Differential regulation of insulin-like growth factor binding protein-2 and -4 mRNA in muscle tissues and liver by diabetes or fasting

1994 ◽  
Vol 143 (2) ◽  
pp. 235-242 ◽  
Author(s):  
Y Chen ◽  
H J Arnqvist

Abstract The present study was undertaken to investigate the metabolic regulation of insulin-like growth factor binding proteins (IGFBPs) gene expression in muscles from diabetic or fasted rat. The messenger RNA (mRNA) levels for IGFBP-2 and -4 were analysed by solution hybridization in heart, skeletal and smooth muscle and liver from fasted (3 days) and refed (6, 12, 24, 72 h) rats and rats made diabetic with streptozotocin. In aortic intima-media, the mRNA levels for IGFBP-2 and -4 were decreased by diabetes or fasting and were restored gradually by refeeding. The response of IGFBP-4 mRNA to diabetes appeared two days after injection of streptozotocin, while a significant decrease of IGFBP-2 mRNA was found after a diabetes duration of two weeks. Both diabetes and fasting decreased IGFBP-4 mRNA levels in heart muscle and skeletal muscle and refeeding restored mRNA for IGFBP-4 to normal level. IGFBP-2 mRNA was undetectable in heart muscle and skeletal muscle. In liver IGFBP-4 mRNA was abundantly expressed. It was slightly but significantly decreased by fasting and approached normality with refeeding, while no change was found in diabetic liver. In contrast, liver IGFBP-2 mRNA was much lower in amount than IGF-I mRNA and IGFBP-4 mRNA and was sharply elevated by fasting, and decreased by refeeding. In conclusion, 1) both IGFBP-2 and -4 mRNA in various tissues are regulated by diabetes or fasting; 2) the mRNA for IGFBP-2 is metabolically regulated in a discordant, organ-specific manner. Journal of Endocrinology (1994) 143, 235–242

1998 ◽  
Vol 85 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Yasuhiro Kumei ◽  
Hitoyata Shimokawa ◽  
Hisako Katano ◽  
Hideo Akiyama ◽  
Masahiko Hirano ◽  
...  

Rat osteoblasts were cultured for 4 or 5 days during a Space Shuttle mission. After 20-h treatment with 1α,25-dihydroxyvitamin D3, conditioned media were harvested and cellular DNA and/or RNA were fixed on board. The insulin-like growth factor binding protein (IGF BP)-3 levels in the media were three- and tenfold higher than in ground controls on the fourth and fifth flight days, as quantitated by Western ligand blotting and radioimmunoassay, respectively. The increased IGF BP-3 protein levels correlated with two- to threefold elevation of IGF BP-3 mRNA levels, obtained by reverse transcription-polymerase chain reaction. The IGF BP-5 mRNA levels in flight cultures were 33–69% lower than in ground controls. The IGF BP-4 mRNA levels in flight cultures were 75% lower than in ground controls on the fifth day but were not different on the fourth day. The glucocorticoid receptor mRNA levels in flight cultures were increased by three- to eightfold on the fourth and fifth days compared with levels in ground controls. These data suggest potential mechanisms underlying spaceflight-induced osteopenia.


1990 ◽  
Vol 259 (1) ◽  
pp. E89-E95 ◽  
Author(s):  
D. L. DeVol ◽  
P. Rotwein ◽  
J. L. Sadow ◽  
J. Novakofski ◽  
P. J. Bechtel

We have investigated the hypothesis that there is local regulation of insulin-like growth factor (IGF) gene expression during skeletal muscle growth. Compensatory hypertrophy was induced in the soleus, a predominantly slow-twitch muscle, and plantaris, a fast-twitch muscle, in 11- to 12-wk-old female Wistar rats by unilateral cutting of the distal gastrocnemius tendon. Animals were killed 2, 4, or 8 days later, and muscles of the nonoperated leg served as controls. Muscle weight increased throughout the experimental period, reaching 127% (soleus) or 122% (plantaris) of control values by day 8. In both growing muscles, IGF-I mRNA, quantitated by a solution-hybridization nuclease-protection assay, rose by nearly threefold on day 2 and remained elevated throughout the experimental period. IGF-II mRNA levels also increased over controls. A more dramatic response was seen in hypophysectomized rats, where IGF-I mRNA levels rose by 8- to 13-fold, IGF-II values by 3- to 7-fold, and muscle mass increased on day 8 to 149% (soleus) or 133% (plantaris) of the control contralateral limb. These results indicate that signals propagated during muscle hypertrophy enhance the expression of both IGF genes, that modulation of IGF-I mRNA levels can occur in the absence of growth hormone, and that locally produced IGF-I and IGF-II may play a role in skeletal muscle growth.


1994 ◽  
Vol 150 (2) ◽  
pp. 235-237
Author(s):  
J. PINEDA ◽  
R. COYA ◽  
G. JACOBSSON ◽  
M. LAKE ◽  
K. HALL ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ruoyi Zheng ◽  
Wenming Chen ◽  
Weiting Xia ◽  
Jingyu Zheng ◽  
Qing Zhou

Purpose. To assess the expression of insulin-like growth factor binding protein (IGFBP) family and its prognostic impact in ovarian cancer (OC) patients. Materials and Methods. The mRNA expression and protein expression of individual IGFBPs in healthy ovarian samples and OC tissues were explored through Oncomine, Gene Expression Profiling Interactive Analysis, and Human Protein Atlas database. Additionally, the prognostic values of the six IGFBP members in patients with OC were evaluated by Kaplan-Meier plotter. Results. IGFBP2 and IGFBP4 mRNA expression were remarkably upregulated in patients with OC. To be specific, the mRNA expression of IGFBP2 was upregulated in patients with serous ovarian cancer (SOC), while IGFBP1/3/4/5/6 mRNA levels were downregulated. In addition, the IGFBP4 protein expression was upregulated in SOC, and the IGFBP6 protein expression was upregulated in both of SOC and endometrioid ovarian cancer (EOC) tissues. High IGFBP1 mRNA levels showed favorable overall survival (OS) and progression-free survival (PFS) in all OC. Meanwhile, increased IGFBP5/6 mRNA levels revealed worsen OS and PFS in all OC patients. IGFBP4/6 mRNA levels predicted unfavorable OS and PFS only in SOC patients. Moreover, the aberrant mRNA expression of IGFBP1/2/4/5/6 was correlated with significantly prognosis in patients receiving different chemotherapeutic regimens. Conclusion. This study indicates that the IGFBP family reveals distinct prognosis in patients with OC. IGFBP1/2/4/5/6 are useful prognostic predictors for chemotherapeutic effect in OC patients, and IGFBP2/4 are potential tumor markers for the diagnosis of OC.


1996 ◽  
Vol 319 (2) ◽  
pp. 455-461 ◽  
Author(s):  
Simon S WING ◽  
Nathalie BEDARD

Upon fasting, the ubiquitin-dependent proteolytic system is activated in skeletal muscle in parallel with the increases in rates of proteolysis. Levels of mRNA encoding the 14 kDa ubiquitin-conjugating enzyme (E214k), which can catalyse the first irreversible reaction in this pathway, rise and fall in parallel with the rates of proteolysis [Wing and Banville (1994) Am. J. Physiol. 267, E39-E48], indicating that the conjugation of ubiquitin to proteins is a regulated step. To characterize the mechanisms of this regulation, we have examined the effects of insulin, insulin-like growth factor I (IGF-I) and des(1–3) insulin-like growth factor I (DES-IGF-I), which does not bind IGF-binding proteins, on E214k mRNA levels in L6 myotubes. Insulin suppressed levels of E214k mRNA with an IC50 of 4×10-9 M, but had no effects on mRNAs encoding polyubiquitin and proteasome subunits C2 and C8, which, like E214k, also increase in skeletal muscle upon fasting. Reduction of E214k mRNA levels was more sensitive to IGF-I with an IC50 of approx. 5×10-10 M. During the incubation of these cells for 12 h there was significant secretion of IGF-I-binding proteins into the medium. DES-IGF-I, which has markedly reduced affinity for these binding proteins, was found to potently reduce E214k mRNA levels with an IC50 of 3×10-11 M. DES-IGF-I did not alter rates of transcription of the E214k gene, but enhanced the rate of degradation of the 1.2 kb mRNA transcript. The half-life of the 1.2 kb transcript was approximately one-third that of the 1.8 kb transcript and can explain the more marked regulation of this transcript observed previously. This indicates that the additional 3´ non-coding sequence in the 1.8 kb transcript confers stability. These observations suggest that IGF-I is an important regulator of E214k expression and demonstrate, for the first time, stimulation of degradation of a specific mRNA transcript by this hormone, while overall RNA accumulates.


Author(s):  
Annu Makker ◽  
Madhu Mati Goel ◽  
Dipti Nigam ◽  
Amita Pandey

Background: The “window of implantation” (WOI) is a transient but well defined period during which the hostile endometrial lining is transformed to a surface receptive to accept the embryo. Recently, data are beginning to accumulate suggesting negative influence of non-cavity distorting intramural uterine fibroids (NCD-IMF) on endometrial receptivity that may have implications for implantation failure. However, molecular mechanisms underlying infertility associated with NCD-IMF remain unclear. The aim of present study was to examine the expression and cellular distribution of insulin-like growth factor 1 receptor (IGF1R) during WOI in infertile women with NCD-IMF and fertile controls. While, reports are available that support role of IGF1R in mediating adhesive interaction with the implanting blastocyst, the effect of NCD-IMF on IGF1R expression during the WOI is not defined.Methods: Quantitative real-time polymerase chain reaction and immunohistochemistry were used to evaluate messenger RNA (mRNA) and protein expression of IGF1R in midsecretory endometrial biopsies obtained from infertile women with NCD-IMF (n=20) and healthy fertile controls (n=10).Results: As compared to fertile controls, significantly higher IGF1R: i) mRNA levels (1.59 fold up regulation; p=0.044) and ii) immunoscore in the luminal epithelium (8.94±3.13 versus 6.31±1.49; p=0.009) were observed in infertile women with NCD-IMF.Conclusions: Over expression of IGF1R in infertile women with NCD-IMF, during the window of receptivity, may result in altered ability of uterine epithelial cells for blastocyst adhesion and subsequent implantation, which might lead to poor reproductive outcome in these women.


1999 ◽  
Vol 163 (2) ◽  
pp. 281-288 ◽  
Author(s):  
P Andersson ◽  
T Gustafsson ◽  
HJ Arnqvist

We have investigated the expression and secretion of insulin-like growth factor binding proteins (IGFBPs-1 to -6) in human vascular smooth muscle cells (hVSMCs) cultured from human renal arteries. Solution hybridization was used to determine IGFBP mRNA levels and Western immunoblot to detect the corresponding peptides. The hVSMCs expressed mRNAs for IGFBPs-2 to -6; IGFBP-1 mRNA was not detected. IGFBPs-3, -4 and -6 mRNAs were the most abundant, IGFBP-5 was also highly expressed, whereas the IGFBP-2 mRNA was just above the limit of detection. Serum starvation for 48 h significantly decreased the mRNA levels of IGFBPs-2 to -5 and tended to decrease IGFBP-6 mRNA also. IGFBPs-2, -4, -5 and -6 peptides could be detected in conditioned medium, but IGFBP-3 peptide was not detected. IGFBP-4 was the only peptide detected without any concentration step. Low-molecular-mass immunoreactive degradation products were found for IGFBPs-2 and -4. Exogenous IGFBPs-1, -3 and -4 in concentrations of 50 ng/ml inhibited DNA synthesis induced by 1 nM IGF-I, whereas IGFBPs-2, -5 and -6 had no significant inhibitory effects at this concentration. We conclude from these results that all IGFBPs except IGFBP-1 are expressed in hVSMC. Our results indicate that locally produced, in addition to circulating, IGFBPs may have an important role in the regulation of hVSMC.


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