scholarly journals Differential regulation of Igf1 and Igf2 mRNA levels in tilapia hepatocytes: effects of insulin and cortisol on GH sensitivity

2011 ◽  
Vol 211 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Andrew L Pierce ◽  
Jason P Breves ◽  
Shunsuke Moriyama ◽  
Tetsuya Hirano ◽  
E Gordon Grau
Keyword(s):  
Growth And Development ◽  
Mrna Level ◽  
Differential Regulation ◽  
Postnatal Life ◽  
Mrna Levels ◽  
Primary Cultured Hepatocytes ◽  
Mammalian Liver ◽  
Growth Promoting ◽  
Stimulation Of

Igf1 and Igf2 stimulate growth and development of vertebrates. In mammals, liver-derived endocrine Igf1 mediates the growth promoting effects of GH during postnatal life, whereas Igf2 stimulates placental and fetal growth and is not regulated by GH. Insulin enhances Igf1 production by the mammalian liver directly, and by increasing hepatocyte sensitivity to GH. We examined the regulation ofigf1andigf2mRNA levels by GH, insulin, and cortisol, and the effects of insulin and cortisol on GH sensitivity in primary cultured hepatocytes of tilapia, a cichlid teleost. GH increased mRNA levels of bothigf1andigf2in a concentration-related and biphasic manner over the physiological range, with a greater effect onigf2mRNA level. Insulin increased basaligf2mRNA level, and strongly increased GH-stimulatedigf2mRNA level, but slightly reduced basaligf1mRNA level and did not affect GH-stimulatedigf1mRNA level. Cortisol inhibited GH stimulation ofigf1, but increased GH stimulation ofigf2mRNA level. The synergistic effect of insulin and GH onigf2mRNA level was confirmedin vivo. These results indicate that insulin and cortisol differentially modulate the response ofigf1andigf2mRNA to GH in tilapia hepatocytes, and suggest that the regulation of liver Igf2 production differs between fish and mammals. Regulation of liver Igf2 production in fish appears to be similar to regulation of liver Igf1 production in mammals.

scholarly journals Metabolic hormones regulate basal and growth hormone-dependent igf2 mRNA level in primary cultured coho salmon hepatocytes: effects of insulin, glucagon, dexamethasone, and triiodothyronine

2009 ◽  
Vol 204 (3) ◽  
pp. 331-339 ◽  
Author(s):  
A L Pierce ◽  
J T Dickey ◽  
L Felli ◽  
P Swanson ◽  
W W Dickhoff
Keyword(s):  
Growth Hormone ◽  
Coho Salmon ◽  
Mrna Level ◽  
Postnatal Growth ◽  
Mrna Levels ◽  
Growth Physiology ◽  
Metabolic Hormones ◽  
Synergistic Regulation ◽  
Growth Promoting ◽  
Stimulation Of

Igf1 and Igf2 stimulate growth and development of vertebrates. Circulating Igfs are produced by the liver. In mammals, Igf1 mediates the postnatal growth-promoting effects of growth hormone (Gh), whereas Igf2 stimulates fetal and placental growth. Hepatic Igf2 production is not regulated by Gh in mammals. Little is known about the regulation of hepatic Igf2 production in nonmammalian vertebrates. We examined the regulation of igf2 mRNA level by metabolic hormones in primary cultured coho salmon hepatocytes. Gh, insulin, the glucocorticoid agonist dexamethasone (Dex), and glucagon increased igf2 mRNA levels, whereas triiodothyronine (T3) decreased igf2 mRNA levels. Gh stimulated igf2 mRNA at physiological concentrations (0.25×10−9 M and above). Insulin strongly enhanced Gh stimulation of igf2 at low physiological concentrations (10−11 M and above), and increased basal igf2 (10−8 M and above). Dex stimulated basal igf2 at concentrations comparable to those of stressed circulating cortisol (10−8 M and above). Glucagon stimulated basal and Gh-stimulated igf2 at supraphysiological concentrations (10−7 M and above), whereas T3 suppressed basal and Gh-stimulated igf2 at the single concentration tested (10−7 M). These results show that igf2 mRNA level is highly regulated in salmon hepatocytes, suggesting that liver-derived Igf2 plays a significant role in salmon growth physiology. The synergistic regulation of igf2 by insulin and Gh in salmon hepatocytes is similar to the regulation of hepatic Igf1 production in mammals.

scholarly journals Ribonucleic acid stimulation of mammalian liver nuclear-envelope nucleoside triphosphatase. A possible enzymic marker for the nuclear envelope

1977 ◽  
Vol 162 (3) ◽  
pp. 671-679 ◽  
Author(s):  
P S Agutter ◽  
J R Harris ◽  
I Stevenson
Keyword(s):  
Nuclear Envelope ◽  
Specific Activity ◽  
Assay Medium ◽  
Exogenous Rna ◽  
Mammalian Liver ◽  
High Concentrations ◽  
Enzymic Marker ◽  
Stimulation Of ◽  
Nucleoside Triphosphatase

1. The specific activity of rat and pig liver nuclear-envelope nucleoside triphosphatase (EC 3.6.1.3) decreases when the system is depleted of RNA. The activity can be restored by adding high concentrations of yeast RNA to the assay medium. 2. Exogenous RNA also increases the activity of the enzyme in control envelopes (not RNA-depleted). The effect appears to be largely specific for poly(A) and poly(G); it is not stimulated by rRNA or tRNA preparations, ribonuclease-hydrolysed RNA, AMP, or double- or single-stranded DNA. 3. Inhibitors of the enzyme, in concentrations at which half-maximal inhibition of the enzyme is achieved, do not affect the percentage stimulation of the enzyme by yeast RNA. 4. The simulation is abolished by the inclusion of 150 mM-KCl or -NaCl in the assay medium, but not by increasing the assay pH to 8.5. 5. The results are discussed in the light of the possible role of the nucleoside triphosphatase in vivo in nucleo-cytoplasmic ribonucleoprotein translocation. 6. It is proposed that poly(G)-stimulated Mg2+-activated adenosine triphosphatase activity should be adopted as an enzymic marker for the nuclear envelope.

scholarly journals Regulation of angiopoietin-like protein 4/fasting-induced adipose factor (Angptl4/FIAF) expression in mouse white adipose tissue and 3T3-L1 adipocytes

2008 ◽  
Vol 100 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Sarah Dutton ◽  
Paul Trayhurn
Keyword(s):  
Skeletal Muscle ◽  
Cell Culture ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Culture Medium ◽  
Mrna Level ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Before And After ◽  
Stimulation Of

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.

Fatty-acid synthase activity and mRNA level in hypertrophic type II cells from silica-treated rats

1994 ◽  
Vol 267 (2) ◽  
pp. L128-L136
Author(s):  
J. Rami ◽  
W. Stenzel ◽  
S. M. Sasic ◽  
C. Puel-M'Rini ◽  
J. P. Besombes ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Mrna Level ◽  
Type Ii Cells ◽  
Mrna Levels ◽  
Type Ii ◽  
Maximum Increase

Silica instillation causes a massive increase in lung surfactant. Two populations of type II pneumocytes can be isolated from rats administered silica by intratracheal injection: type IIA cells similar to type II cells from normal rats and type IIB cells, which are larger and contain elevated levels of surfactant protein A and phospholipid. Activities of choline-phosphate cytidylyltransferase, a rate-regulatory enzyme in phosphatidylcholine biosynthesis, and fatty-acid synthase (FAS) are increased in type IIB cells isolated from rats 14 days after silica injection. In the present study, we examined the increase in FAS and cytidylyltransferase activities in type IIB cells as a function of time after silica administration. FAS activity increased rapidly, was approximately threefold elevated 1 day after silica administration and has reached close to the maximum increase by 3 days. Cytidylyltransferase activity was not increased on day 1, was significantly increased on day 3 but was not maximally increased until day 7. Inhibition of de novo fatty-acid biosynthesis, by in vivo injection of hydroxycitric acid and inclusion of agaric acid in the type II cell culture medium, abolished the increase in cytidylyltransferase activity on day 3 but not FAS and had no effect on activities of two other enzymes of phospholipid synthesis. FAS mRNA levels were not increased in type IIB cells isolated 1-14 days after silica injection. These data show that the increase in FAS activity in type IIB cells is an early response to silica, that it mediates the increase in cytidylyltransferase activity, and that it is not due to enhanced FAS gene expression.

Cellular distribution of insulin-like growth factor binding protein mRNAs and peptides during rat lung development

1997 ◽  
Vol 155 (2) ◽  
pp. 313-327 ◽  
Author(s):  
LD Wallen ◽  
W Myint ◽  
K Nygard ◽  
S Shimasaki ◽  
DR Clemmons ◽  
...  
Keyword(s):  
Airway Epithelium ◽  
Lung Development ◽  
Fetal Lung ◽  
Northern Analysis ◽  
Postnatal Life ◽  
Mrna Levels ◽  
Igf Binding Proteins ◽  
Paracrine Factors ◽  
Igfbp 3

A role for IGF binding proteins (IGFBPs) in lung development is suggested by the identification of IGFBPs in lung tissue and production of IGFBPs by fetal lung cells in culture. To characterize the expression of IGFBPs during lung development in the rat in vivo (16 days gestation through adulthood), the expression of IGFBP mRNAs (IGFBP-1 to IGFBP-6) was examined by Northern analysis and in situ hybridization, and IGFBP peptides (IGFBP-2, IGFBP-3, and IGFBP-5) were localized by immunohistochemistry. IGFBP-1 mRNA was not detectable. IGFBP-2 mRNA (1.8 kb) was expressed in both fetal and postnatal life with peak expression during the fetal pseudoglandular stage. IGFBP-2 mRNA was localized mainly to airway epithelium. IGFBP-3 mRNA (2.4 kb) was maximally expressed postnatally in the saccular stage of lung development; it was identified in airway epithelium and interstitium in the fetal lung, but predominantly in airway epithelium after birth. IGFBP-4 (2.6 kb) and IGFBP-5 (6.0 kb) mRNA levels were maximal after birth, from 3 to 21 days postnatal (saccular and alveolar stage). IGFBP-4 mRNA was localized primarily to the interstitium and blood vessels early in development, but was abundant in airway epithelium in the adult. IGFBP-5 mRNA was most abundant in the airway epithelium. IGFBP-3, IGFBP-4, IGFBP-5, and to a lesser extent IGFBP-6 were localized to the large cartilaginous airways in the adult. IGFBP-2, IGFBP-3, and IGFBP-5 peptides were distributed more widely than their respective mRNAs, with a temporal pattern of immunoreactivity following that of their mRNAs. Maximal staining was noted in airway epithelium for IGFBP-2 in the newborn, for IGFBP-3 in the saccular stage (newborn to 3 days postnatal), and for IGFBP-5 in the alveolar stage (5 to 21 days postnatal). Our studies demonstrate that IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 are synthesized and distributed in spatially and temporally different patterns in the developing lung. The widespread distribution of IGFBP immunoreactivity compared with their respective mRNAs suggests that IGFBPs are important paracrine factors in the regulation of IGF action in the developing lung.

MUSCLE-INDUCED PATELLOFEMORAL JOINT LOADING RAPIDLY AFFECTS CARTILAGE mRNA LEVELS IN A SITE SPECIFIC MANNER

2004 ◽  
Vol 08 (01) ◽  
pp. 1-12 ◽  
Author(s):  
Andrea L. Clark ◽  
Linda Mills ◽  
David A Hart ◽  
Walter Herzog
Keyword(s):  
Articular Cartilage ◽  
Mechanical Loading ◽  
Patellofemoral Joint ◽  
Mrna Level ◽  
Recovery Period ◽  
Cartilage Explants ◽  
Mrna Levels ◽  
Biological Responses

Mechanical loading of articular cartilage affects the synthesis and degradation of matrix macromolecules. Much of the work in this area has involved mechanical loading of articular cartilage explants or cells in vitro and assessing biological responses at the mRNA and protein levels. In this study, we developed a new experimental technique to load an intact patellofemoral joint in vivo using muscle stimulation. The articular cartilages were cyclically loaded for one hour in a repeatable and measurable manner. Cartilage was harvested from central and peripheral regions of the femoral groove and patella, either immediately after loading or after a three hour recovery period. Total RNA was isolated from the articular cartilage and biological responses were assessed on the mRNA level using the reverse transcriptase-polymerase chain reaction. Articular cartilage from intact patellofemoral joints demonstrated heterogeneity at the mRNA level for six of the genes assessed independent of the loading protocol. Cyclical loading of cartilage in its native environment led to alterations in mRNA levels for a subset of molecules when assessed immediately after the loading period. However, the increases in TIMP-1 and decreases in bFGF mRNA levels were transient; being present immediately after load application but not after a three hour recovery period.

scholarly journals Improvement Activity of 1-Deoxynojirimycin in the Growth of Dairy Goat Primary Mammary Epithelial Cell through Upregulating LEF-1 Expression

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Shengyue Ji ◽  
Ming Liu ◽  
Yuping Zhang ◽  
Hongfu Zhang
Keyword(s):  
Mammary Gland ◽  
Cell Growth ◽  
Epithelial Cell ◽  
Growth And Development ◽  
Mrna Level ◽  
Dairy Goat ◽  
Breast Epithelial Cell ◽  
Mrna Levels ◽  
Dairy Goats ◽  
Breast Epithelial

LEF-1/wnt10b is one of the most important signaling pathways regulating mammary gland growth and development and is also a potential target for molecular breeding. In this work, 1-deoxynojirimycin (DNJ), a natural alkaloid extracted from plant mulberry or microorganism, was found to have a positive activity in primary breast epithelial cell growth of dairy goats. The findings showed that, compared to the control, 6 μM DNJ in the DMEM/F12 medium in vitro greatly improved the density of dairy goat breast epithelial cell and significantly increased the LEF-1 mRNA level (P<0.01) and thus enhanced cell growth. In addition, DNJ displayed a similar function in alleviating the growth suppression of epithelial cell and the decrease of LEF-1 mRNA level resulting from lentiviral-mediated LEF-1 knockdown. Simultaneously, no significant change of the mRNA levels of IGF-1 and Fgf10, the other two key regulators in mammary gland growth and development, could be detected. Furthermore, the mammary duct of DNJ-fed mouse illustrated a better development accompanied with a higher LET-1 mRNA level than that of the control. In conclusion, DNJ could improve breast epithelial cell growth through upregulating LEF-1 expression, which supplied a new means in studying mammary gland growth and development.

μ Opioid Receptor Stimulates a Growth Promoting and Pro-Angiogenic Tumor Microenvironment by Transactivating VEGF Receptor-2/Flk-1.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3687-3687
Author(s):  
Elliot J. Stephenson ◽  
Humberto J. Martinez-Suarez ◽  
Mariya Farooqui ◽  
Debabrata Mukhopadhyay ◽  
Deborah A. Hughes ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Opioid Receptor ◽  
Calcium Release ◽  
Small Gtpase ◽  
Endothelial Cell Proliferation ◽  
Vegf Receptor ◽  
Growth Promoting ◽  
Stimulation Of

Abstract Like VEGF, morphine stimulates MAPK/ERK and Akt, leading to the promotion of angiogenesis via NO dependent signaling (Cancer Res62: 4491, 2002). Morphine acts via pertussis toxin (PT)-dependent G-protein coupled receptors (GPCRS), while VEGF acts via receptor tyrosine kinases (RTKs). We showed that PT-dependent GPCRs transactivate VEGF receptor-2/Flk1 via small GTPase RhoA (JBC277: 4679, 2002; JBC278:20738, 2003). Therefore, we hypothesized that morphine via the mu opioid receptor (MOR) transactivates Flk1 and promotes a pro-angiogenic microenvironment. Morphine-induced proliferation of human umbilical vein endothelial cells (HUVEC) was completely abrogated by Y-27632 (100 μM), a highly selective and potent inhibitor of Rho-associated protein kinases, suggesting the activation of Rho signaling by morphine. Addition of 1 μM morphine potentiated VEGF-induced (10 ng/ml) proliferation of HUVEC by 25%. We observed a 30% increase in intracellular calcium release after VEGF stimulation of HUVEC pre-incubated with morphine as compared to HUVEC pre-incubated with PBS, detected by a change in the fluorescence ratio of the Fura-2 AM dye. These findings show that morphine, via MOR and Rho signaling, transactivates Flk1 leading to the stimulation of calcium signaling and endothelial cell proliferation. To functionally corroborate our hypothesis, we used MOR knockout (MOR-KO) mice and injected them with MOR-replete T241 fibrosarcoma cells. T241 fibrosarcoma tumor growth in vivo showed appearance of palpable and measurable tumors 2 days earlier in wild type (wt) as compared to MOR-KO mice. Tumor growth and angiogenesis were decreased by 20–35% in MOR-KO mice as compared to wt littermates during 3 weeks of tumor growth. None of the MOR-KO showed signs of lung metastasis versus 40% wt mice with metastasis. Morphine (1.42 for the first 2 wks and 2.14 mg/Kg/day later, respectively) stimulated 20–35% tumor growth in wt, but not in MOR-KO mice. Western immunoblotting showed a 10-fold increase in the expression of phospho-Flk1 in morphine treated wt tumors as compared to PBS-treated wt mice. Morphine did not stimulate phospho-Flk1 expression in MOR-KO mice. Western analysis of immunoprecipitates obtained with α-MOR antibody showed the expression of Flk1 and phospho-Flk1 in wt, but were not expressed in MOR-KO tumors. Thus, MOR stimulates the transactivation of Flk1 in wt mice but not in MOR-KO. These in vitro and in vivo data using MOR-KO mice and the MOR agonist, morphine, show that MOR stimulates endothelial proliferation, angiogenesis and promotes tumor growth and metastasis directly as well as by transactivating Flk1 phosphorylation. We speculate that MOR is a critical component of the ‘angiogenic switch’, which regulates the pro-angiogenic and growth promoting tumor microenvironment. Thus, MOR provides a novel target for developing anti-angiogenic therapies.

scholarly journals Apolipoprotein CI overexpression is not a relevant strategy to block cholesteryl ester transfer protein (CETP) activity in CETP transgenic mice

2004 ◽  
Vol 385 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Thomas GAUTIER ◽  
David MASSON ◽  
Miek C. JONG ◽  
Jean-Paul PAIS DE BARROS ◽  
Linda DUVERNEUIL ◽  
...  
Keyword(s):  
Cholesteryl Ester ◽  
Cholesteryl Ester Transfer Protein ◽  
Mrna Level ◽  
Fold Increase ◽  
Receptor Activation ◽  
Liver X Receptor ◽  
Mrna Levels ◽  
Transfer Protein ◽  
Transfer Activity

ApoCI (apolipoprotein CI) is a potent inhibitor of plasma CETP [CE (cholesteryl ester) transfer protein]. The relevance of apoCI overexpression as a method for CETP blockade in vivo was addressed in the present study in CETPTg/apoCITg mice (mice expressing both human CETP and apoCI). Despite a significant reduction in specific CETP activity in CETPTg/apoCITg mice compared with CETPTg mice [transgenic mouse to human CETP; 46.8±11.1 versus 101.8±25.7 pmol·h−1·(μg of plasma CETP)−1 respectively; P<0.05], apoCI overexpression increased both the CETP mass concentration (3-fold increase; P<0.05) and the hepatic CETP mRNA level (4-fold increase, P<0.005), leading to an increase in total plasma CE transfer activity (by 39%, P<0.05). The ratio of apoB-containing lipoprotein to HDL (high-density lipoprotein) CE was 10-fold higher in CETPTg/apoCITg mice than in apoCITg mice (P<0.0005). It is proposed that the increased CETP expression in CETPTg/apoCITg mice is a direct consequence of liver X receptor activation in response to the accumulation of cholesterol-rich apoB-containing lipoproteins. In support of the latter view, hepatic mRNA levels of other liver X receptor-responsive genes [ABCG5 (ATP-binding cassette transporter GS) and SREBP-1c (sterol-regulatory-binding protein-1c)] were higher in CETPTg/apoCITg mice compared with CETPTg mice. In conclusion, overexpression of apoCI, while producing a significant inhibitory effect on specific CETP activity, does not represent a suitable method for decreasing total CE transfer activity in CETPTg/apoCITg mice, owing to an hyperlipidaemia-mediated effect on CETP gene expression.

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