scholarly journals 043. Role of TGFβ in adrenal steroidogenesis before birth

2004 ◽  
Vol 16 (9) ◽  
pp. 43
Author(s):  
C. L. Coulter
Keyword(s):  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Hepatic Glucose Production ◽  
Mammalian Species ◽  
Late Gestation ◽  
Fetal Life ◽  
Fetal Sheep ◽  
Adrenal Steroidogenesis ◽  
Metabolic Systems

During mammalian development there are periods when the fetal adrenal is either relatively refractory or increasingly sensitive to trophic stimulation. This pattern of regulation of adrenal growth and function ensures that the fetal lungs, liver, brain and kidney are exposed in a programmed temporal sequence to the genomic actions of circulating glucocorticoids. A range of studies in the rat and sheep have also demonstrated that exposure to excess glucocorticoids at inappropriate times in fetal life inhibits fetal growth and permanently reprograms the development of the cardiovascular and metabolic systems resulting in postnatal hypertension, abnormal hepatic glucose production and poor glucose tolerance In most mammalian species, there are therefore a range of mechanisms that protect the fetus from exposure to glucocorticoids of either maternal or fetal origin at inappropriate times in gestation. The factors that act to maintain periods of adrenal quiescence are not known. There is evidence that intra-adrenal transforming growth factor beta 1 (TGFβ1) is an inhibitor of adrenocortical steroidogenesis in the adult. In recent studies, we have demonstrated that expression of TGFβ1 is high in the fetal sheep adrenal at around 100�days gestation and that adrenal TGFβ1 expression then falls with increasing gestational age and is lowest immediately after birth. Following the activation of adrenal cytochrome P450 C17 (CYP17), there is an inverse relationship between adrenal TGFβ1 and CYP17 expression and TGFβ1 may therefore play a novel inhibitory role in the regulation of adrenal steroidogenesis during mid and late gestation. Whilst functional activation of the fetal adrenal is dependent on the fetal hypothalamo–pituitary axis, adrenal TGFβ1 mRNA expression is not altered by disconnection of the fetal hypothalamus and pituitary in late gestation. It therefore appears unlikely that TGFβ1 mRNA expression is regulated directly by either bioactive ACTH or cortisol in late gestation. The mechanism by which TGFβ1 expression is upregulated in mid gestation remains to be determined.

scholarly journals Chronic anemic hypoxemia increases plasma glucagon and hepatic PCK1 mRNA in late-gestation fetal sheep

2016 ◽  
Vol 311 (1) ◽  
pp. R200-R208 ◽  
Author(s):  
Christine Culpepper ◽  
Stephanie R. Wesolowski ◽  
Joshua Benjamin ◽  
Jennifer L. Bruce ◽  
Laura D. Brown ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Late Gestation ◽  
Hepatic Glycogen ◽  
Plasma Glucagon ◽  
Low Oxygen ◽  
Fetal Sheep ◽  
Hepatic Glucose ◽  
Arterial Plasma

Hepatic glucose production (HGP) normally begins just prior to birth. Prolonged fetal hypoglycemia, intrauterine growth restriction, and acute hypoxemia produce an early activation of fetal HGP. To test the hypothesis that prolonged hypoxemia increases factors which regulate HGP, studies were performed in fetuses that were bled to anemic conditions (anemic: n = 11) for 8.9 ± 0.4 days and compared with control fetuses ( n = 7). Fetal arterial hematocrit and oxygen content were 32% and 50% lower, respectively, in anemic vs. controls ( P < 0.005). Arterial plasma glucose was 15% higher in the anemic group ( P < 0.05). Hepatic mRNA expression of phosphonenolpyruvate carboxykinase ( PCK1) was twofold higher in the anemic group ( P < 0.05). Arterial plasma glucagon concentrations were 70% higher in anemic fetuses compared with controls ( P < 0.05), and they were positively associated with hepatic PCK1 mRNA expression ( P < 0.05). Arterial plasma cortisol concentrations increased 90% in the anemic fetuses ( P < 0.05), but fetal cortisol concentrations were not correlated with hepatic PCK1 mRNA expression. Hepatic glycogen content was 30% lower in anemic vs. control fetuses ( P < 0.05) and was inversely correlated with fetal arterial plasma glucagon concentrations. In isolated primary fetal sheep hepatocytes, incubation in low oxygen (3%) increased PCK1 mRNA threefold compared with incubation in normal oxygen (21%). Together, these results demonstrate that glucagon and PCK1 may potentiate fetal HGP during chronic fetal anemic hypoxemia.

Regulation of Hepatic Glucose Production by Transforming Growth Factor Beta 1 via Protein Kinase A

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 2441-PUB ◽  
Author(s):  
QUAN PAN ◽  
YUNMEI CHEN ◽  
HUI YAN ◽  
WANBAO YANG ◽  
ZHENG SHEN ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Hepatic Glucose ◽  
Growth Factor Beta ◽  
Kinase A

Anemic Hypoxemia Reduces Myoblast Proliferation and Muscle Growth in Late Gestation Fetal Sheep

2021 ◽  
Author(s):  
Paul J. Rozance ◽  
Stephanie R Wesolowski ◽  
Sonnet S. Jonker ◽  
Laura D Brown
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Muscle Growth ◽  
Late Gestation ◽  
Whole Body ◽  
Myoblast Differentiation ◽  
Fetal Sheep ◽  
Body Protein ◽  
Skeletal Muscle Growth ◽  
Myoblast Proliferation

Fetal skeletal muscle growth requires myoblast proliferation, differentiation, and fusion into myofibers in addition to protein accretion for fiber hypertrophy. Oxygen is an important regulator of this process. Therefore, we hypothesized that fetal anemic hypoxemia would inhibit skeletal muscle growth. Studies were performed in late gestation fetal sheep that were bled to anemic, and therefore hypoxemic, conditions beginning at ~125 days of gestation (term = 148 days) for 9 ± 0 days (n=19) and compared to control fetuses (n=16). A metabolic study was performed on gestational day ~134 to measure fetal protein kinetic rates. Myoblast proliferation and myofiber area were determined in biceps femoris (BF), tibialis anterior (TA), and flexor digitorum superficialis (FDS) muscles. mRNA expression of muscle regulatory factors was determined in BF. Fetal arterial hematocrit and oxygen content were 28% and 52% lower, respectively, in anemic fetuses. Fetal weight and whole-body protein synthesis, breakdown, and accretion rates were not different between groups. Hindlimb length, however, was 7% shorter in anemic fetuses. TA and FDS muscles weighed less and FDS myofiber area was smaller in anemic fetuses compared to controls. The percentage of Pax7+ myoblasts that expressed Ki67 was lower in BF and tended to be lower in FDS from anemic fetuses indicating reduced myoblast proliferation. There was less MYOD and MYF6 mRNA expression in anemic vs. control BF consistent with reduced myoblast differentiation. These results indicate that fetal anemic hypoxemia reduced muscle growth. We speculate that fetal muscle growth may be improved by strategies that increase oxygen availability.

Regulation of mesenchymal extracellular matrix protein synthesis by transforming growth factor-beta and glucocorticoids in tumor stroma

1995 ◽  
Vol 108 (6) ◽  
pp. 2153-2162 ◽  
Author(s):  
J.F. Talts ◽  
A. Weller ◽  
R. Timpl ◽  
M. Ekblom ◽  
P. Ekblom
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Growth Factor ◽  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Tenascin C ◽  
Extracellular Matrix Components ◽  
Growth Factor Beta ◽  
Matrix Components

We have here studied the composition and regulation of stromal extracellular matrix components in an experimental tumor model. Nude mice were inoculated with WCCS-1 cells, a human Wilms' tumor cell line. In the formed tumors the stroma was found to contain mesenchymal extracellular matrix proteins such as tenascin-C, fibulins-1 and 2 and fibronectin, but no nidogen. Nidogen was confined to basement membranes of tumor blood vessels. Since glucocorticoids have been shown to downregulate tenascin-C expression in vitro, we tested whether dexamethasone can influence biosynthesis of extracellular matrix components during tumor formation in vivo. A downregulation of tenascin-C mRNA and an upregulation of fibronectin mRNA expression by dexamethasone was noted. Transforming growth factor-beta 1 mRNA levels were unaffected by the dexamethasone treatment. Glucocorticoids can thus downregulate tenascin-C synthesis although local stimulatory growth factors are present. The competition between a negative and a positive extrinsic factor on synthesis of stromal extracellular matrix components was studied in a fibroblast/preadipocyte cell line. Transforming growth factor-beta 1 stimulated tenascin-C synthesis but did not affect fibronectin or fibulin-2 synthesis. Dexamethasone at high concentrations could completely suppress the effect of transforming growth factor-beta 1 on tenascin-C mRNA expression. Transforming growth factor-beta 1 could in turn overcome the downregulation of tenascin-C mRNA expression caused by a lower concentration of dexamethasone. We therefore suggest that the limited expression of tenascin-C in part is due to a continuous suppression by physiological levels of glucocorticoids, which can be overcome by local stimulatory growth factors when present in sufficient amounts.

Abstract 782: Fra2 Mediates Oxygen-induced TGFbeta-1 mRNA Expression In Adult Cardiac Fibroblasts: Significance In Myocardial Fibrosis Following Ischemia-reperfusion Injury

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Sashwati Roy ◽  
Savita Khanna ◽  
Chandan K Sen
Keyword(s):  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Ischemia Reperfusion Injury ◽  
Cardiac Fibroblasts ◽  
Ischemia Reperfusion ◽  
Luciferase Reporter ◽  
Mrna Levels

Background . Transforming growth factor beta-1 (TGFbeta-1) is a key cytokine implicated in the development of cardiac fibrosis following ischemia-reperfusion (IR) injury. The profibrotic effects of TGFbeta-1 are primarily attributable to the differentiation of cardiac fibroblasts (CF) to myofibroblasts. Previously, we have reported perceived hyperoxia (Circ Res 92:264 –71), sub-lethal reoxygenation shock during IR, induces differentiation of CF to myofibroblasts at the infarct site. The mechanisms underlying oxygen-sensitive induction of TGFbeta-1 mRNA remain to be characterized. Hypothesis . Fra2 mediates oxygen-induced TGFbeta-1 mRNA expression in adult cardiac fibroblasts. Methods. TGFbeta-1 mRNA expression in infarct tissue was investigated in an IR injury model. The left anterior descending coronary artery of mice was transiently occluded for 60 minutes followed by reperfusion to induce IR injury. Spatially resolved infarct and non-infarct tissues were collected at 0, 1, 3, 5, and 7 days post-IR using laser capture microdissection. TGFbeta-1 mRNA levels were measured using real-time PCR. To investigate the role of oxygen in the regulation of TGFbeta-1, we used our previously reported model of perceived hyperoxia where CF (from 5wks old mice) after isolation were cultured at 5%O 2 (physiological pO 2 ) followed by transferring them to 20%O 2 to induce hyperoxic insult. Results & Conclusions. In vivo, a significant increase (p<0.01; n=5) in TGFbeta-1 mRNA was observed at the infarct site already at day 1 post-IR. The levels continued to increase until day 7 post-IR. In vitro, exposure of CF to 20%O 2 hyperoxic insult induced TGFbeta-1 mRNA (p<0.001; n=4) and protein (p<0.01; n=4) expression. Using a TGFbeta-1 promoter-luciferase reporter and DNA binding assays, we collected first evidence that AP-1 and its component Fra2 as major mediators of oxygen-induced TGFbeta-1 expression. Exposure to 20%O 2 resulted in increased localization of Fra2 in nucleus. siRNA-dependent Fra-2 knock-down completely abrogated oxygen-induced TGFbeta1 expression. In conclusion, this study presents first evidence that Fra-2 is involved in inducible TGFbeta1 expression in CF. Fra2 was noted as being central in regulating oxygen-induced TGFbeta-1 expression.s

scholarly journals Expression of mRNA for IL1 beta, IL6 and TGF beta 1 in developing human bone and cartilage.

1994 ◽  
Vol 42 (6) ◽  
pp. 733-744 ◽  
Author(s):  
R A Dodds ◽  
K Merry ◽  
A Littlewood ◽  
M Gowen
Keyword(s):  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Close Association ◽  
Interleukin 1 ◽  
Cell Types ◽  
Tgf Beta ◽  
Specific Stage ◽  
Growth Factor Beta

Using in situ hybridization, we investigated the expression of mRNA for interleukin-1 beta (IL1 beta), interleukin-6 (IL6), and transforming growth factor-beta-1 (TGF beta 1) in sections of developing bone in human osteophytes. The expression was related to the cellular activity of alkaline phosphatase to aid in the identification of pre-osteoblast populations. IL1 beta mRNA was localized in active osteoblasts within distinct areas of intramembranous ossification. However, the expression was sporadic and appeared to occur at a specific stage of the osteoblast life cycle. There was no IL1 beta mRNA expression in any cell types during endochondral ossification. IL6 mRNA expression was located within pre-osteoblasts and in newly differentiated and matrix-secreting osteoblasts; expression was absent or reduced in flattened, inactive osteoblasts. Weak or no IL6 expression was observed in chondroblasts and chondrocytes, respectively. However, there was a close association between IL6 mRNA expression and the differentiation of mesenchymal cells into osteoblasts. TGF beta 1 expression was localized to osteoblasts apposed to bone or cartilage matrix; the intensity of expression correlated with matrix secretion. Chondroblasts and chondrocytes expressed lower but significant levels of TGF beta 1 mRNA; the expression was lost with the progression to calcifying cartilage. The three cytokines studied were differentially expressed both temporally and spatially, suggesting different roles for each in osteoblast and chondrocyte function.

scholarly journals Coordinated changes in hepatic amino acid metabolism and endocrine signals support hepatic glucose production during fetal hypoglycemia

2015 ◽  
Vol 308 (4) ◽  
pp. E306-E314 ◽  
Author(s):  
Satya S. Houin ◽  
Paul J. Rozance ◽  
Laura D. Brown ◽  
William W. Hay ◽  
Randall B. Wilkening ◽  
...  
Keyword(s):  
Fetal Liver ◽  
Hepatic Glucose Production ◽  
Plasma Concentrations ◽  
Glucose Production ◽  
Late Gestation ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Hepatic Glucose ◽  
Molar Percent ◽  
Glucose Output

Reduced fetal glucose supply, induced experimentally or as a result of placental insufficiency, produces an early activation of fetal glucose production. The mechanisms and substrates used to fuel this increased glucose production rate remain unknown. We hypothesized that in response to hypoglycemia, induced experimentally with maternal insulin infusion, the fetal liver would increase uptake of lactate and amino acids (AA), which would combine with hormonal signals to support hepatic glucose production. To test this hypothesis, metabolic studies were done in six late gestation fetal sheep to measure hepatic glucose and substrate flux before (basal) and after [days (d)1 and 4] the start of hypoglycemia. Maternal and fetal glucose concentrations decreased by 50% on d1 and d4 ( P < 0.05). The liver transitioned from net glucose uptake (basal, 5.1 ± 1.5 μmol/min) to output by d4 (2.8 ± 1.4 μmol/min; P < 0.05 vs. basal). The [U-13C]glucose tracer molar percent excess ratio across the liver decreased over the same period (basal: 0.98 ± 0.01, vs. d4: 0.89 ± 0.01, P < 0.05). Total hepatic AA uptake, but not lactate or pyruvate uptake, increased by threefold on d1 ( P < 0.05) and remained elevated throughout the study. This AA uptake was driven largely by decreased glutamate output and increased glycine uptake. Fetal plasma concentrations of insulin were 50% lower, while cortisol and glucagon concentrations increased 56 and 86% during hypoglycemia ( P < 0.05 for basal vs. d4). Thus increased hepatic AA uptake, rather than pyruvate or lactate uptake, and decreased fetal plasma insulin and increased cortisol and glucagon concentrations occur simultaneously with increased fetal hepatic glucose output in response to fetal hypoglycemia.

Maternal undernutrition during the first week after conception results in decreased expression of glucocorticoid receptor mRNA in the absence of GR exon 17 hypermethylation in the fetal pituitary in late gestation

2013 ◽  
Vol 4 (5) ◽  
pp. 391-401 ◽  
Author(s):  
S. Zhang ◽  
O. Williams-Wyss ◽  
S. M. MacLaughlin ◽  
S. K. Walker ◽  
D. O. Kleemann ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Mrna Expression ◽  
Hpa Axis ◽  
Early Embryo ◽  
Late Gestation ◽  
Control Group ◽  
Fetal Sheep ◽  
Maternal Undernutrition ◽  
Stress Responsiveness ◽  
Periconceptional Period

Exposure to maternal undernutrition during the periconceptional period results in an earlier prepartum activation of the fetal hypothalamo–pituitary–adrenal (HPA) axis and altered stress responsiveness in the offspring. It is not known whether such changes are a consequence of exposure of the oocyte and/or the early embryo to maternal undernutrition in the periconceptional period. We have compared the effects of ‘periconceptional’ undernutrition (PCUN: maternal undernutrition imposed from at least 45 days before until 6 days after conception), and ‘early preimplantation’ undernutrition (PIUN: maternal undernutrition imposed for only 6 days after conception) on the expression of genes in the fetal anterior pituitary that regulate adrenal growth and steroidogenesis, proopiomelanorcortin (POMC), prohormone convertase 1 (PC1), 11β-hydroxysteroid dehydrogenase type 1 and 2 (11βHSD1 and 2) and the glucocorticoid receptor (GR) in fetal sheep at 136–138 days of gestation. Pituitary GR mRNA expression was significantly lower in the PCUN and PIUN groups in both singletons and twins compared with controls, although this suppression of GR expression was not associated with hypermethylation of the exon 17 region of the GR gene. In twin fetuses, the pituitary 11βHSD1 mRNA expression was significantly higher in the PIUN group compared with the PCUN but not the control group. Thus, exposure of the single or twin embryo to maternal undernutrition for only 1 week after conception is sufficient to cause a suppression of the pituitary GR expression in late gestation. These changes may contribute to the increased stress responsiveness of the HPA axis in the offspring after exposure to poor nutrition during the periconceptional period.

Increased lung prolyl hydroxylase and decreased glucocorticoid receptor are related to decreased surfactant protein in the growth-restricted sheep fetus

2015 ◽  
Vol 309 (1) ◽  
pp. L84-L97 ◽  
Author(s):  
Sandra Orgeig ◽  
Erin V. McGillick ◽  
Kimberley J. Botting ◽  
Song Zhang ◽  
I. Caroline McMillen ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Transforming Growth Factor ◽  
Acute Hypoxia ◽  
Fetal Lung ◽  
Surfactant Protein ◽  
Prolyl Hydroxylase ◽  
Fetal Sheep ◽  
Chronic Hypoxemia ◽  
Hypoxia Signaling

Experimental placental restriction (PR) by carunclectomy in fetal sheep results in intrauterine growth restriction (IUGR), chronic hypoxemia, increased plasma cortisol, and decreased lung surfactant protein (SP) expression. The mechanisms responsible for decreased SP expression are unknown but may involve decreased glucocorticoid (GC) action or changes in hypoxia signaling. Endometrial caruncles were removed from nonpregnant ewes to induce PR. Lungs were collected from control and PR fetuses at 130–135 ( n = 19) and 139–145 ( n = 28) days of gestation. qRT-PCR and Western blotting were used to quantify lung mRNA and protein expression, respectively, of molecular regulators and downstream targets of the GC and hypoxia-signaling pathways. We confirmed a decrease in SP-A, -B, and -C, but not SP-D, mRNA expression in PR fetuses at both ages. There was a net downregulation of GC signaling with a reduction in GC receptor (GR)-α and -β protein expression and a decrease in the cofactor, GATA-6. GC-responsive genes including transforming growth factor-β1, IL-1β, and β2-adrenergic receptor were not stimulated. Prolyl hydroxylase domain ( PHD) 2 mRNA and protein and PHD3 mRNA expression increased with a concomitant increase in hypoxia-inducible factor-1α ( HIF-1α) and HIF-1β mRNA expression. There was an increase in mRNA expression of several, but not all, hypoxia-responsive genes. Hence, both GC and hypoxia signaling may contribute to reduced SP expression. Although acute hypoxia normally inactivates PHDs, chronic hypoxemia in the PR fetus increased PHD abundance, which normally prevents HIF signaling. This may represent a mechanism by which chronic hypoxemia contributes to the decrease in SP production in the IUGR fetal lung.

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