrenal weight and histological abnormalities observed in SF-1+/− mice. SF-1+/− mice had elevated ACTH and the lowest corticosterone following restraint stress. In contrast, Dax-1−/Y mice had elevated corticosterone and decreased ACTH. Adrenal responsiveness (ACTH/corticosterone) was highest in Dax-1−/Y mice, intermediate in WT and SF-1+/−: Dax-1−/Y mice, and lowest in SF-1+/− mice. In accordance with these findings, ACTH stimulation testing resulted in the highest levels of corticosterone in the Dax-1−/Y mice. Protein levels of P450c21 and the ACTH receptor were increased in Dax-1−/Y mice and intermediate in SF-1+/−: Dax-1−/Y mice following chronic food deprivation. These results are consistent with a model in which Dax-1 functions to inhibit SF-1-mediated steroidogenesis in vivo.
Bone Morphogenetic Proteins Stimulate Angiogenesis through Osteoblast-Derived Vascular Endothelial Growth Factor A
Authors: Deckers Martine M. L. , van Bezooijen Rutger L. , van der Horst Geertje , Hoogendam Jakomijn , van der Bent Chris , Papapoulos Socrates E. , Löwik Clemens W. G. M. 
Published: January 2014

AbstractDuring bone formation and fracture healing there is a cross-talk between endothelial cells and osteoblasts. We previously showed that vascular endothelial growth factor A (VEGF-A) might be an important factor in this cross-talk, as osteoblast-like cells produce this angiogenic factor in a differentiation-dependent manner. Moreover, exogenously added VEGF-A enhances osteoblast differentiation. In the present study we investigated, given the coupling between angiogenesis and bone formation, whether bone morphogenetic proteins (BMPs) stimulate osteoblastogenesis and angiogenesis through the production of VEGF-A. For this we used the murine preosteoblast-like cell line KS483, which forms mineralized nodules in vitro, and an angiogenesis assay comprising 17-d-old fetal mouse bone explants that have the ability to form tube-like structures in vitro.Treatment of KS483 cells with BMP-2, -4, and -6 enhanced nodule formation, osteocalcin mRNA expression, and subsequent mineralization after 18 d of culture. This was accompanied by a dose-dependent increase in VEGF-A protein levels throughout the culture period. BMP-induced osteoblast differentiation, however, was independent of VEGF-A, as blocking VEGF-A activity by a VEGF-A antibody or a VEGF receptor 2 tyrosine kinase inhibitor did not affect BMP-induced mineralization.To investigate whether BMPs stimulate angiogenesis through VEGF-A, BMPs were assayed for their angiogenic activity. Treatment of bone explants with BMPs enhanced angiogenesis. This was inhibited by soluble BMP receptor 1A or noggin. In the presence of a VEGF-A antibody, both unstimulated and BMP-stimulated angiogenesis were arrested. Conditioned media of KS483 cells treated with BMPs also induced a strong angiogenic response, which was blocked by antimouse VEGF-A but not by noggin. These effects were specific for BMPs, as TGFβ inhibited osteoblast differentiation and angiogenesis while stimulating VEGF-A production.These findings indicate that BMPs stimulate angiogenesis through the production of VEGF-A by osteoblasts. In conclusion, VEGF-A produced by osteoblasts in response to BMPs is not involved in osteoblast differentiation, but couples angiogenesis to bone formation.
Leptin-Induced Leptin Resistance Reveals Separate Roles for the Anorexic and Thermogenic Responses in Weight Maintenance
Authors: Scarpace Philip J. , Matheny Michael , Zhang Yi , Shek Eugene W. , Prima Victor , Zolotukhin Sergei , Tümer Nihal 
Published: January 2014

Abstract
The purpose of this study was to determine whether leptin induces leptin resistance by examining the temporal attenuation of the anorexic and energy expenditure responses to leptin. We administered recombinant adeno-associated virus encoding rat leptin cDNA or control viral vector into mildly obese rats for 138 d and compared these results with those from pair-fed rats. We measured food consumption, body weight, oxygen consumption, leptin signal transduction, and brown adipose tissue uncoupling protein 1. The anorexic response attenuated by d 25, whereas the increase in energy expenditure persisted for 83 d before attenuating. Despite attenuation of physiological responses, phosphorylated signal transducer and activator of transcription-3 remained elevated for the duration of the study. The temporal differential attenuation of the anorexic and thermogenic responses allowed us to determine the relative contributions of each response to weight maintenance. The anorexic response predominantly mediated the initial loss of body weight, but only the energy expenditure response was necessary to maintain the reduced weight. This study provides evidence that leptin induces leptin resistance. The leptin resistance was associated with persistent elevation in hypothalamic phosphorylated signal transducer and activator of transcription-3 and was characterized by a rapid attenuation of the anorexic response and slower onset for the attenuation of the energy expenditure response. We propose that both elevated leptin and obesity may be necessary for the development of leptin resistance.