scholarly journals Overexpression of Gly56/Gly80/Gly81-Mutant Insulin-Like Growth Factor-Binding Protein-3 in Transgenic Mice

Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1523-1531 ◽  
Author(s):  
Josef V. Silha ◽  
Yaoting Gui ◽  
Suresh Mishra ◽  
Arnold Leckstrom ◽  
Pinchas Cohen ◽  
...  
Keyword(s):  
Binding Protein ◽  
Serum Levels ◽  
Nuclear Antigen ◽  
Mouse Strains ◽  
Wild Type ◽  
Igf I ◽  
Independent Effects ◽  
Igfbp 3

IGF-independent effects of IGF-binding protein-3 (IGFBP-3) have been demonstrated in vitro; however, the physiological significance of these effects in vivo is unclear. We generated two transgenic (Tg) mouse strains that overexpress a human Gly56/Gly80/Gly81-mutant IGFBP-3 cDNA. This mutant has a markedly reduced affinity for the IGFs, but retains the IGF-independent effects. Serum levels of mutant IGFBP-3 were 156 ± 12 and 400 ± 24 ng/ml in hemizygous mice of strains 5005 and 5012, respectively. When Tg and wild-type mice were compared, there was no reduction in birth weight, litter size, or postnatal growth. Despite differences in transgene expression in various tissues, relative organ weight was similar in Tg and wild-type mice, with exception of brain, where a modest reduction in brain weight was observed in the high-expressing 5012 lineage. There was also a significant reduction in proliferating cell nuclear antigen-staining cells observed in the periventricular region of the developing brain in embryonic d 18 Tg embryos. In the higher expressing 5012 Tg strain, IGF-I and murine IGFBP-3 levels, marker of GH action were increased. Furthermore, there was a positive correlation between mutant IGFBP-3 levels and IGF-I levels and between mutant IGFBP-3 levels and murine IGFBP-3 (P = 0.002 and P < 0.001, respectively). These data indicate that overexpression of mutant IGFBP-3 is not associated with growth retardation. The higher levels of IGF-I and murine IGFBP-3 in the 5012 Tg strain suggest that the growth inhibitory effect of mutant IGFBP-3 may be compensated for by other mechanisms.

Phenotypic Manifestations of Insulin-Like Growth Factor-Binding Protein-3 Overexpression in Transgenic Mice*

Endocrinology ◽  
2001 ◽  
Vol 142 (5) ◽  
pp. 1958-1967 ◽  
Author(s):  
Tomislav Modric ◽  
Josef V. Silha ◽  
Zengdun Shi ◽  
Yaoting Gui ◽  
Adisak Suwanichkul ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Phosphoglycerate Kinase ◽  
Serum Levels ◽  
Postnatal Growth ◽  
Insulin Like Growth Factor ◽  
Liver Size ◽  
Igf I ◽  
Igfbp 3

Abstract In cell culture systems insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) can both enhance and inhibit IGF-I action. To investigate the biological role of IGFBP-3 in vivo, transgenic (Tg) mice that constitutively overexpress the human IGFBP-3 complementary DNA (cDNA) driven by the mouse phosphoglycerate kinase I (PGK) and the cytomegalovirus (CMV) promoters were examined. Serum levels of human IGFBP-3 in CMVBP-3 and PGKBP-3 Tg mice were 4.7 and 5.8μ g/ml, respectively and total IGFBP-3 was increased 4.9- and 7.7-fold compared with that in wild-type (Wt) mice. In PGKBP-3 Tg mice the levels of transgene expression were similar in all tissues. Although CMVBP-3 mice demonstrated similar levels of expression of the transgene as PGKBP-3 mice in most tissues, markedly elevated expression was apparent in the kidney and heart. The transgene-derived IGFBP-3 circulated as a 150-kDa ternary complex, and serum IGF-I levels were elevated 1.9- to 2.8-fold in Tg mice compared with Wt mice. A significant reduction in birth weight of approximately 10% and a modest reduction in litter size were apparent in both Tg strains. Early postnatal growth, as assessed by both body weight and length, was significantly reduced in Tg mice compared with Wt mice. This was more marked in PGKBP-3 than in CMVBP-3 mice, who demonstrated a propensity to adiposity after weaning. The relative organ weights of brain and kidney were reduced in both Tg strains, whereas liver size and epididymal fat were significantly increased in CMVBP-3, but not PGKBP-3, mice. Our data indicate that overexpression of IGFBP-3 is associated with modest intrauterine and postnatal growth retardation despite elevated circulating IGF-I levels.

scholarly journals Cubitus interruptus Requires DrosophilaCREB-Binding Protein To Activate wingless Expression in theDrosophila Embryo

2000 ◽  
Vol 20 (5) ◽  
pp. 1616-1625 ◽  
Author(s):  
Yang Chen ◽  
R. H. Goodman ◽  
Sarah M. Smolik
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Binding Protein ◽  
Point Mutations ◽  
Creb Binding Protein ◽  
Wild Type ◽  
Interaction Domain ◽  
Cubitus Interruptus

ABSTRACT CREB-binding protein (CBP) serves as a transcriptional coactivator in multiple signal transduction pathways. The Drosophilahomologue of CBP, dCBP, interacts with the transcription factors Cubitus interruptus (CI), MAD, and Dorsal (DL) and functions as a coactivator in several signaling pathways during Drosophiladevelopment, including the hedgehog (hh),decapentaplegic (dpp), and Tollpathways. Although dCBP is required for the expression of thehh target genes, wingless (wg) andpatched (ptc) in vivo, and potentiatesci-mediated transcriptional activation in vitro, it is not known that ci absolutely requires dCBP for its activity. We used a yeast genetic screen to identify several ci point mutations that disrupt CI-dCBP interactions. These mutant proteins are unable to transactivate a reporter gene regulated by cibinding sites and have a lower dCBP-stimulated activity than wild-type CI. When expressed exogenously in embryos, the CI point mutants cannot activate endogenous wg expression. Furthermore, a CI mutant protein that lacks the entire dCBP interaction domain functions as a negative competitor for wild-type CI activity, and the expression of dCBP antisense RNAs can suppress CI transactivation in Kc cells. Taken together, our data suggest that dCBP function is necessary forci-mediated transactivation of wg duringDrosophila embryogenesis.

Serum levels of insulin-like growth factors (IGF-I and IGF-II) and their binding protein (IGFBP-3) are not elevated in pancreatic cancer

1997 ◽  
Vol 22 (2) ◽  
pp. 95-100
Author(s):  
James D. Evans ◽  
Margaret C. Eggo ◽  
Ian A. Donovan ◽  
Simon R. Bramhall ◽  
John P. Neoptolemos
Keyword(s):  
Pancreatic Cancer ◽  
Growth Factors ◽  
Binding Protein ◽  
Serum Levels ◽  
Igf I ◽  
Igfbp 3 ◽  
Insulin Like Growth Factors

Changes induced by non-enzymatic glycosylation of IGF-binding protein-3: effects on its binding properties and on its modulatory effect on IGF-I mitogenic action

1995 ◽  
Vol 144 (1) ◽  
pp. 119-126 ◽  
Author(s):  
A M Cortizo ◽  
J J Gagliardino
Keyword(s):  
Binding Protein ◽  
Mitogenic Activity ◽  
Dependent Manner ◽  
Binding Properties ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Enzymatic Glycosylation ◽  
Igfbp 3

Abstract The aim of this study was to demonstrate the feasibility of in vitro non-enzymatic glycosylation of IGF-binding protein-3 (IGFBP-3) and whether this process affects its binding properties and its modulatory effect on IGF-I mitogenic activity. Swiss 3T3 fibroblasts were cultured and the IGFBP-3 released into the medium (CM) glycated with either labelled or unlabelled glucose. Parallel glycation studies were performed using standard human IGFBP-3. Both species of IGFBP-3 became effectively glycated in a dose-dependent manner. Glycated IGFBP-3 bound larger amounts of 125I-labelled IGF-I than its non-glycated form. According to Scatchard analysis this effect might be due to an increase in the number of binding sites of the IGFBP-3 molecule rather than to changes in its affinity constants, which remain unchanged. Preincubation of fibroblasts with CM containing IGFBP-3 for 16 h before the addition of IGF-I enhanced the stimulatory effect of the hormone on thymidine incorporation into cell DNA. This potentiation was blunted when in vitro glycated instead of non-glycated IGFBP-3 was employed. These results provide further evidence of the in vitro glycation of IGFBP-3 and demonstrate that this process affects both its binding properties and its enhancing effect on IGF-I mitogenic activity. These changes may explain, at least partially, the development of many alterations observed in poorly controlled diabetic patients. Journal of Endocrinology (1995) 144, 119–126

scholarly journals Serum IGF-I, IGFBP-3, and matrix metalloproteinase-7 levels and acquired chemo-resistance in advanced colorectal cancer

2009 ◽  
Vol 16 (1) ◽  
pp. 311-317 ◽  
Author(s):  
Rosa Gallego ◽  
Jordi Codony-Servat ◽  
Xabier García-Albéniz ◽  
Enric Carcereny ◽  
Raquel Longarón ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Matrix Metalloproteinase ◽  
Progressive Disease ◽  
Advanced Colorectal Cancer ◽  
Serum Levels ◽  
Chemotherapy Treatment ◽  
Igf I ◽  
Matrix Metalloproteinase 7 ◽  
Igfbp 3

Insulin-like growth factor-I (IGF-I) is thought to have antiapoptotic and mitogenic properties in colorectal cancer, whereas IGF-binding protein-3 (IGFBP-3) seems to exert a pro-apoptotic effect. Additionally, matrix metalloproteinase-7 (MMP-7), an enzyme with in vitro ability to degrade IGFBP-3, has been shown to be a prognostic factor in advanced colorectal cancer (ACRC). We studied whether chemotherapy treatment for ACRC modulates IGF-I, IGFBP-3, and MMP-7 serum levels. In 41 patients undergoing first-line therapy for ACRC, serum levels of IGF-I, IGFBP-3, and MMP-7 were measured with immunoassays at baseline and every 3 months until progressive disease, or a maximum of five determinations, during a chemotherapy regimen of either FOLFOX or FOLFIRI therapies. Associations were assessed for paired samples, using t-test or Wilcoxon ranks test depending on normality of the variable, verified with Shapiro-Wilk test. An average of four extractions (range 3–5) were done, for a total of 157 determinations. Mean pretreatment values of IGF-I, IGFBP-3, and MMP-7 were 83 (95% CI, 73–92) ng/ml, 2372 (95% CI, 2121–2623) ng/ml, and 10.6 (95% CI, 7.21–13.98) ng/ml respectively. No significant changes in IGF-I were found, but a significant increase in IGFBP-3 serum concentrations was observed during or after chemotherapy treatment without progressive disease, compared with basal levels (P<0.001). A significant decrease in IGFBP-3 to 1983 ng/ml (95% CI, 1675–2292) and a significant increase in MMP-7 levels to 14.6 (7.6–21.7) ng/ml were observed at progression of disease compared with baseline and treatment levels (P<0.001). This study shows that IGFBP-3 and MMP-7 serum levels change during chemotherapy treatment. The increased MMP-7 levels at disease progression support the hypothesis that this protease could play a role in acquired resistance by degrading IGFBP-3.

Serum free IGF-I during a hyperinsulinemic clamp following 3 days of administration of IGF-I vs. saline.

1997 ◽  
Vol 273 (3) ◽  
pp. E507 ◽  
Author(s):  
J Frystyk ◽  
M Hussain ◽  
C Skjaerbaek ◽  
O Schmitz ◽  
J S Christiansen ◽  
...  
Keyword(s):  
Subcutaneous Administration ◽  
Serum Levels ◽  
Fasting Serum ◽  
Short Term ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Randomized Crossover Study ◽  
Igfbp 3

In a randomized crossover study in eight healthy subjects, we compared the effect of 3 days of continuous subcutaneous administration of insulin-like growth factor I (IGF-I; 10 micrograms.kg-1.h-1) and saline on fasting serum levels of free IGF-I, total (extractable) IGF-I, and IGF-binding protein (IGFBP)-1 and -3. On the 3rd day a hyperinsulinemic (euglycemic and hypoglycemic) clamp was performed. When preclamp (baseline) levels were compared after 3 days, IGF-I administration had increased total IGF-I from 225 +/- 21 (means +/- SE) to 1,003 +/- 46 micrograms/l (P < 0.0001), free IGF-I from 0.5 +/- 0.2 to 10.4 +/- 1.7 micrograms/l (P < 0.001), IGFBP-3 from 2,908 +/- 148 to 3,591 +/- 179 micrograms/l (P < 0.01), and IGFBP-1 from 7.6 +/- 3.8 to 19.6 +/- 2.5 micrograms/l (P < 0.01). During the clamp, levels of free IGF-I increased gradually from baseline to 1.0 +/- 0.3 micrograms/l (saline; P < 0.01) and to 19.6 +/- 4.7 micrograms/l (IGF-I; P < 0.005). Concomitantly, levels of IGFBP-1 decreased gradually from baseline to 4.1 +/- 2.3 micrograms/l (saline; P < 0.0005) and to 4.6 +/- 1.8 micrograms/l (IGF-I; P < 0.0001). Total IGF-I exhibited minor changes only during the clamp (P < 0.05), and IGFBP-3 was unchanged. In conclusion, administration of IGF-I increased total IGF-I about fourfold, whereas free IGF-I increased 20-fold. Noteworthily, in both situations a further twofold increase in free IGF-I was observed during the hyperinsulinemic clamp, concomitant with a decrease in IGFBP-1. This supports the hypothesis that IGFBP-1 is important in the short-term regulation of free IGF-I in vivo.

scholarly journals Blockade of Sphingosine 1-Phosphate Receptor 2 Signaling Attenuates High-Fat Diet-Induced Adipocyte Hypertrophy and Systemic Glucose Intolerance in Mice

Endocrinology ◽  
2016 ◽  
Vol 157 (5) ◽  
pp. 1839-1851 ◽  
Author(s):  
Yoshihiko Kitada ◽  
Kazuo Kajita ◽  
Koichiro Taguchi ◽  
Ichiro Mori ◽  
Masahiro Yamauchi ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Adipogenic Differentiation ◽  
Nuclear Antigen ◽  
Wild Type ◽  
High Fat ◽  
Insulin Tolerance ◽  
Sphingosine 1 Phosphate

Abstract Sphingosine 1-phosphate (S1P) is known to regulate insulin resistance in hepatocytes, skeletal muscle cells, and pancreatic β-cells. Among its 5 cognate receptors (S1pr1–S1pr5), S1P seems to counteract insulin signaling and confer insulin resistance via S1pr2 in these cells. S1P may also regulate insulin resistance in adipocytes, but the S1pr subtype(s) involved remains unknown. Here, we investigated systemic glucose/insulin tolerance and phenotypes of epididymal adipocytes in high-fat diet (HFD)-fed wild-type and S1pr2-deficient (S1pr2−/−) mice. Adult S1pr2−/− mice displayed smaller body/epididymal fat tissue weights, but the differences became negligible after 4 weeks with HFD. However, HFD-fed S1pr2−/− mice displayed better scores in glucose/insulin tolerance tests and had smaller epididymal adipocytes that expressed higher levels of proliferating cell nuclear antigen than wild-type mice. Next, proliferation/differentiation of 3T3-L1 and 3T3-F442A preadipocytes were examined in the presence of various S1pr antagonists: JTE-013 (S1pr2 antagonist), VPC-23019 (S1pr1/S1pr3 antagonist), and CYM-50358 (S1pr4 antagonist). S1P or JTE-013 treatment of 3T3-L1 preadipocytes potently activated their proliferation and Erk phosphorylation, whereas VPC-23019 inhibited both of these processes, and CYM-50358 had no effects. In contrast, S1P or JTE-013 treatment inhibited adipogenic differentiation of 3T3-F442A preadipocytes, whereas VPC-23019 activated it. The small interfering RNA knockdown of S1pr2 promoted proliferation and inhibited differentiation of 3T3-F442A preadipocytes, whereas that of S1pr1 acted oppositely. Moreover, oral JTE-013 administration improved glucose tolerance/insulin sensitivity in ob/ob mice. Taken together, S1pr2 blockade induced proliferation but suppressed differentiation of (pre)adipocytes both in vivo and in vitro, highlighting a novel therapeutic approach for obesity/type 2 diabetes.

No evidence for reduced spontaneous or growth-hormone-stimulated serum levels of insulin-like growth factor (IGF)-I, IGF-II or IGF binding protein 3 in women with spinal osteoporosis

1994 ◽  
Vol 131 (2) ◽  
pp. 150-155 ◽  
Author(s):  
M Kassem ◽  
K Brixen ◽  
W Blum ◽  
L Mosekilde ◽  
EF Eriksen
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Binding Protein ◽  
Serum Levels ◽  
Insulin Like Growth Factor ◽  
Spinal Osteoporosis ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

Kassem M, Brixen K, Blum W, Mosekilde L, Eriksen EF. No evidence for reduced spontaneous or growth-hormone-stimulated serum levels of insulin-like growth factor (IGF)-I, IGF-II or IGF binding protein 3 in women with spinal osteoporosis. Eur J Endocrinol 1994;131:150–5. ISSN 0804–4643 To test the hypothesis that a dysfunctional growth hormone (GH)–insulin-like growth factor (IGF) axis may play a role in the pathogenesis of osteoporosis, we compared the levels of IGF-I, IGF-II and IGF binding protein 3 (IGFBP-3) in 15 women with spinal osteoporosis (i.e. at least one non-traumatic vertebral fracture) and 15 normal age-matched women. Furthermore, the response to 3 days' treatment with recombinant human GH (r-hGH) (0.2 IU kg−1·day−1) was determined. The basal levels of IGF-I, IGF-II and IGFBP-3 were similar in patients and controls (mean ± sem): IGF-I, 16.5 ± 1.3 versus 16.0 ± 1.3 nmol/l (NS); IGF-II, 79.9 ± 3.6 versus 72.5 ± 4.1 nmol/l (NS); and IGFBP-3, 125.7 ± 6.5 versus 130.3 ± 7.8 nmol/l (NS). Stimulation with r-hGH elicited increased levels of IGF-I, IGF-II and IGFBP-3 within both groups (p < 0.001). The maximal values expressed as a percentage of baseline were: IGF-I, 341 ± 26% versus 369 ± 22%, IGF-II, 125 ± 4% versus 119 ± 5%, IGFBP-3, 141 ± 5% versus 147 ± 7% in osteoporotic patients and controls, respectively. No significant differences were observed between patients and controls in either their maximal response or in the area under the response curves. Our results do not support the hypothesis of a dysfunctional GH–IGF axis in women with spinal osteoporosis. Kim Brixen, University Department of Endocrinology and Metabolism, Aarhus Amtssygehus, Tage-Hansens gade 2, DK-8000 Aarhus C, Denmark

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