Prolactin and the expression of suppressor of cytokine signaling-3 in the sheep adrenal gland before birth

2006 ◽  
Vol 291 (5) ◽  
pp. R1399-R1405 ◽  
Author(s):  
S. Gentili ◽  
J. S. Schwartz ◽  
M. J. Waters ◽  
I. C. McMillen
Keyword(s):  
Adrenal Gland ◽  
Mrna Expression ◽  
Tissue Growth ◽  
Late Gestation ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Subsequent Increase ◽  
Fetal Sheep

The fetal pituitary-adrenal axis plays a key role in the fetal response to intrauterine stress and in the timing of parturition. The fetal sheep adrenal gland is relatively refractory to stimulation in midgestation (90–120 days) before the prepartum activation, which occurs around 135 days gestation (term = 147 ± 3 days). The mechanisms underlying the switch from adrenal quiescence to activation are unclear. Therefore, we have investigated the expression of suppressor of cytokine signaling-3 (SOCS-3), a putative inhibitor of tissue growth in the fetal sheep adrenal between 50 and 145 days gestation and in the adrenal of the growth-restricted fetal sheep in late gestation. SOCS-3 is activated by a range of cytokines, including prolactin (PRL), and we have, therefore, determined whether PRL administered in vivo or in vitro stimulates SOCS-3 mRNA expression in the fetal adrenal in late gestation. There was a decrease ( P < 0.005) in SOCS-3 expression in the fetal adrenal between 54 and 133 days and between 141 and 144 days gestation. Infusion of the dopaminergic agonist, bromocriptine, which suppressed fetal PRL concentrations but did not decrease adrenal SOCS-3 mRNA expression. PRL administration, however, significantly increased adrenal SOCS-3 mRNA expression ( P < 0.05). Similarly, there was an increase ( P < 0.05) in SOCS-3 mRNA expression in adrenocortical cells in vitro after exposure to PRL (50 ng/ml). Placental and fetal growth restriction had no effect on SOCS-3 expression in the adrenal during late gestation. In summary, the decrease in the expression of the inhibitor SOCS-3 after 133 days gestation may be permissive for a subsequent increase in fetal adrenal growth before birth. We conclude that factors other than PRL act to maintain adrenal SOCS-3 mRNA expression before 133 days gestation but that acute elevations of PRL can act to upregulate adrenal SOCS-3 expression in the sheep fetus during late gestation.

scholarly journals Angiotensin II infusion in vivo does not modulate cortisol secretion in the late-gestation ovine fetus

1998 ◽  
Vol 275 (2) ◽  
pp. R357-R362 ◽  
Author(s):  
Kirsten R. Poore ◽  
I. Ross Young ◽  
Benedict J. Canny ◽  
Geoffrey D. Thorburn
Keyword(s):  
Angiotensin Ii ◽  
Adrenal Gland ◽  
Late Gestation ◽  
Treatment Groups ◽  
Arterial Blood ◽  
Basal Cortisol ◽  
Ovine Fetus

Maturation of the fetal adrenal gland is critical for the onset of ovine parturition. It has long been proposed that the fetal adrenal gland may be under inhibitory influences during late gestation. In vitro evidence has suggested that angiotensin II may be such an inhibitory factor and may help to prevent a premature increase in cortisol concentrations. The aim of this study was to test the effect of angiotensin II infusion in vivo on basal cortisol concentrations and fetal adrenal responsiveness to an ACTH-(1—24) challenge. Fetuses received a continuous infusion of either angiotensin II (100 ng ⋅ min−1 ⋅ kg−1; n = 7) or saline (2 ml/h; n = 4), which commenced at 140 days of gestation (GA) and continued for a total of 50 h. Adrenal responsiveness to the administration of ACTH-(1—24) (5 μg/kg) was determined during angiotensin II or saline infusions at both 2 and 48 h after infusion onset. Angiotensin II had no significant effect on adrenal responsiveness after acute (2 h) or chronic (48 h) infusion. There was no effect of saline or angiotensin II infusion on basal immunoreactive ACTH or cortisol concentrations after 2 h, but there was a significant increase in basal cortisol concentrations in both treatment groups by 48 h, probably reflecting the normal rise in cortisol concentrations at this GA. Mean arterial blood pressure was significantly increased in angiotensin II-infused fetuses only. This study has therefore found no evidence to suggest that angiotensin II infusion in vivo modulates fetal basal cortisol concentrations or adrenal responsiveness in the last week of gestation, in contrast with previous in vitro studies. These results throw into question the proposed role of angiotensin II as a negative modulator of adrenal function in the ovine fetus.

GRF treatment of late pregnant ewes alters maternal and fetal somatotropic axis activity

1991 ◽  
Vol 260 (4) ◽  
pp. E575-E580 ◽  
Author(s):  
M. M. Blanchard ◽  
C. G. Goodyer ◽  
J. Charrier ◽  
G. Kann ◽  
R. Garcia-Villar ◽  
...  
Keyword(s):  
Plasma Levels ◽  
Late Gestation ◽  
Placental Lactogen ◽  
Maximal Response ◽  
Pituitary Cells ◽  
In Vitro Test ◽  
Fetal Sheep ◽  
Igf I

To examine the effects of anabolic agents given during late gestation on the maternal and fetal somatotropic axes, we injected pregnant ewes twice daily with 0.15 mg somatocrinin (GRF)-(1-29) for 10 days beginning on day 130 of gestation. Maternal and fetal endocrine changes were compared with control animals using both in vivo and in vitro approaches. Treatment with GRF increased maternal plasma levels of growth hormone (GH) and insulin-like growth factor I (IGF-I;P less than 0.05) but not IGF-II. Under in vitro test conditions, maternal pituitary cells showed a greater maximal response (P less than 0.001) to GRF. In the fetuses of treated ewes, cord plasma GH levels were not significantly increased compared with controls. These animals had similar IGF-I but higher IGF-II (P less than 0.05) plasma levels. The maximal response of fetal pituitary cells to GRF was increased (P less than 0.001). GRF treatment had no influence on maternal and fetal pituitary cell responses to somatostatin under either basal or GRF-stimulated conditions. In addition, these treatments did not affect plasma levels of placental lactogen, glucose, or free fatty acids in the maternal and fetal sheep. These data are compatible with the hypothesis that treatment of pregnant ewes in the last days of gestation with GRF could support accelerated fetal growth.

Differential regulation of suppressor of cytokine signaling-3 in the liver and adipose tissue of the sheep fetus in late gestation

2006 ◽  
Vol 290 (4) ◽  
pp. R1044-R1051 ◽  
Author(s):  
Sheridan Gentili ◽  
Michael J. Waters ◽  
I. Caroline McMillen
Keyword(s):  
Adipose Tissue ◽  
Mrna Expression ◽  
Fetal Growth ◽  
Fetal Liver ◽  
Late Gestation ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Perirenal Adipose Tissue ◽  
Plasma Prl ◽  
Sheep Fetus

It is unknown whether the JAK/STAT/suppressor of cytokine signaling-3 (SOCS-3) intracellular signaling pathway plays a role in tissue growth and metabolism during fetal life. We investigated whether there is a differential profile of SOCS-3 expression in the liver and perirenal adipose tissue during the period of increased fetal growth in late gestation and the impact of fetal growth restriction on SOCS-3 expression in the fetal liver. We also determined whether basal SOCS-3 expression in the fetal liver and perirenal adipose tissue is regulated by endogenous fetal prolactin (PRL). SOCS-3 mRNA abundance was higher in the liver than in the pancreas, spleen, and kidney of the sheep fetus during late gestation. In the liver, SOCS-3 mRNA expression was increased ( P < 0.05) between 125 ( n = 4) and 145 days ( n = 7) gestation and lower ( P < 0.05) in growth-restricted compared with normally grown fetal sheep in late gestation. The relative expression of SOCS-3 mRNA in the fetal liver was directly related to the mean plasma PRL concentrations during a 48-h infusion of either a dopaminergic agonist, bromocriptine ( n = 7), or saline ( n = 5), such that SOCS-3 mRNA expression was lower when plasma PRL concentrations decreased below ∼20 ng/ml [ y = 0.99 − (2.47/ x) + (4.96/ x2); r2 = 0.91, P < 0.0001, n = 12]. No relationship was shown between the abundance of phospho-STAT5 in the fetal liver and circulating PRL. SOCS-3 expression in perirenal adipose tissue decreased ( P < 0001) between 90–91 ( n = 6) and 140–145 days ( n = 9) gestation and was not related to endogenous PRL concentrations. Thus SOCS-3 is differentially expressed and regulated in key fetal tissues and may play an important and tissue-specific role in the regulation of cellular proliferation and differentiation before birth.

scholarly journals miR-155 accelerates proliferation of mouse hepatocytes during liver regeneration by directly targeting SOCS1

2018 ◽  
Vol 315 (4) ◽  
pp. G443-G453 ◽  
Author(s):  
Xia Lin ◽  
Li Chen ◽  
Haiyan Li ◽  
Yu Liu ◽  
Yanhong Guan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Molecular Mechanisms ◽  
Pharmacological Intervention ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Proliferation Of Hepatocytes

Liver regeneration after two-thirds partial hepatectomy (PH) is a clinically significant repair process for restoring proper liver architecture. Although microRNA-155 (miR-155) has been found to serve as a crucial microRNA regulator that controls liver cell function and proliferation, little is known about its specific role in the regenerating liver. Using a mouse model with miR-155 overexpression or miR-155 knockout, we investigated the molecular mechanisms of miR-155 in liver regeneration. We found a marked induction of miR-155 in C57BL/6 mice after PH. Furthermore, RL-m155 mice showed enhanced liver regeneration as a result of accelerated progression of hepatocytes into the cell cycle, mainly through an increase in cyclin levels. However, proliferation of hepatocytes was delayed in miR-155-deficient livers. Expression of suppressor of cytokine signaling 1 (SOCS1) was dramatically downregulated in the process of liver regeneration, and enhancement of SOCS1 contributed to impaired proliferation of hepatocytes. Additionally, in vitro and in vivo experiments showed that adenovirus- or adeno-associated virus-mediated overexpression of SOCS1 attenuated improved liver regeneration induced by miR-155 overexpression. Our study shows that miR-155 is a pro-proliferative regulator in liver regeneration by facilitating the cell cycle and directly targeting SOCS1. NEW & NOTEWORTHY Our findings suggest a microRNA-155 (miR-155)-mediated positive regulation pattern in liver regeneration. A series of in vivo and in vitro studies showed that miR-155 upregulation enhanced partial hepatectomy-induced proliferation of hepatocytes by promoting the cell cycle without inducing DNA damage or apoptosis. Suppressor of cytokine signaling 1, a target gene of miR-155, antagonized the proliferation-promoting effect of miR-155. Therefore, pharmacological intervention targeting miR-155 may be therapeutically beneficial in various liver diseases.

scholarly journals Unique Expression of Suppressor of Cytokine Signaling 3 Is Essential for Classical Macrophage Activation in Rodents In Vitro and In Vivo

2008 ◽  
Vol 180 (9) ◽  
pp. 6270-6278 ◽  
Author(s):  
Yu Liu ◽  
Keith N. Stewart ◽  
Eileen Bishop ◽  
Carylyn J. Marek ◽  
David C. Kluth ◽  
...  
Keyword(s):  
Macrophage Activation ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling

Decreased nutrient-stimulated insulin secretion in chronically hypoglycemic late-gestation fetal sheep is due to an intrinsic islet defect

2006 ◽  
Vol 291 (2) ◽  
pp. E404-E411 ◽  
Author(s):  
Paul J. Rozance ◽  
Sean W. Limesand ◽  
William W. Hay
Keyword(s):  
Insulin Secretion ◽  
Late Gestation ◽  
Human Infants ◽  
Fetal Sheep ◽  
Isolated Pancreatic Islets ◽  
Acute Hypoglycemia ◽  
Arterial Plasma ◽  
Glucose Stimulated Insulin Secretion

We measured in vivo and in vitro nutrient-stimulated insulin secretion in late gestation fetal sheep to determine whether an intrinsic islet defect is responsible for decreased glucose-stimulated insulin secretion (GSIS) in response to chronic hypoglycemia. Control fetuses responded to both leucine and lysine infusions with increased arterial plasma insulin concentrations (average increase: 0.13 ± 0.05 ng/ml leucine; 0.99 ± 0.26 ng/ml lysine). In vivo lysine-stimulated insulin secretion was decreased by chronic (0.37 ± 0.18 ng/ml) and acute (0.27 ± 0.19 ng/ml) hypoglycemia. Leucine did not stimulate insulin secretion following acute hypoglycemia but was preserved with chronic hypoglycemia (0.12 ± 0.09 ng/ml). Isolated pancreatic islets from chronically hypoglycemic fetuses had normal insulin and DNA content but decreased fractional insulin release when stimulated with glucose, leucine, arginine, or lysine. Isolated islets from control fetuses responded to all nutrients. Therefore, chronic late gestation hypoglycemia causes defective in vitro nutrient-regulated insulin secretion that is at least partly responsible for diminished in vivo GSIS. Chronic hypoglycemia is a feature of human intrauterine growth restriction (IUGR) and might lead to an islet defect that is responsible for the decreased insulin secretion patterns seen in human IUGR fetuses and low-birth-weight human infants.

scholarly journals MiR-142-3p Suppresses SOCS6 Expression and Promotes Cell Proliferation in Nasopharyngeal Carcinoma

2015 ◽  
Vol 36 (5) ◽  
pp. 1743-1752 ◽  
Author(s):  
Xiaoming Qi ◽  
Jianqiang Li ◽  
Changbo Zhou ◽  
Chunlei Lv ◽  
Min Tian
Keyword(s):  
Cell Proliferation ◽  
Nasopharyngeal Carcinoma ◽  
Cell Cycle Progression ◽  
Therapeutic Strategy ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Cycle Progression ◽  
Direct Target

Background/Aims: An increasing number of studies show that microRNAs (miRNAs) play crucial roles in nasopharyngeal carcinoma (NPC) tumorigenesis. The aim of our study was to investigate the biological roles and mechanisms of miR-142-3p in NPC. Methods: miR-142-3p expression was examined in NPC specimens and nasopharyngitis biopsy samples by quantitative real-time PCR. The biological functions of miR-142-3p were studied using a series of in vitro and in vivo approaches. Results: miR-142-3p is over-expressed in NPC tissues and cell lines. Knockdown of miR-142-3p significantly inhibited cell proliferation and cell cycle progression in vitro, and suppressed tumor growth in a mouse model. Suppressor of cytokine signaling 6 (SOCS6) was identified as a direct target of miR-142-3p, and miR-142-3p down-regulated the expression of SOCS6 by directly binding to its 3′untranslated region (UTR). Knockdown of SOCS6 abrogated the effects of miR-142-3p down-regulation. Conclusion: These findings indicate that miR-142-3p regulates NPC development by down-regulating SOCS6 expression and suggest that modulation of miR-142-3p expression could be a therapeutic strategy for NPC.

scholarly journals Gestational age-dependent changes in the levels of mRNAs encoding cortisol biosynthetic enzymes and IGF-II in the adrenal gland of fetal sheep during prolonged hypoxemia

1998 ◽  
Vol 159 (2) ◽  
pp. 257-264 ◽  
Author(s):  
GA Braems ◽  
VK Han ◽  
Keyword(s):  
Adrenal Gland ◽  
Gestational Age ◽  
Tissue Growth ◽  
Late Gestation ◽  
Fetal Sheep ◽  
Pronounced Increase ◽  
Fetal Organ ◽  
Adrenal Steroidogenesis ◽  
Arterial Ph ◽  
Resultant Increase

Hypoxemia represents a major stress for the fetus, and is associated with alterations and adaptations in cardiovascular, metabolic and endocrine responses, which in turn may affect tissue growth and differentiation. To determine the effects of hypoxemia on fetal adrenal activity and growth, we subjected sheep fetuses at days 126-130 and 134-136 (term 145 days) to reduced PaO2 by reducing the maternal fraction of oxygen for 48 h (mean reduction of 6.8 mmHg), without change in arterial pH or PaCO2. This stimulus resulted in similar increases in the plasma immunoreactiveACTH response at both ages. Among adrenal steroids, plasma cortisol (C21Delta4) rose in both groups of animals, but plasma androstenedione (C19Delta4) declined marginally, resulting in a pronounced increase in the cortisol:androstenedione ratio in the plasma that was greater and more sustained in the older fetuses. In the younger fetuses, after 48 h of hypoxemia, there were no significant changes in mRNAs encoding steroidogenic enzymes in the fetal adrenal gland. However, in the older fetuses, hypoxemia resulted in significantly increased levels of mRNAs encoding P450scc, P450C21 and 3beta-hydroxysteroid dehydrogenase, but not for P450C17, in the fetal adrenal gland. Levels of IGF-II mRNA in the fetal adrenal gland fell in both groups of fetuses, and this response was greater at the later gestational age. We conclude that sustained hypoxemia is a potent stimulus which activates adrenal steroidogenesis in the late gestation fetal sheep. The resultant increase in cortisol synthesis is associated with decreased expression of adrenal IGF-II mRNA. We speculate that this relationship might influence patterns of fetal organ growth and differentiative function in response to fetal stress such as hypoxemia.

IL-22-mediated liver cell regeneration is abrogated by SOCS-1/3 overexpression in vitro

2007 ◽  
Vol 292 (4) ◽  
pp. G1019-G1028 ◽  
Author(s):  
Stephan Brand ◽  
Julia Dambacher ◽  
Florian Beigel ◽  
Kathrin Zitzmann ◽  
Malte H. J. Heeg ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mrna Expression ◽  
Liver Cell ◽  
Cytokine Signaling ◽  
Cell Regeneration ◽  
Mrna Levels ◽  
Hepatic Cells ◽  
Hepatocyte Regeneration

The IL-10-like cytokine IL-22 is produced by activated T cells. In this study, we analyzed the role of this cytokine system in hepatic cells. Expression studies were performed by RT-PCR and quantitative PCR. Signal transduction was analyzed by Western blot experiments and ELISA. Cell proliferation was measured by MTS and [3H]thymidine incorporation assays. Hepatocyte regeneration was studied in in vitro restitution assays. Binding of IL-22 to its receptor complex expressed on human hepatic cells and primary human hepatocytes resulted in the activation of MAPKs, Akt, and STAT proteins. IL-22 stimulated cell proliferation and migration, which were both significantly inhibited by the phosphatidylinositol 3-kinase inhibitor wortmannin. IL-22 increased the mRNA expression of suppressor of cytokine signaling (SOCS)-3 and the proinflammatory cytokines IL-6, IL-8, and TNF-α. SOCS-1/3 overexpression abrogated IL-22-induced STAT activation and decreased IL-22-mediated liver cell regeneration. Hepatic IL-22 mRNA expression was detectable in different forms of human hepatitis, and hepatic IL-22 mRNA levels were increased in murine T cell-mediated hepatitis in vivo following cytomegalovirus infection, whereas no significant differences were seen in an in vivo model of ischemia-reperfusion injury. In conclusion, IL-22 promotes liver cell regeneration by increasing hepatic cell proliferation and hepatocyte migration through the activation of Akt and STAT signaling, which is abrogated by SOCS-1/3 overexpression.

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