Evaluation of Allelic Expression of Imprinted Genes in Adult Human Blood

PubMed Central

Frost, Jennifer M.; Monk, Dave; Stojilkovic-Mikic, Taita; Woodfine, Kathryn; Chitty, Lyn S.; Murrell, Adele; Stanier, Philip; Moore, Gudrun E.

2010-01-01

Background Imprinted genes are expressed from only one allele in a parent-of-origin dependent manner. Loss of imprinted (LOI) expression can result in a variety of human disorders and is frequently reported in cancer. Biallelic expression of imprinted genes in adult blood has been suggested as a useful biomarker and is currently being investigated in colorectal cancer. In general, the expression profiles of imprinted genes are well characterised during human and mouse fetal development, but not in human adults. Methodology/Principal Findings We investigated quantitative expression of 36 imprinted genes in adult human peripheral blood leukocytes obtained from healthy individuals. Allelic expression was also investigated in B and T lymphocytes and myeloid cells. We found that 21 genes were essentially undetectable in adult blood. Only six genes were demonstrably monoallelic, and most importantly, we found that nine genes were either biallelic or showed variable expression in different individuals. Separated leukocyte populations showed the same expression patterns as whole blood. Differential methylation at each of the imprinting control loci analysed was maintained, including regions that contained biallelically expressed genes. This suggests in some cases methylation has become uncoupled from its role in regulating gene expression. Conclusions/Significance We conclude that only a limited set of imprinted genes, including IGF2 and SNRPN, may be useful for LOI cancer biomarker studies. In addition, blood is not a good tissue to use for the discovery of new imprinted genes. Finally, lymphocyte DNA methylation status in the adult may not always be a reliable indicator of monoallelic gene expression. PMID:21042416

Loss of insulin-like growth factor II imprinting is a hallmark associated with enhanced chemo/radiotherapy resistance in cancer stem cells.

PubMed

Zhao, Xin; Liu, Xiaoliang; Wang, Guanjun; Wen, Xue; Zhang, Xiaoying; Hoffman, Andrew R; Li, Wei; Hu, Ji-Fan; Cui, Jiuwei

2016-08-09

Insulin-like growth factor II (IGF2) is maternally imprinted in most tissues, but the epigenetic regulation of the gene in cancer stem cells (CSCs) has not been defined. To study the epigenetic mechanisms underlying self-renewal, we isolated CSCs and non-CSCs from colon cancer (HT29, HRT18, HCT116), hepatoma (Hep3B), breast cancer (MCF7) and prostate cancer (ASPC) cell lines. In HT29 and HRT18 cells that show loss of IGF2 imprinting (LOI), IGF2 was biallelically expressed in the isolated CSCs. Surprisingly, we also found loss of IGF2 imprinting in CSCs derived from cell lines HCT116 and ASPC that overall demonstrate maintenance of IGF2 imprinting. Using chromatin conformation capture (3C), we found that intrachromosomal looping between the IGF2 promoters and the imprinting control region (ICR) was abrogated in CSCs, in parallel with loss of IGF2 imprinting in these CSCs. Loss of imprinting led to increased IGF2 expression in CSCs, which have a higher rate of colony formation and greater resistance to chemotherapy and radiotherapy in vitro. These studies demonstrate that IGF2 LOI is a common feature in CSCs, even when the stem cells are derived from a cell line in which the general population of cells maintain IGF2 imprinting. This finding suggests that aberrant IGF2 imprinting may be an intrinsic epigenetic control mechanism that enhances stemness, self-renewal and chemo/radiotherapy resistance in cancer stem cells.

Reproductive performance and expression of imprinted genes in somatic cell cloned boars.

PubMed

Kawarasaki, Tatsuo; Enya, Satoko; Otake, Masayoshi; Shibata, Masatoshi; Mikawa, Satoshi

2017-11-01

To assess the performance of boars derived by somatic cell cloning, we analyzed various aspects of their reproductive characteristics and the expression of two imprinted genes. Cloned boars (cloned Duroc × Jinhua) were analyzed for birth weight, growth rate, age at first ejaculation, semen characteristics and fertility, in comparison with naturally bred control boars of the same strain. The expression of imprinted genes was analyzed using the microsatellite marker SWC9 for the paternally expressed gene insulin-like growth factor -2 (IGF2) and with single nucleotide polymorphisms (SNPs) for the gene maternally expressed 3 (MEG3). The cloned boars had high production of semen and were nearly equal in level of fertility to conventional pigs; they showed similar characteristics as naturally bred boars of the same strains. The expression of IGF2 was partially disturbed, but this disturbed expression was not linked to a change in developmental fate or reproductive performance. These results indicate that use of cloned boars could be highly effective for proliferation of pigs with desirable characteristics, preservation of genetic resources and risk reduction against epidemic diseases, such as foot-and-mouth disease, through storage of somatic cells as a precautionary measure for use in regenerating pig populations after a future pandemic. © 2017 Japanese Society of Animal Science.

Expression of IGF-I, IGF-I receptor and IGF binding proteins-1, -2, -3, -4 and -5 in human atherectomy specimens.

PubMed

Grant, M B; Wargovich, T J; Ellis, E A; Tarnuzzer, R; Caballero, S; Estes, K; Rossing, M; Spoerri, P E; Pepine, C

1996-12-17

The molecular and cellular processes that induce rapid atherosclerotic plaque progression in patients with unstable angina and initiate restenosis following coronary interventional procedures are uncertain. We examined primary (de novo) and restenotic lesions retrieved at the time of directional coronary atherectomy for expression of insulin-like-growth factor-I (IGF-I). IGF-I receptor, and five IGF binding proteins (IGFBPs), IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 in smooth muscle cells (SMCs) using colloidal gold immunocytochemistry. IGF-1, its receptor and binding proteins were not detected in SMCs of normal coronary arteries. IGF-I localized primarily in synthetic smooth muscle cells (sSMCs) in both de novo and restenotic plaques. IGF-I receptor localized on sSMCs and their processes and colocalized with IGF-I. Although morphometric analysis of IGF-I and IGF-I receptor immunoreactivity in sSMCs of de novo and restenotic lesions showed comparable levels of IGF-I (3.2 +/- 1.0 and 2.9 +/- 0.9, respectively). IGF-I receptor was significantly higher in de novo lesions as compared to restenotic lesions (10.7 +/- 2.5 and 4.2 +/- 1.3, P < 0.05, respectively). IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4 and IGFBP-5 localized in the cytoplasm of sSMCs and in the extracellular matrix. Quantitative reverse transcription polymerase chain reaction (QRT-PCR) performed on de novo atherectomy specimens identified mRNA for IGF-I, IGF-I receptor, IGFBP-1, IGFBP-2, IGFBP-4, IGFBP-5 levels and detected mRNA for IGFBP-3. The expression of IGF-I, IGF-I receptor, and IGFBPs in atherectomy plaques suggests that the development of coronary obstructive lesions may be a result of changes in the IGF system.

DNA methylation modulates H19 and IGF2 expression in porcine female eye

PubMed Central

Wang, Dongxu; Wang, Guodong; Yang, Hao; Liu, Haibo; Li, Cuie; Li, Xiaolan; Lin, Chao; Song, Yuning; Li, Zhanjun; Liu, Dianfeng

2017-01-01

Abstract The sexually dimorphic expression of H19/IGF2 is evolutionarily conserved. To investigate whether the expression of H19/IGF2 in the female porcine eye is sex-dependent, gene expression and methylation status were evaluated using quantitative real-time PCR (qPCR) and bisulfite sequencing PCR (BSP). We hypothesized that H19/IGF2 might exhibit a different DNA methylation status in the female eye. In order to evaluate our hypothesis, parthenogenetic (PA) cells were used for analysis by qPCR and BSP. Our results showed that H19 and IGF2 were over-expressed in the female eye compared with the male eye (3-fold and 2-fold, respectively). We observed a normal monoallelic methylation pattern for H19 differentially methylated regions (DMRs). Compared with H19 DMRs, IGF2 DMRs showed a different methylation pattern in the eye. Taken together, these results suggest that elevated expression of H19/IGF2 is caused by a specific chromatin structure that is regulated by the DNA methylation status of IGF2 DMRs in the female eye. PMID:28266684

Subtle Decreases in DNA Methylation and Gene Expression at the Mouse Igf2 Locus Following Prenatal Alcohol Exposure: Effects of a Methyl-Supplemented Diet

PubMed Central

Downing, Chris; Johnson, Thomas E; Larson, Colin; Leakey, Tatiana I; Siegfried, Rachel N; Rafferty, Tonya M; Cooney, Craig A

2010-01-01

C57BL/6J (B6) mice are susceptible to in utero growth retardation and a number of morphological malformations following prenatal alcohol exposure, while DBA/2J (D2) mice are relatively resistant. We have previously shown that genomic imprinting may play a role in differential sensitivity between B6 and D2 (Downing and Gilliam 1999). The best characterized mechanism mediating genomic imprinting is differential DNA methylation. In the present study we examined DNA methylation and gene expression, in both embryonic and placental tissue, at the mouse Igf2 locus following in utero ethanol exposure. We also examined the effects of a methyl-supplemented diet on methylation and ethanol teratogenesis. In embryos from susceptible B6 mice, we found small decreases in DNA methylation at four CpG sites in one of the differentially methylated regions of the Igf2 locus; only one of the four sites showed a statistically significant decrease. We observed no significant decreases in methylation in placentae. All Igf2 transcripts showed approximately 1.5 fold decreases following intrauterine alcohol exposure. Placing dams on a methyl-supplemented diet before pregnancy and throughout gestation brought methylation back up to control levels. Methyl-supplementation also resulted in lower prenatal mortality, greater prenatal growth, and decreased digit malformations; it dramatically reduced vertebral malformations. Thus, while prenatal alcohol had only small effects on DNA methylation at the Igf2 locus, placing dams on a methyl-supplemented diet partially ameliorated ethanol teratogenesis. PMID:20705422

Effects of a novel SNP of IGF2R gene on growth traits and expression rate of IGF2R and IGF2 genes in gluteus medius muscle of Egyptian buffalo.

PubMed

El-Magd, Mohammed Abu; Abo-Al-Ela, Haitham G; El-Nahas, Abeer; Saleh, Ayman A; Mansour, Ali A

2014-05-01

Insulin-like growth factor 2 receptor (IGF2R) is responsible for degradation of the muscle development initiator, IGF2, and thus it can be used as a marker for selection strategies in the farm animals. The aim of this study was to search for polymorphisms in three coding loci of IGF2R, and to analyze their effect on the growth traits and on the expression levels of IGF2R and IGF2 genes in the gluteus medius muscle of Egyptian buffaloes. A novel A266C SNP was detected in the coding sequences of the third IGF2R locus (at nucleotide number 51 of exon 23) among Egyptian water buffaloes. This SNP was non-synonymous mutation and led to replacement of Y (tyrosine) amino acid (aa) by D (aspartic acid) aa. Three different single-strand conformation polymorphism patterns were observed in the third IGF2R locus: AA, AC, and CC with frequencies of 0.555, 0.195, and 0.250, respectively. Statistical analysis showed that the homozygous AA genotype significantly associated with the average daily gain than AC and CC genotypes from birth to 9 mo of age. Expression analysis showed that the A266C SNP was correlated with IGF2, but not with IGF2R, mRNA levels in the gluteus medius muscle of Egyptian buffaloes. The highest IGF2 mRNA level was estimated in the muscle of animals with the AA homozygous genotype as compared to the AC heterozygotes and CC homozygotes. We conclude that A266C SNP at nucleotide number 51 of exon 23 of the IGF2R gene is associated with the ADG during the early stages of life (from birth to 9 mo of age) and this effect is accompanied by, and may be caused by, increased expression levels of the IGF2 gene. Copyright © 2014 Elsevier B.V. All rights reserved.

The landscape of genomic imprinting across diverse adult human tissues

PubMed Central

Baran, Yael; Subramaniam, Meena; Biton, Anne; Tukiainen, Taru; Tsang, Emily K.; Rivas, Manuel A.; Pirinen, Matti; Gutierrez-Arcelus, Maria; Smith, Kevin S.; Kukurba, Kim R.; Zhang, Rui; Eng, Celeste; Torgerson, Dara G.; Urbanek, Cydney; Li, Jin Billy; Rodriguez-Santana, Jose R.; Burchard, Esteban G.; Seibold, Max A.; MacArthur, Daniel G.; Montgomery, Stephen B.; Zaitlen, Noah A.; Lappalainen, Tuuli

2015-01-01

Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues. PMID:25953952

Deregulation of an imprinted gene network in prostate cancer

PubMed Central

Ribarska, Teodora; Goering, Wolfgang; Droop, Johanna; Bastian, Klaus-Marius; Ingenwerth, Marc; Schulz, Wolfgang A

2014-01-01

Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes. PMID:24513574

Deregulation of an imprinted gene network in prostate cancer.

PubMed

Ribarska, Teodora; Goering, Wolfgang; Droop, Johanna; Bastian, Klaus-Marius; Ingenwerth, Marc; Schulz, Wolfgang A

2014-05-01

Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes.

Effects of endocrine disruptors on imprinted gene expression in the mouse embryo

PubMed Central

Tran, Diana A; Rivas, Guillermo E; Singh, Purnima; Pfeifer, Gerd P

2011-01-01

Environmental endocrine disruptors (EDs) are synthetic chemicals that resemble natural hormones and are known to cause epigenetic perturbations. EDs have profound effects on development and fertility. Imprinted genes had been identified as candidate susceptibility loci to environmental insults because they are functionally haploid, and because the imprints undergo epigenetic resetting between generations. To screen for possible epigenetic perturbations caused by EDs at imprinted loci, we treated pregnant mice daily between 8.5 and 12.5 days post coitum (dpc) with di-(2-ethylhexyl)-phthalate (DEHP), bisphenol A (BPA), vinclozolin (VZ) or control oil vehicle. After isolating RNA from the placenta, yolk sac, amnion, head, body, heart, liver, lung, stomach and intestines of 13.5 dpc embryos we measured the allele-specific expression of 39 imprinted transcripts using multiplex single nucleotide primer extension (SNuPE) assays. In this representative data set we identified only a small number of transcripts that exhibited a substantial relaxation of imprinted expression with statistical significance: Slc22a18 with 10% relaxation in the embryo after BPA treatment; Rtl1as with 11 and 16% relaxation in the lung and placenta, respectively after BPA treatment; and Rtl1 with 12% relaxation in the yolk sac after DEHP treatment. Additionally, the standard deviation of allele-specificity increased in various organs after ED treatment for several transcripts including Igf2r, Rasgrf1, Usp29, Slc38a4 and Xist. Our data suggest that the maintenance of strongly biased monoallelic expression of imprinted genes is generally insensitive to EDs in the 13.5 dpc embryo and extra-embryonic organs, but is not immune to those effects. PMID:21636974

The landscape of genomic imprinting across diverse adult human tissues.

PubMed

Baran, Yael; Subramaniam, Meena; Biton, Anne; Tukiainen, Taru; Tsang, Emily K; Rivas, Manuel A; Pirinen, Matti; Gutierrez-Arcelus, Maria; Smith, Kevin S; Kukurba, Kim R; Zhang, Rui; Eng, Celeste; Torgerson, Dara G; Urbanek, Cydney; Li, Jin Billy; Rodriguez-Santana, Jose R; Burchard, Esteban G; Seibold, Max A; MacArthur, Daniel G; Montgomery, Stephen B; Zaitlen, Noah A; Lappalainen, Tuuli

2015-07-01

Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues. © 2015 Baran et al.; Published by Cold Spring Harbor Laboratory Press.

Generation of Five Human Lactoferrin Transgenic Cloned Goats Using Fibroblast Cells and Their Methylation Status of Putative Differential Methylation Regions of IGF2R and H19 Imprinted Genes

PubMed Central

Sun, Yanyan; Zhang, Yanli; Wang, Ziyu; Song, Yang; Wang, Feng

2013-01-01

Background Somatic cell nuclear transfer (SCNT) is a promising technique to produce transgenic cloned mammalian, including transgenic goats which may produce Human Lactoferrin (hLF). However, success percentage of SCNT is low, because of gestational and neonatal failure of transgenic embryos. According to the studies on cattle and mice, DNA methylation of some imprinted genes, which plays a vital role in the reprogramming of embryo in NT maybe an underlying mechanism. Methodology/Principal Findings Fibroblast cells were derived from the ear of a two-month-old goat. The vector expressing hLF was constructed and transfected into fibroblasts. G418 selection, EGFP expression, PCR, and cell cycle distribution were applied sequentially to select transgenic cells clones. After NT and embryo transfer, five transgenic cloned goats were obtained from 240 cloned transgenic embryos. These transgenic goats were identified by 8 microsatellites genotyping and southern blot. Of the five transgenic goats, 3 were lived after birth, while 2 were dead during gestation. We compared differential methylation regions (DMR) pattern of two paternally imprinted genes (H19 and IGF2R) of the ear tissues from the lived transgenic goats, dead transgenic goats, and control goats from natural reproduction. Hyper-methylation pattern appeared in cloned aborted goats, while methylation status was relatively normal in cloned lived goats compared with normal goats. Conclusions/Significance In this study, we generated five hLF transgenic cloned goats by SCNT. This is the first time the DNA methylation of lived and dead transgenic cloned goats was compared. The results demonstrated that the methylation status of DMRs of H19 and IGF2R were different in lived and dead transgenic goats and therefore this may be potentially used to assess the reprogramming status of transgenic cloned goats. Understanding the pattern of gene imprinting may be useful to improve cloning techniques in future. PMID:24204972

Relaxation of Insulin-Like Growth Factor II Imprinting in Prostate Cancer Development

DTIC Science & Technology

2005-01-01

in the Results in Senescence and Biallelic IGF2 Expression- Hypo - mouse and are putative ICRs (Fig. 3A). At MR2, located within methylation has been...elderly. In In mammals, reproduction is controlled by the hypo - the case of prostate cancer, the most commonly diagnosed thalamic--pituitary-gonadal... caloric the ligands IGF-I, IGF-II, cell-surface receptors and binding intake or hormonal exposure), loss of imprinting of IGF-II proteins. Epidemiological

Complete Biallelic Insulation at the H19/Igf2 Imprinting Control Region Position Results in Fetal Growth Retardation and Perinatal Lethality

PubMed Central

Lee, Dong-Hoon; Singh, Purnima; Tsark, Walter M. K.; Szabó, Piroska E.

2010-01-01

Background The H19/Igf2 imprinting control region (ICR) functions as an insulator exclusively in the unmethylated maternal allele, where enhancer-blocking by CTCF protein prevents the interaction between the Igf2 promoter and the distant enhancers. DNA methylation inhibits CTCF binding in the paternal ICR allele. Two copies of the chicken β-globin insulator (ChβGI)2 are capable of substituting for the enhancer blocking function of the ICR. Insulation, however, now also occurs upon paternal inheritance, because unlike the H19 ICR, the (ChβGI)2 does not become methylated in fetal male germ cells. The (ChβGI)2 is a composite insulator, exhibiting enhancer blocking by CTCF and chromatin barrier functions by USF1 and VEZF1. We asked the question whether these barrier proteins protected the (ChβGI)2 sequences from methylation in the male germ line. Methodology/Principal Findings We genetically dissected the ChβGI in the mouse by deleting the binding sites USF1 and VEZF1. The methylation of the mutant versus normal (ChβGI)2 significantly increased from 11% to 32% in perinatal male germ cells, suggesting that the barrier proteins did have a role in protecting the (ChβGI)2 from methylation in the male germ line. Contrary to the H19 ICR, however, the mutant (mChβGI)2 lacked the potential to attain full de novo methylation in the germ line and to maintain methylation in the paternal allele in the soma, where it consequently functioned as a biallelic insulator. Unexpectedly, a stricter enhancer blocking was achieved by CTCF alone than by a combination of the CTCF, USF1 and VEZF1 sites, illustrated by undetectable Igf2 expression upon paternal transmission. Conclusions/Significance In this in vivo model, hypomethylation at the ICR position together with fetal growth retardation mimicked the human Silver-Russell syndrome. Importantly, late fetal/perinatal death occurred arguing that strict biallelic insulation at the H19/Igf2 ICR position is not tolerated in development

Gastric cancer: the role of insulin-like growth factor 2 (IGF 2) and its receptors (IGF 1R and M6-P/IGF 2R).

PubMed

Pavelić, Kresimir; Kolak, Toni; Kapitanović, Sanja; Radosević, Senka; Spaventi, Sime; Kruslin, Bozo; Pavelić, Jasminka

2003-11-01

Insulin-like growth factor 2 (IGF 2) appears to be involved in the progression of many tumours. It binds to at least two different types of receptor: IGF type 1 (IGF 1R) and mannose 6-phosphate/IGF type 2 (M6-P/IGF 2R). Ligand binding to IGF 1R provokes mitogenic and anti-apoptotic effects. M6-P/IGF 2R has a tumour suppressor function--it mediates IGF 2 degradation. Mutation of M6-P/IGF 2R causes both diminished growth suppression and augmented growth stimulation. The aim of this study was to investigate the role of IGF 2 and its receptors (IGF 1R and IGF 2R) in human gastric cancer. The expression of IGF 2 and its receptors was measured in order to analyse the possible correlation between the activity of these genes and cell proliferation in two different gastric tumour types: diffuse and intestinal. The effect of IGF 1 receptor blockage on cell proliferation and anchorage-independent cell growth was also examined. Increased expression of IGF 2 and IGF 1R genes (at the mRNA and protein level) was found in gastric cancer when compared with non-tumour tissue. Furthermore, there was a significant difference between IGF 2 expression in the more aggressive diffuse type and that in the intestinal type of gastric cancer. Moreover, the IGF 2 peptide level in the culture media obtained from the diffuse type of cancer cells was significantly higher when compared with the intestinal type. The level of IGF 2 peptide in the conditioned media strongly correlated with [3H]thymidine incorporation and cell proliferation. On the contrary, IGF 2R mRNA expression was much higher in the intestinal type of cancer than in the diffuse type. In addition, IGF 2R protein expression was substantially lower with progression of the diffuse cancer type to a higher stage. The alphaIR3 monoclonal antibody strongly inhibited [3H]thymidine incorporation and decreased the number of colonies in soft agar of cells overexpressing IGF 2. These findings suggest that members of the IGF family are involved

Butyrate induced IGF2 activation correlated with distinct chromatin landscapes due to histone modification

USDA-ARS?s Scientific Manuscript database

Histone modification has emerged as a very important mechanism regulating the transcriptional status of the genome. Insulin-like growth factor 2 (IGF2) is a peptide hormone controlling various cellular processes such as proliferation and apoptosis. IGF2 and H19 are reciprocally regulated imprinted ...

GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.

PubMed

Nornberg, Bruna Félix; Almeida, Daniela Volcan; Figueiredo, Márcio Azevedo; Marins, Luis Fernando

2016-10-01

The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.

Biochemical Characterization of Individual Human Glycosylated pro-Insulin-like Growth Factor (IGF)-II and big-IGF-II Isoforms Associated with Cancer

PubMed Central

Greenall, Sameer A.; Bentley, John D.; Pearce, Lesley A.; Scoble, Judith A.; Sparrow, Lindsay G.; Bartone, Nicola A.; Xiao, Xiaowen; Baxter, Robert C.; Cosgrove, Leah J.; Adams, Timothy E.

2013-01-01

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed “pro” and “big” IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling. PMID:23166326

Biochemical characterization of individual human glycosylated pro-insulin-like growth factor (IGF)-II and big-IGF-II isoforms associated with cancer.

PubMed

Greenall, Sameer A; Bentley, John D; Pearce, Lesley A; Scoble, Judith A; Sparrow, Lindsay G; Bartone, Nicola A; Xiao, Xiaowen; Baxter, Robert C; Cosgrove, Leah J; Adams, Timothy E

2013-01-04

Insulin-like growth factor II (IGF-II) is a major embryonic growth factor belonging to the insulin-like growth factor family, which includes insulin and IGF-I. Its expression in humans is tightly controlled by maternal imprinting, a genetic restraint that is lost in many cancers, resulting in up-regulation of both mature IGF-II mRNA and protein expression. Additionally, increased expression of several longer isoforms of IGF-II, termed "pro" and "big" IGF-II, has been observed. To date, it is ambiguous as to what role these IGF-II isoforms have in initiating and sustaining tumorigenesis and whether they are bioavailable. We have expressed each individual IGF-II isoform in their proper O-glycosylated format and established that all bind to the IGF-I receptor and both insulin receptors A and B, resulting in their activation and subsequent stimulation of fibroblast proliferation. We also confirmed that all isoforms are able to be sequestered into binary complexes with several IGF-binding proteins (IGFBP-2, IGFBP-3, and IGFBP-5). In contrast to this, ternary complex formation with IGFBP-3 or IGFBP-5 and the auxillary protein, acid labile subunit, was severely diminished. Furthermore, big-IGF-II isoforms bound much more weakly to purified ectodomain of the natural IGF-II scavenging receptor, IGF-IIR. IGF-II isoforms thus possess unique biological properties that may enable them to escape normal sequestration avenues and remain bioavailable in vivo to sustain oncogenic signaling.

Transcription Factor ZBED6 Mediates IGF2 Gene Expression by Regulating Promoter Activity and DNA Methylation in Myoblasts

NASA Astrophysics Data System (ADS)

Huang, Yong-Zhen; Zhang, Liang-Zhi; Lai, Xin-Sheng; Li, Ming-Xun; Sun, Yu-Jia; Li, Cong-Jun; Lan, Xian-Yong; Lei, Chu-Zhao; Zhang, Chun-Lei; Zhao, Xin; Chen, Hong

2014-04-01

Zinc finger, BED-type containing 6 (ZBED6) is an important transcription factor in placental mammals, affecting development, cell proliferation and growth. In this study, we found that the expression of the ZBED6 and IGF2 were upregulated during C2C12 differentiation. The IGF2 expression levels were negatively associated with the methylation status in beef cattle (P < 0.05). A luciferase assay for the IGF2 intron 3 and P3 promoter showed that the mutant-type 439 A-SNP-pGL3 in driving reporter gene transcription is significantly higher than that of the wild-type 439 G-SNP-pGL3 construct (P < 0.05). An over-expression assay revealed that ZBED6 regulate IGF2 expression and promote myoblast differentiation. Furthermore, knockdown of ZBED6 led to IGF2 expression change in vitro. Taken together, these results suggest that ZBED6 inhibits IGF2 activity and expression via a G to A transition disrupts the interaction. Thus, we propose that ZBED6 plays a critical role in myogenic differentiation.

Maternal nutrition during pregnancy is associated with differential expression of imprinted genes and DNA methyltranfereases in muscle of beef cattle offspring.

PubMed

Wang, X; Lan, X; Radunz, A E; Khatib, H

2015-01-01

Maternal diet during pregnancy is a major determinant of the fetal developmental competence and may induce long-lasting epigenetic changes to the offspring. Imprinted genes have important roles in fetal programming, growth, and development. There are, however, limited data available on the influence of maternal diet on the expression of imprinted genes in beef cattle. Therefore, the objective of this study was to analyze the impact of maternal diet during pregnancy on the expression of 5 imprinted genes and 3 DNA methyltransferase genes in longissimus dorsi muscle from Angus calves. A total of 36 Angus-cross cows were inseminated to a single sire and on Day 135 of gestation they were randomly assigned to either low-starch (haylage) or high-starch (corn silage) diets. Diets were initially formulated to provide isocaloric and isonitrogenous intake. The H19, MEG8, IGF2R, and DNMT3a genes showed differential expression in longissimus dorsi muscle in calves between the diet groups. Given that high-starch diet is a source of energy for muscle growth and feed conversion efficiency in postnatal development, the mechanisms by which this diet affected expression of imprinted genes should be further explored.

Addiction to the IGF2-ID1-IGF2 circuit for maintenance of the breast cancer stem-like cells

PubMed Central

Tominaga, K; Shimamura, T; Kimura, N; Murayama, T; Matsubara, D; Kanauchi, H; Niida, A; Shimizu, S; Nishioka, K; Tsuji, E-i; Yano, M; Sugano, S; Shimono, Y; Ishii, H; Saya, H; Mori, M; Akashi, K; Tada, K-i; Ogawa, T; Tojo, A; Miyano, S; Gotoh, N

2017-01-01

The transcription factor nuclear factor-κB (NF-κB) has important roles for tumorigenesis, but how it regulates cancer stem cells (CSCs) remains largely unclear. We identified insulin-like growth factor 2 (IGF2) is a key target of NF-κB activated by HER2/HER3 signaling to form tumor spheres in breast cancer cells. The IGF2 receptor, IGF1 R, was expressed at high levels in CSC-enriched populations in primary breast cancer cells. Moreover, IGF2-PI3K (IGF2-phosphatidyl inositol 3 kinase) signaling induced expression of a stemness transcription factor, inhibitor of DNA-binding 1 (ID1), and IGF2 itself. ID1 knockdown greatly reduced IGF2 expression, and tumor sphere formation. Finally, treatment with anti-IGF1/2 antibodies blocked tumorigenesis derived from the IGF1Rhigh CSC-enriched population in a patient-derived xenograft model. Thus, NF-κB may trigger IGF2-ID1-IGF2-positive feedback circuits that allow cancer stem-like cells to appear. Then, they may become addicted to the circuits. As the circuits are the Achilles' heels of CSCs, it will be critical to break them for eradication of CSCs. PMID:27546618

Bisphenol A Exposure Disrupts Genomic Imprinting in the Mouse

PubMed Central

Susiarjo, Martha; Sasson, Isaac; Mesaros, Clementina; Bartolomei, Marisa S.

2013-01-01

Exposure to endocrine disruptors is associated with developmental defects. One compound of concern, to which humans are widely exposed, is bisphenol A (BPA). In model organisms, BPA exposure is linked to metabolic disorders, infertility, cancer, and behavior anomalies. Recently, BPA exposure has been linked to DNA methylation changes, indicating that epigenetic mechanisms may be relevant. We investigated effects of exposure on genomic imprinting in the mouse as imprinted genes are regulated by differential DNA methylation and aberrant imprinting disrupts fetal, placental, and postnatal development. Through allele-specific and quantitative real-time PCR analysis, we demonstrated that maternal BPA exposure during late stages of oocyte development and early stages of embryonic development significantly disrupted imprinted gene expression in embryonic day (E) 9.5 and 12.5 embryos and placentas. The affected genes included Snrpn, Ube3a, Igf2, Kcnq1ot1, Cdkn1c, and Ascl2; mutations and aberrant regulation of these genes are associated with imprinting disorders in humans. Furthermore, the majority of affected genes were expressed abnormally in the placenta. DNA methylation studies showed that BPA exposure significantly altered the methylation levels of differentially methylated regions (DMRs) including the Snrpn imprinting control region (ICR) and Igf2 DMR1. Moreover, exposure significantly reduced genome-wide methylation levels in the placenta, but not the embryo. Histological and immunohistochemical examinations revealed that these epigenetic defects were associated with abnormal placental development. In contrast to this early exposure paradigm, exposure outside of the epigenetic reprogramming window did not cause significant imprinting perturbations. Our data suggest that early exposure to common environmental compounds has the potential to disrupt fetal and postnatal health through epigenetic changes in the embryo and abnormal development of the placenta. PMID

Increased expression of both insulin receptor substrates 1 and 2 confers increased sensitivity to IGF-1 stimulated cell migration.

PubMed

de Blaquière, Gail E; May, Felicity E B; Westley, Bruce R

2009-06-01

Insulin-like growth factors (IGFs) are thought to promote tumour progression and metastasis in part by stimulating cell migration. Insulin receptor substrate-1 (IRS-1) and IRS-2 are multisite docking proteins positioned immediately downstream from the type I IGF and insulin receptors. IRS-2 but not IRS-1 has been reported to be involved in the migratory response of breast cancer cells to IGFs. The purpose of this investigation was to determine if IRS-1 is involved in, and to assess the contributions of IRS-1 and IRS-2 to, the migratory response of breast cancer cells to IGFs. The expression of IRS-1 and IRS-2 varied considerably between ten breast cancer cell lines. Oestrogen increases expression of the type I IGF receptor, IRS-1 and IRS-2 in MCF-7 and ZR-75 cells. Oestrogens may control the sensitivity of breast cancer cells to IGFs by regulating the expression of components of the IGF signal transduction pathway. The migratory response to a range of IGF-1 concentrations was measured in MCF-7 and MDA-MB-231 breast cancer cells in which IRS-1 and IRS-2 levels were modulated using a doxycycline-inducible expression system. Induction of both IRS-1 and IRS-2 expression increased the sensitivity of the migratory response to IGF-1 but did not increase the magnitude of the response stimulated at higher concentrations of IGF-1. Knockdown of IRS-1, IRS-2 and the type I IGF receptor in MCF-7 and MDA-MB-2231 cells decreased sensitivity to IGF-1. We conclude that both IRS-1 and IRS-2 control the migratory response of breast cancer cells to IGF-1 and may, therefore, be key molecules in determining breast cancer spread.

Imprinted gene expression in fetal growth and development.

PubMed

Lambertini, L; Marsit, C J; Sharma, P; Maccani, M; Ma, Y; Hu, J; Chen, J

2012-06-01

Experimental studies showed that genomic imprinting is fundamental in fetoplacental development by timely regulating the expression of the imprinted genes to overlook a set of events determining placenta implantation, growth and embryogenesis. We examined the expression profile of 22 imprinted genes which have been linked to pregnancy abnormalities that may ultimately influence childhood development. The study was conducted in a subset of 106 placenta samples, overrepresented with small and large for gestational age cases, from the Rhode Island Child Health Study. We investigated associations between imprinted gene expression and three fetal development parameters: newborn head circumference, birth weight, and size for gestational age. Results from our investigation show that the maternally imprinted/paternally expressed gene ZNF331 inversely associates with each parameter to drive smaller fetal size, while paternally imprinted/maternally expressed gene SLC22A18 directly associates with the newborn head circumference promoting growth. Multidimensional Scaling analysis revealed two clusters within the 22 imprinted genes which are independently associated with fetoplacental development. Our data suggest that cluster 1 genes work by assuring cell growth and tissue development, while cluster 2 genes act by coordinating these processes. Results from this epidemiologic study offer solid support for the key role of imprinting in fetoplacental development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Expression and imprinting of MAGEL2 suggest a role in Prader-willi syndrome and the homologous murine imprinting phenotype.

PubMed

Lee, S; Kozlov, S; Hernandez, L; Chamberlain, S J; Brannan, C I; Stewart, C L; Wevrick, R

2000-07-22

Prader-Willi syndrome (PWS) is caused by the loss of expression of imprinted genes in chromosome 15q11-q13. Affected individuals exhibit neonatal hypotonia, developmental delay and childhood-onset obesity. Necdin, a protein implicated in the terminal differentiation of neurons, is the only PWS candidate gene to reduce viability when disrupted in a mouse model. In this study, we have characterized MAGEL2 (also known as NDNL1), a gene with 51% amino acid sequence similarity to necdin and located 41 kb distal to NDN in the PWS deletion region. MAGEL2 is expressed predominantly in brain, the primary tissue affected in PWS and in several fetal tissues as shown by northern blot analysis. MAGEL2 is imprinted with monoallelic expression in control brain, and paternal-only expression in the central nervous system as demonstrated by its lack of expression in brain from a PWS-affected individual. The orthologous mouse gene (Magel2) is located within 150 kb of NDN:, is imprinted with paternal-only expression and is expressed predominantly in late developmental stages and adult brain as shown by northern blotting, RT-PCR and whole-mount RNA in situ hybridization. Magel2 distribution partially overlaps that of NDN:, with strong expression being detected in the central nervous system in mid-gestation mouse embryos by in situ hybridization. We hypothesize that, although loss of necdin expression may be important in the neonatal presentation of PWS, loss of MAGEL2 may be critical to abnormalities in brain development and dysmorphic features in individuals with PWS.

The dipeptide Pro-Asp promotes IGF-1 secretion and expression in hepatocytes by enhancing JAK2/STAT5 signaling pathway.

PubMed

Wang, Songbo; Wang, Guoqing; Zhang, Mengyuan; Zhuang, Lu; Wan, Xiaojuan; Xu, Jingren; Wang, Lina; Zhu, Xiaotong; Gao, Ping; Xi, Qianyun; Zhang, Yongliang; Shu, Gang; Jiang, Qingyan

2016-11-15

It has been implicated that IGF-1 secretion can be regulated by dietary protein. However, whether the dipeptides, one of digested products of dietary protein, have influence on IGF-1 secretion remain largely unknown. Our study aimed to investigate the effects of the dipeptide Pro-Asp on IGF-1 secretion and expression in hepatocytes and to explore the possible underlying mechanisms. Our findings demonstrated that Pro-Asp promoted the secretion and gene expression of IGF-1 in HepG2 cells and primary porcine hepatocytes. Meanwhile, Pro-Asp activated the ERK and Akt signaling pathways, downstream of IGF-1. In addition, Pro-Asp enhanced GH-mediated JAK2/STAT5 signaling pathway, while inhibition of JAK2/STAT5 blocked the promotive effect of Pro-Asp on IGF-1 secretion and expression. Moreover, acute injection of Pro-Asp stimulated IGF-1 expression and activated JAK2/STAT5 signaling pathway in mice liver. Together, these results suggested that the dipeptide Pro-Asp promoted IGF-1 secretion and expression in hepatocytes by enhancing GH-mediated JAK2/STAT5 signaling pathway. Copyright © 2016. Published by Elsevier Ireland Ltd.

Transcriptional regulation of IGF-I expression in skeletal muscle

NASA Technical Reports Server (NTRS)

McCall, G. E.; Allen, D. L.; Haddad, F.; Baldwin, K. M.

2003-01-01

The present study investigated the role of transcription in the regulation of insulin-like growth factor (IGF)-I expression in skeletal muscle. RT-PCR was used to determine endogenous expression of IGF-I pre-mRNA and mRNA in control (Con) and functionally overloaded (FO) rat plantaris. The transcriptional activities of five different-length IGF-I promoter fragments controlling transcription of a firefly luciferase (FLuc) reporter gene were tested in vitro by transfection of myoblasts or in vivo during FO by direct gene transfer into the plantaris. Increased endogenous IGF-I gene transcription during 7 days of plantaris FO was evidenced by an approximately 140-160% increase (P < 0.0001) in IGF-I pre-mRNA (a transcriptional marker). IGF-I mRNA expression also increased by approximately 90% (P < 0.0001), and it was correlated (R = 0.93; P < 0.0001) with the pre-mRNA increases. The three longest IGF-I exon 1 promoters induced reporter gene expression in proliferating C2C12 and L6E9 myoblasts. In differentiated L6E9 myotubes, promoter activity increased approximately two- to threefold over myoblasts. Overexpression of calcineurin and MyoD increased the activity of the -852/+192 promoter in C2C12 myotubes by approximately 5- and approximately 18-fold, respectively. However, FO did not induce these exogenous promoter fragments. Nevertheless, the present findings are consistent with the hypothesis that the IGF-I gene is transcriptionally regulated during muscle hypertrophy in vivo as evidenced by the induction of the endogenous IGF-I pre-mRNA during plantaris FO. The exon 1 promoter region of the IGF-I gene is sufficient to direct inducible expression in vitro; however, an in vivo response to FO may require elements outside the -852/+346 region of the exon 1 IGF-I promoter or features inherent to the endogenous IGF-I gene.

Let-7b Regulates Myoblast Proliferation by Inhibiting IGF2BP3 Expression in Dwarf and Normal Chicken

PubMed Central

Lin, Shumao; Luo, Wen; Ye, Yaqiong; Bekele, Endashaw J.; Nie, Qinghua; Li, Yugu; Zhang, Xiquan

2017-01-01

The sex-linked dwarf chicken is caused by the mutation of growth hormone receptor (GHR) gene and characterized by shorter shanks, lower body weight, smaller muscle fiber diameter and fewer muscle fiber number. However, the precise regulatory pathways that lead to the inhibition of skeletal muscle growth in dwarf chickens still remain unclear. Here we found a let-7b mediated pathway might play important role in the regulation of dwarf chicken skeletal muscle growth. Let-7b has higher expression in the skeletal muscle of dwarf chicken than in normal chicken, and the expression of insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which is a translational activator of IGF2, showed opposite expression trend to let-7b. In vitro cellular assays validated that let-7b directly inhibits IGF2BP3 expression through binding to its 3′UTR region, and the protein level but not mRNA level of IGF2 would be reduced in let-7b overexpressed chicken myoblast. Let-7b can inhibit cell proliferation and induce cell cycle arrest in chicken myoblast through let-7b-IGF2BP3-IGF2 signaling pathway. Additionally, let-7b can also regulate skeletal muscle growth through let-7b-GHR-GHR downstream genes pathway, but this pathway is non-existent in dwarf chicken because of the deletion mutation of GHR 3′UTR. Notably, as the loss binding site of GHR for let-7b, let-7b has enhanced its binding and inhibition on IGF2BP3 in dwarf myoblast, suggesting that the miRNA can balance its inhibiting effect through dynamic regulate its binding to target genes. Collectively, these results not only indicate that let-7b can inhibit skeletal muscle growth through let-7b-IGF2BP3-IGF2 signaling pathway, but also show that let-7b regulates myoblast proliferation by inhibiting IGF2BP3 expression in dwarf and normal chickens. PMID:28736533

Expression at the imprinted dlk1-gtl2 locus is regulated by proneural genes in the developing telencephalon.

PubMed

Seibt, Julie; Armant, Olivier; Le Digarcher, Anne; Castro, Diogo; Ramesh, Vidya; Journot, Laurent; Guillemot, François; Vanderhaeghen, Pierre; Bouschet, Tristan

2012-01-01

Imprinting is an epigenetic mechanism that restrains the expression of about 100 genes to one allele depending on its parental origin. Several imprinted genes are implicated in neurodevelopmental brain disorders, such as autism, Angelman, and Prader-Willi syndromes. However, how expression of these imprinted genes is regulated during neural development is poorly understood. Here, using single and double KO animals for the transcription factors Neurogenin2 (Ngn2) and Achaete-scute homolog 1 (Ascl1), we found that the expression of a specific subset of imprinted genes is controlled by these proneural genes. Using in situ hybridization and quantitative PCR, we determined that five imprinted transcripts situated at the Dlk1-Gtl2 locus (Dlk1, Gtl2, Mirg, Rian, Rtl1) are upregulated in the dorsal telencephalon of Ngn2 KO mice. This suggests that Ngn2 influences the expression of the entire Dlk1-Gtl2 locus, independently of the parental origin of the transcripts. Interestingly 14 other imprinted genes situated at other imprinted loci were not affected by the loss of Ngn2. Finally, using Ngn2/Ascl1 double KO mice, we show that the upregulation of genes at the Dlk1-Gtl2 locus in Ngn2 KO animals requires a functional copy of Ascl1. Our data suggest a complex interplay between proneural genes in the developing forebrain that control the level of expression at the imprinted Dlk1-Gtl2 locus (but not of other imprinted genes). This raises the possibility that the transcripts of this selective locus participate in the biological effects of proneural genes in the developing telencephalon.

Expression at the Imprinted Dlk1-Gtl2 Locus Is Regulated by Proneural Genes in the Developing Telencephalon

PubMed Central

Seibt, Julie; Armant, Olivier; Le Digarcher, Anne; Castro, Diogo; Ramesh, Vidya; Journot, Laurent; Guillemot, François; Vanderhaeghen, Pierre; Bouschet, Tristan

2012-01-01

Imprinting is an epigenetic mechanism that restrains the expression of about 100 genes to one allele depending on its parental origin. Several imprinted genes are implicated in neurodevelopmental brain disorders, such as autism, Angelman, and Prader-Willi syndromes. However, how expression of these imprinted genes is regulated during neural development is poorly understood. Here, using single and double KO animals for the transcription factors Neurogenin2 (Ngn2) and Achaete-scute homolog 1 (Ascl1), we found that the expression of a specific subset of imprinted genes is controlled by these proneural genes. Using in situ hybridization and quantitative PCR, we determined that five imprinted transcripts situated at the Dlk1-Gtl2 locus (Dlk1, Gtl2, Mirg, Rian, Rtl1) are upregulated in the dorsal telencephalon of Ngn2 KO mice. This suggests that Ngn2 influences the expression of the entire Dlk1-Gtl2 locus, independently of the parental origin of the transcripts. Interestingly 14 other imprinted genes situated at other imprinted loci were not affected by the loss of Ngn2. Finally, using Ngn2/Ascl1 double KO mice, we show that the upregulation of genes at the Dlk1-Gtl2 locus in Ngn2 KO animals requires a functional copy of Ascl1. Our data suggest a complex interplay between proneural genes in the developing forebrain that control the level of expression at the imprinted Dlk1-Gtl2 locus (but not of other imprinted genes). This raises the possibility that the transcripts of this selective locus participate in the biological effects of proneural genes in the developing telencephalon. PMID:23139813

IGF-I stimulates ERβ and aromatase expression via IGF1R/PI3K/AKT-mediated transcriptional activation in endometriosis.

PubMed

Zhou, Yan; Zeng, Cheng; Li, Xin; Wu, Pei-Li; Yin, Ling; Yu, Xiao-Lan; Zhou, Ying-Fang; Xue, Qing

2016-08-01

Estrogen receptor beta (ERβ, encoded by ESR2 gene) and cytochrome P450 aromatase (encoded by CYP19A1 gene) play critical roles in endometriosis, and the levels of insulin-like growth factor-I (IGF-I) in the peritoneal fluid are significantly higher in patients with endometriosis compared with those in normal women. However, the effects and mechanisms of IGF-I on ERβ and aromatase expression remain to be fully elucidated. In this study, human endometriotic stromal cells (ESCs) and endometrial cells (EMs) derived from ovarian endometriomas and eutopic endometrial tissues. ESCs were cultured with IGF-I, signal pathway inhibitors, and siRNAs. ERβ and aromatase expression were measured by real-time PCR and Western, respectively. The binding of c-Jun and CREB to the ESR2 and CYP19A1 promoters was assessed by chromatin immunoprecipitation assay. Animal experiments were performed in a xenograft mouse model. Levels of IGF-I mRNA in ESCs were markedly higher than those in EMs. IGF-I upregulated ERβ and aromatase expression in ESCs after stimulation of the IGF1R/PI3K/AKT pathway. Following IGF-I treatment, a marked increase in c-Jun and CREB phosphorylation occurred, enhancing binding to the ESR2 and CYP19A1 promoters. An IGF1R inhibitor in vivo reduced IGF-I-induced endometriosis graft growth and ERβ and aromatase expression. In conclusion, this is the first report to describe a mechanistic analysis of ERβ and aromatase expression regulated by IGF-I in ESCs. Moreover, an IGF1R inhibitor impeded ectopic lesion growth in nude mice. These findings suggest that an inhibitor of IGF1R might have therapeutic potential as an antiendometriotic drug. Level of IGF-I mRNA in ESCs is markedly higher than that in EMs. IGF-I up-regulates ERβ and aromatase expression via IGF1R/PI3K/AKT pathway. C-Jun and CREB are recruited to ESR2 or CYP19A1 promoter by IGF-I stimulation. IGF-1R inhibitors in vivo impede the growth of ectopic lesions in nude mice.

Manganese induces IGF-1 and cyclooxygenase-2 gene expressions in the basal hypothalamus during prepubertal female development.

PubMed

Hiney, Jill K; Srivastava, Vinod K; Dees, William Les

2011-06-01

Precocious puberty is a significant child health problem, especially in girls, because 95% of cases are idiopathic. Our earlier studies demonstrated that low-dose levels of manganese (Mn) caused precocious puberty via stimulating the secretion of luteinizing hormone-releasing hormone (LHRH). Because glial-neuronal communications are important for the activation of LHRH secretion at puberty, we investigated the effects of prepubertal Mn exposure on specific glial-derived puberty-related genes known to affect neuronal LHRH release. Animals were supplemented with MnCl(2) (10 mg/kg) or saline by gastric gavage from day 12 until day 22 or day 29, then decapitated, and brains removed. The site of LHRH release is the medial basal hypothalamus (MBH), and tissues from this area were analyzed by real-time PCR for transforming growth factor α (TGFα), insulin-like growth factor-1 (IGF-1), and cyclooxygenase-2 (COX-2) messenger RNA levels. Protein levels for IGF-1 receptor (IGF-1R) were measured by Western blot analysis. LHRH gene expression was measured in the preoptic area/anteroventral periventricular (POA/AVPV) region. In the MBH, at 22 days, IGF-1 gene expression was increased (p < 0.05) with a concomitant increase (p < 0.05) in IGF-1R protein expression. Mn also increased (p < 0.01) COX-2 gene expression. At 29 days, the upregulation of IGF-1 (p < 0.05) and COX-2 (p < 0.05) continued in the MBH. At this time, we observed increased (p < 0.05) LHRH gene expression in the POA/AVPV. Additionally, Mn stimulated prostaglandin E(2) and LHRH release from 29-day-old median eminences incubated in vitro. These results demonstrate that Mn, through the upregulation of IGF-1 and COX-2, may promote maturational events and glial-neuronal communications facilitating the increased neurosecretory activity, including that of LHRH, resulting in precocious pubertal development.

Loss of insulin-like growth factor-II imprinting and the presence of screen-detected colorectal adenomas in women.

PubMed

Woodson, Karen; Flood, Andrew; Green, Lisa; Tangrea, Joseph A; Hanson, Jeffrey; Cash, Brooks; Schatzkin, Arthur; Schoenfeld, Phillip

2004-03-03

Loss of imprinting (LOI) of insulin-like growth factor-II (IGF-II) may be an inherited epigenetic trait that is polymorphic in the population, and its presence may predispose an individual to the development of colorectal cancer. We evaluated the association between LOI of IGF-II in normal colonic mucosal samples and adenomas in women participating in a colonoscopy screening study. Among 40 participants, 11 (27.5%) had LOI of IGF-II in their normal colonic mucosal tissue. After adjusting for body mass index and family history of colorectal cancer, LOI status was associated with a fivefold increased risk of adenoma formation (odds ratio = 5.2, 95% confidence interval = 1.0 to 26.7). On average, IGF-II expression was more than threefold higher among women with LOI of IGF-II than among women with normal imprinting status. Our findings support the hypothesis that LOI of IGF-II is an epigenetic trait polymorphic in the population and suggest that LOI of IGF-II may play a role in colorectal cancer. These findings are intriguing and need to be confirmed in larger studies.

Challenge with 17alpha-ethinylestradiol (EE2) during early development persistently impairs growth, differentiation, and local expression of IGF-I and IGF-II in immune organs of tilapia.

PubMed

Shved, Natallia; Berishvili, Giorgi; Häusermann, Eliane; D'Cotta, Helena; Baroiller, Jean-François; Eppler, Elisabeth

2009-03-01

The enormous expansion of world-wide aquaculture has led to increasing interest in the regulation of fish immune system. Estrogen has recently been shown to inhibit the endocrine (liver-derived) and autocrine/paracrine local insulin-like growth factor-I system in fish. In order to address the potential actions of estrogen on the IGF system in immune organs, tilapia were fed with 17alpha-ethinylestradiol (EE2)-enriched food from 10 to 40 days post fertilization (DPF) to induce functional feminization, an approach commonly used in aquaculture. EE2-treated and control fish were sampled at 75 and 165 DPF. The expression levels of ER-alpha, IGF-I, IGF-II and growth hormone receptor (GH-R) mRNA in spleen and head kidney were determined by real-time PCR and the expressing sites of IGF-I mRNA identified by in situ hybridisation. Ratios of spleen length and weight to body length and weight were determined. At 165 DPF, the length (4.9% vs. 7.6%) and weight (0.084% vs. 0.132%) ratios were significantly lowered in EE2-treated fish and number and size of the melanomacrophage centres were considerably reduced. At 75 DPF, both in spleen and head kidney of EE2-treated fish the expression levels of IGF-I and IGF-II mRNA were markedly diminished. The suppression was more pronounced for IGF-I (spleen: -12.071-fold; head kidney: -8.413-fold) than for IGF-II (spleen: -4.102-fold; head kidney: -1.342-fold). In agreement, clearly fewer leucocytes and macrophages in head kidney and spleen of EE2-treated fish contained IGF-I mRNA as shown by in situ hybridisation. ER-alpha mRNA expression in spleen was increased at 75 DPF but unchanged in head kidney. GH-R gene expression showed a mild upregulation at 165 DPF in both tissues. Thus, exposure to EE2 during early development affected distinctly the IGF system in tilapia immune organs. It led to lasting impairment of spleen growth and differentiation that can be attributed to an interaction of EE2 with IGF-I and, less pronouncedly, IGF

IGF-1R mRNA expression is increased in obese children.

PubMed

Ricco, Rafaela Cristina; Ricco, Rubens Garcia; Queluz, Mariangela Carletti; de Paula, Mariana Teresa Sarti; Atique, Patricia Volpon; Custódio, Rodrigo José; Tourinho Filho, Hugo; Del Roio Liberatori, Raphael; Martinelli, Carlos Eduardo

2018-04-01

Obese children are often taller than age-matched subjects. Reports on GH and IGF-I levels in obese individuals are controversial, with normal and reduced GH-IGF-I levels having been reported in this group of patients. Thus, the aim of this study was to analyse insulin-like growth factor type 1 receptor (IGF-IR) mRNA expression in obese children. Forty-seven pre-pubertal children were included in this study: 29 were obese and taller than their target height, and 18 were normal eutrophic controls. Fasting blood samples were collected for IGF-IR mRNA expression in isolated lymphocytes and serum IGF-I, ALS, IGFBP-3, and IGFBP-1 concentration analysis. Relative IGF-IR gene expression (2 -ΔΔCT ) was significantly (P=0.025) higher in obese children (median 1.87) than in controls (1.15). Fourteen of the 29 obese subjects showed 2 -ΔΔCT values greater than or equal to 2, while only 2 individuals in the control group showed values above 2 (P=0.01). Obese children showed significantly (P=0.01) higher IGF-I concentrations than the control group (237ng/ml and 144ng/ml, respectively). Among obese patients, 65.5% had IGF-I values above the 75 percentile of the control group (P=0.02). ALS concentration was significantly (P=0.04) higher in the obese group, while IGFBP-3 levels were similar in obese and control children. IGFBP-1 concentration was lower in obese children, while insulin levels and HOMA-IR index were higher than in controls. The higher IGF-IR mRNA expression observed in obese children, associated with the higher IGF-I and ALS and the lower IGFBP-1 levels, suggest that the higher stature observed in these children may be due to increased IGF-I bioactivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Maternal residential air pollution and placental imprinted gene expression.

PubMed

Kingsley, Samantha L; Deyssenroth, Maya A; Kelsey, Karl T; Awad, Yara Abu; Kloog, Itai; Schwartz, Joel D; Lambertini, Luca; Chen, Jia; Marsit, Carmen J; Wellenius, Gregory A

2017-11-01

Maternal exposure to air pollution is associated with reduced fetal growth, but its relationship with expression of placental imprinted genes (important regulators of fetal growth) has not yet been studied. To examine relationships between maternal residential air pollution and expression of placental imprinted genes in the Rhode Island Child Health Study (RICHS). Women-infant pairs were enrolled following delivery between 2009 and 2013. We geocoded maternal residential addresses at delivery, estimated daily levels of fine particulate matter (PM 2.5 ; n=355) and black carbon (BC; n=336) using spatial-temporal models, and estimated residential distance to nearest major roadway (n=355). Using linear regression models we investigated the associations between each exposure metric and expression of nine candidate genes previously associated with infant birthweight in RICHS, with secondary analyses of a panel of 108 imprinted genes expressed in the placenta. We also explored effect measure modification by infant sex. PM 2.5 and BC were associated with altered expression for seven and one candidate genes, respectively, previously linked with birthweight in this cohort. Adjusting for multiple comparisons, we found that PM 2.5 and BC were associated with changes in expression of 41 and 12 of 108 placental imprinted genes, respectively. Infant sex modified the association between PM 2.5 and expression of CHD7 and between proximity to major roadways and expression of ZDBF2. We found that maternal exposure to residential PM 2.5 and BC was associated with changes in placental imprinted gene expression, which suggests a plausible line of investigation of how air pollution affects fetal growth and development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

PubMed

Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

2017-08-01

We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

Transcription factor ZBED6 mediates IGF2 gene expression by regulating promoter activity and DNA methylation in myoblasts

USDA-ARS?s Scientific Manuscript database

Zinc finger, BED-type containing 6 (ZBED6) is an important transcription factor in placental mammals, affecting development, cell proliferation and growth. In this study, we found that the expression of the ZBED6 and IGF2 were up regulated during C2C12 differentiation. The IGF2 expression levels wer...

Evolutionary genetic models of the ovarian time bomb hypothesis for the evolution of genomic imprinting.

PubMed Central

Weisstein, Anton E; Feldman, Marcus W; Spencer, Hamish G

2002-01-01

At a small number of loci in eutherian mammals, only one of the two copies of a gene is expressed; the other is silenced. Such loci are said to be "imprinted," with some having the maternally inherited allele inactivated and others showing paternal inactivation. Several hypotheses have been proposed to explain how such a genetic system could evolve in the face of the selective advantages of diploidy. In this study, we examine the "ovarian time bomb" hypothesis, which proposes that imprinting arose through selection for reduced risk of ovarian trophoblastic disease in females. We present three evolutionary genetic models that incorporate both this selection pressure and the effect of deleterious mutations to elucidate the conditions under which imprinting could evolve. Our findings suggest that the ovarian time bomb hypothesis can explain why some growth-enhancing genes active in early embryogenesis [e.g., mouse insulin-like growth factor 2 (Igf2)] have evolved to be maternally rather than paternally inactive and why the opposite imprinting status has evolved at some growth-inhibiting loci [e.g., mouse insulin-like growth factor 2 receptor (Igf2r)]. PMID:12242251

Matrix metalloproteinase-1 facilitates MSC migration via cleavage of IGF-2/IGFBP2 complex.

PubMed

Guan, Shou P; Lam, Alan T L; Newman, Jennifer P; Chua, Kevin L M; Kok, Catherine Y L; Chong, Siao T; Chua, Melvin L K; Lam, Paula Y P

2018-01-01

The specific mechanism underlying the tumor tropism of human mesenchymal stem cells (MSCs) for cancer is not well defined. We previously showed that the migration potential of MSCs correlated with the expression and protease activity of matrix metalloproteinase (MMP)-1. Furthermore, highly tumor-tropic MSCs expressed higher levels of MMP-1 and insulin-like growth factor (IGF)-2 than poorly migrating MSCs. In this study, we examined the functional roles of IGF-2 and MMP-1 in mediating the tumor tropism of MSCs. Exogenous addition of either recombinant IGF-2 or MMP-1 could stimulate MSC migration. The correlation between IGF-2, MMP-1 expression, and MSC migration suggests that MMP-1 may play a role in regulating MSC migration via the IGF-2 signaling cascade. High concentrations of IGF binding proteins (IGFBPs) can inhibit IGF-stimulated functions by blocking its binding to its receptors and proteolysis of IGFBP is an important mechanism for the regulation of IGF signaling. We thus hypothesized that MMP-1 acts as an IGFBP2 proteinase, resulting in the cleavage of IGF-2/IGFBP2 complex and extracellular release of free IGF-2. Indeed, our results showed that conditioned media from highly migrating MSCs, which expressed high levels of MMP-1, cleaved the IGF-2/IGFBP2 complex. Taken together, these results showed that the MMP-1 secreted by highly tumor-tropic MSCs cleaved IGF-2/IGFBP2 complex. Free IGF-2 released from the complex may facilitate MSC migration toward tumor.

Potential roles for transposable elements in creating imprinted expression.

PubMed

Anderson, Sarah N; Springer, Nathan M

2018-04-01

Changes in gene expression can have profound effects on phenotype. Nature has provided many complex patterns of gene regulation such as imprinting. Imprinted genes exhibit differences in the expression of the maternal and paternal alleles, even though they reside in the same nucleus with access to the same trans-acting factors. Significant attention has been focused on the potential reasons that imprinted expression could be beneficial and stabilized by selection. However, less attention has focused on understanding how imprinted expression might arise or decay. We discuss the evidence for frequent turnover of imprinted expression based on evolutionary analyses in plants and the potential role for transposable elements (TEs) in creating imprinted expression patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

An HMGA2-IGF2BP2 Axis Regulates Myoblast Proliferation and Myogenesis

PubMed Central

Li, Zhizhong; Gilbert, Jason A.; Zhang, Yunyu; Zhang, Minsi; Qiu, Qiong; Ramanujan, Krishnan; Shavlakadze, Tea; Eash, John K.; Scaramozza, Annarita; Goddeeris, Matthew M.; Kirsch, David G.; Campbell, Kevin P.; Brack, Andrew S.; Glass, David J.

2013-01-01

Summary A group of genes that are highly and specifically expressed in proliferating skeletal myoblasts during myogenesis was identified. Expression of one of these genes, Hmga2, increases coincident with satellite cell activation, and later its expression significantly declines correlating with fusion of myoblasts into myotubes. Hmga2 knockout mice exhibit impaired muscle development and reduced myoblast proliferation, while overexpression of HMGA2 promotes myoblast growth. This perturbation in proliferation can be explained by the finding that HMGA2 directly regulates the RNA-binding protein IGF2BP2. Add-back of IGF2BP2 rescues the phenotype. IGF2BP2 in turn binds to and controls the translation of a set of mRNAs, including c-myc, Sp1, and Igf1r. These data demonstrate that the HMGA2-IGF2BP2 axis functions as a key regulator of satellite cell activation and therefore skeletal muscle development. PMID:23177649

An HMGA2-IGF2BP2 axis regulates myoblast proliferation and myogenesis.

PubMed

Li, Zhizhong; Gilbert, Jason A; Zhang, Yunyu; Zhang, Minsi; Qiu, Qiong; Ramanujan, Krishnan; Shavlakadze, Tea; Eash, John K; Scaramozza, Annarita; Goddeeris, Matthew M; Kirsch, David G; Campbell, Kevin P; Brack, Andrew S; Glass, David J

2012-12-11

A group of genes that are highly and specifically expressed in proliferating skeletal myoblasts during myogenesis was identified. Expression of one of these genes, Hmga2, increases coincident with satellite cell activation, and later its expression significantly declines correlating with fusion of myoblasts into myotubes. Hmga2 knockout mice exhibit impaired muscle development and reduced myoblast proliferation, while overexpression of HMGA2 promotes myoblast growth. This perturbation in proliferation can be explained by the finding that HMGA2 directly regulates the RNA-binding protein IGF2BP2. Add-back of IGF2BP2 rescues the phenotype. IGF2BP2 in turn binds to and controls the translation of a set of mRNAs, including c-myc, Sp1, and Igf1r. These data demonstrate that the HMGA2-IGF2BP2 axis functions as a key regulator of satellite cell activation and therefore skeletal muscle development. Copyright © 2012 Elsevier Inc. All rights reserved.

IGF2 DNA methylation is a modulator of newborn's fetal growth and development.

PubMed

St-Pierre, Julie; Hivert, Marie-France; Perron, Patrice; Poirier, Paul; Guay, Simon-Pierre; Brisson, Diane; Bouchard, Luigi

2012-10-01

The insulin-like growth factor 2 (IGF2) gene, located within a cluster of imprinted genes on chromosome 11p15, encodes a fetal and placental growth factor affecting birth weight. DNA methylation variability at the IGF2 gene locus has been previously reported but its consequences on fetal growth and development are still mostly unknown in normal pediatric population. We collected one hundred placenta biopsies from 50 women with corresponding maternal and cord blood samples and measured anthropometric indices, blood pressure and metabolic phenotypes using standardized procedures. IGF2/H19 DNA methylation and IGF2 circulating levels were assessed using sodium bisulfite pyrosequencing and ELISA, respectively. Placental IGF2 (DMR0 and DMR2) DNA methylation levels were correlated with newborn's fetal growth indices, such as weight, and with maternal IGF2 circulating concentration at the third trimester of pregnancy, whereas H19 (DMR) DNA methylation levels were correlated with IGF2 levels in cord blood. The maternal genotype of a known IGF2/H19 polymorphism (rs2107425) was associated with birth weight. Taken together, we showed that IGF2/H19 epigenotype and genotypes independently account for 31% of the newborn's weight variance. No association was observed with maternal diabetic status, glucose concentrations or prenatal maternal body mass index. This is the first study showing that DNA methylation at the IGF2/H19 genes locus may act as a modulator of IGF2 newborn's fetal growth and development within normal range. IGF2/H19 DNA methylation could represent a cornerstone in linking birth weight and fetal metabolic programming of late onset obesity.

The testis-specific factor CTCFL cooperates with the protein methyltransferase PRMT7 in H19 imprinting control region methylation.

PubMed

Jelinic, Petar; Stehle, Jean-Christophe; Shaw, Phillip

2006-10-01

Expression of imprinted genes is restricted to a single parental allele as a result of epigenetic regulation-DNA methylation and histone modifications. Igf2/H19 is a reciprocally imprinted locus exhibiting paternal Igf2 and maternal H19 expression. Their expression is regulated by a paternally methylated imprinting control region (ICR) located between the two genes. Although the de novo DNA methyltransferases have been shown to be necessary for the establishment of ICR methylation, the mechanism by which they are targeted to the region remains unknown. We demonstrate that CTCFL/BORIS, a paralog of CTCF, is an ICR-binding protein expressed during embryonic male germ cell development, coinciding with the timing of ICR methylation. PRMT7, a protein arginine methyltransferase with which CTCFL interacts, is also expressed during embryonic testis development. Symmetrical dimethyl arginine 3 of histone H4, a modification catalyzed by PRMT7, accumulates in germ cells during this developmental period. This modified histone is also found enriched in both H19 ICR and Gtl2 differentially methylated region (DMR) chromatin of testis by chromatin immunoprecipitation (ChIP) analysis. In vitro studies demonstrate that CTCFL stimulates the histone-methyltransferase activity of PRMT7 via interactions with both histones and PRMT7. Finally, H19 ICR methylation is demonstrated by nuclear co-injection of expression vectors encoding CTCFL, PRMT7, and the de novo DNA methyltransferases, Dnmt3a, -b and -L, in Xenopus oocytes. These results suggest that CTCFL and PRMT7 may play a role in male germline imprinted gene methylation.

The Testis-Specific Factor CTCFL Cooperates with the Protein Methyltransferase PRMT7 in H19 Imprinting Control Region Methylation

PubMed Central

Jelinic, Petar; Stehle, Jean-Christophe; Shaw, Phillip

2006-01-01

Expression of imprinted genes is restricted to a single parental allele as a result of epigenetic regulation—DNA methylation and histone modifications. Igf2/H19 is a reciprocally imprinted locus exhibiting paternal Igf2 and maternal H19 expression. Their expression is regulated by a paternally methylated imprinting control region (ICR) located between the two genes. Although the de novo DNA methyltransferases have been shown to be necessary for the establishment of ICR methylation, the mechanism by which they are targeted to the region remains unknown. We demonstrate that CTCFL/BORIS, a paralog of CTCF, is an ICR-binding protein expressed during embryonic male germ cell development, coinciding with the timing of ICR methylation. PRMT7, a protein arginine methyltransferase with which CTCFL interacts, is also expressed during embryonic testis development. Symmetrical dimethyl arginine 3 of histone H4, a modification catalyzed by PRMT7, accumulates in germ cells during this developmental period. This modified histone is also found enriched in both H19 ICR and Gtl2 differentially methylated region (DMR) chromatin of testis by chromatin immunoprecipitation (ChIP) analysis. In vitro studies demonstrate that CTCFL stimulates the histone-methyltransferase activity of PRMT7 via interactions with both histones and PRMT7. Finally, H19 ICR methylation is demonstrated by nuclear co-injection of expression vectors encoding CTCFL, PRMT7, and the de novo DNA methyltransferases, Dnmt3a, -b and -L, in Xenopus oocytes. These results suggest that CTCFL and PRMT7 may play a role in male germline imprinted gene methylation. PMID:17048991

Investigation of PAX3/7-FKHR fusion genes and IGF2 gene expression in rhabdomyosarcoma tumors.

PubMed

de Souza, Robson Ramos; Oliveira, Indhira Dias; Caran, Eliana Maria Monteiro; Alves, Maria Teresa de Seixas; Abib, Simone; Toledo, Silvia Regina Caminada

2012-12-01

The purpose of our study was to investigate the prevalence of the PAX3/7-FKHR fusion genes and quantify the IGF2 gene expression in rhabdomyosarcoma (RMS) samples. Soft tissue sarcomas account 5% of childhood cancers and 50% of them are RMS. Morphological evaluation of pediatric RMS has defined two histological subtypes, embryonal (ERMS) and alveolar (ARMS). Chromosomal analyses have demonstrated two translocations associated with ARMS, resulting in the PAX3/7-FKHR rearrangements. Reverse transcriptase-polymerase chain reaction (RT-PCR) is extremely useful in the diagnosis of ARMS positive for these rearrangements. Additionally, several studies have shown a significant involvement of IGF pathway in the pathogenesis of RMS. The presence of PAX3/7-FKHR gene fusions was studied in 25 RMS samples from patients attending the IOP-GRAACC/UNIFESP and three RMS cell lines by RT-PCR. IGF2 gene expression was quantified by qPCR and related with clinic pathological parameters. Of the 25 samples, nine (36%) were ARMS and 16 (64%) were ERMS. PAX3/7-FKHR gene fusions expression was detected in 56% of ARMS tumor samples. IGF2 overexpression was observed in 80% of samples and could indicate an important role of this pathway in RMS biology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort

PubMed Central

2013-01-01

Background Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene. Methods We examined DNA from umbilical cord blood leukocytes from 79 newborns, born between July 2005 and November 2006 at Duke University Hospital, Durham, NC. Their mothers participated in the Newborn Epigenetics Study (NEST) during pregnancy. Parental characteristics were obtained via standardized questionnaires and medical records. DNA methylation patterns at two DMRs were analyzed by bisulfite pyrosequencing; one DMR upstream of IGF2 (IGF2 DMR), and one DMR upstream of the neighboring H19 gene (H19 DMR). Multiple regression models were used to determine potential associations between the offspring's DNA methylation patterns and parental obesity before conception. Obesity was defined as body mass index (BMI) ≥30 kg/m2. Results Hypomethylation at the IGF2 DMR was associated with paternal obesity. Even after adjusting for several maternal and newborn characteristics, we observed a persistent inverse association between DNA methylation in the offspring and paternal obesity (β-coefficient was -5.28, P = 0.003). At the H19 DMR, no significant associations were detected between methylation patterns and paternal obesity. Our data suggest an increase in DNA methylation at the IGF2 and H19 DMRs among newborns from obese

Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort.

PubMed

Soubry, Adelheid; Schildkraut, Joellen M; Murtha, Amy; Wang, Frances; Huang, Zhiqing; Bernal, Autumn; Kurtzberg, Joanne; Jirtle, Randy L; Murphy, Susan K; Hoyo, Cathrine

2013-02-06

Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene. We examined DNA from umbilical cord blood leukocytes from 79 newborns, born between July 2005 and November 2006 at Duke University Hospital, Durham, NC. Their mothers participated in the Newborn Epigenetics Study (NEST) during pregnancy. Parental characteristics were obtained via standardized questionnaires and medical records. DNA methylation patterns at two DMRs were analyzed by bisulfite pyrosequencing; one DMR upstream of IGF2 (IGF2 DMR), and one DMR upstream of the neighboring H19 gene (H19 DMR). Multiple regression models were used to determine potential associations between the offspring's DNA methylation patterns and parental obesity before conception. Obesity was defined as body mass index (BMI) ≥30 kg/m². Hypomethylation at the IGF2 DMR was associated with paternal obesity. Even after adjusting for several maternal and newborn characteristics, we observed a persistent inverse association between DNA methylation in the offspring and paternal obesity (β-coefficient was -5.28, P = 0.003). At the H19 DMR, no significant associations were detected between methylation patterns and paternal obesity. Our data suggest an increase in DNA methylation at the IGF2 and H19 DMRs among newborns from obese mothers, but a larger study

IGF2 DNA methylation is a modulator of newborn’s fetal growth and development

PubMed Central

St-Pierre, Julie; Hivert, Marie-France; Perron, Patrice; Poirier, Paul; Guay, Simon-Pierre; Brisson, Diane; Bouchard, Luigi

2012-01-01

The insulin-like growth factor 2 (IGF2) gene, located within a cluster of imprinted genes on chromosome 11p15, encodes a fetal and placental growth factor affecting birth weight. DNA methylation variability at the IGF2 gene locus has been previously reported but its consequences on fetal growth and development are still mostly unknown in normal pediatric population. We collected one hundred placenta biopsies from 50 women with corresponding maternal and cord blood samples and measured anthropometric indices, blood pressure and metabolic phenotypes using standardized procedures. IGF2/H19 DNA methylation and IGF2 circulating levels were assessed using sodium bisulfite pyrosequencing and ELISA, respectively. Placental IGF2 (DMR0 and DMR2) DNA methylation levels were correlated with newborn’s fetal growth indices, such as weight, and with maternal IGF2 circulating concentration at the third trimester of pregnancy, whereas H19 (DMR) DNA methylation levels were correlated with IGF2 levels in cord blood. The maternal genotype of a known IGF2/H19 polymorphism (rs2107425) was associated with birth weight. Taken together, we showed that IGF2/H19 epigenotype and genotypes independently account for 31% of the newborn’s weight variance. No association was observed with maternal diabetic status, glucose concentrations or prenatal maternal body mass index. This is the first study showing that DNA methylation at the IGF2/H19 genes locus may act as a modulator of IGF2 newborn’s fetal growth and development within normal range. IGF2/H19 DNA methylation could represent a cornerstone in linking birth weight and fetal metabolic programming of late onset obesity. PMID:22907587

Placental expression of 2,3 bisphosphoglycerate mutase in IGF-II knock out mouse: correlation of circulating maternal 2,3 bisphosphoglycerate and fetal growth.

PubMed

Gu, M; Pritlove, D C; Boyd, C A R; Vatish, M

2009-10-01

Bisphosphoglycerate mutase (BPGM) catalyses the formation of 2,3 bisphosphoglycerate (BPG) a ligand of haemoglobin. BPG facilitates liberation of oxygen from haemoglobin at low oxygen tension enabling efficient delivery of oxygen to tissues. We describe expression of BPGM in mouse labyrinthine trophoblasts, located at the maternal-placental interface. Expression is lower in placentae of igf2(+/-) knockout mice, a widely used model of growth restriction, compared to wild type placentae. Circulating maternal BPG increased throughout gestation but this increase was less in wt mothers carrying igf2(+/-) pups than in those carrying exclusively wt pups. This reduction was observed well before term and may contribute to the low birth weight of igf2(+/-) pups. Strikingly, we also measured reductions of fetal and placental weight in wt littermates of igf2(+/-) pups compared to pups developing in an exclusively wt environment. These data suggest that placental expression of BPGM can influence maternal BPG concentrations and supports a hypothesis under which BPG synthesized in the placenta may act on maternal haemoglobin to enhance delivery of oxygen to the developing fetus.

The hepatic Igf2/H19 locus is not altered in 1-day old pups born to obese-prone Sprague-Dawley rats fed a low protein diet containing adequate folic acid

USDA-ARS?s Scientific Manuscript database

Gong et al. (Epigenetics, 2010) found, using diets low in folic acid, that compared to an 18% protein diet a 9% protein diet fed to pregnant Sprague-Dawley rats resulted in increased Igf2 and H19 gene expression in the liver of day 0 male offspring. In addition DNA methylation in the Imprinting Cont...

Comparisons of mRNA expression for insulin-like growth factor (IGF) type 2 receptor (IGF2R) and IGF-1 in small ovarian follicles between cattle selected and not selected for twin ovulations

USDA-ARS?s Scientific Manuscript database

Both IGF-1 and -2 stimulate ovarian follicular cell proliferation and antral follicle development. Actions of IGF-1 and -2 are mediated through the IGF type 1 receptor, whereas binding of IGF-2 to the IGF2R results in its degradation. Information on the role of IGF2R in regulating bovine follicula...

A search for imprinted quantitative trait loci (QTLs) for birth weight

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandya, A.; Llewellyn, B.; Schieken, R.

1994-09-01

Previous studies have generally provided strong evidence that maternal effects are a much more important determinant of birth weight than the genes of the fetus. In the past, these findings have been interpreted as reflecting a genetically determined maternal constraint on fetal growth. However, the recognition that the expression of a gene can be influenced by its parental origin has provided an alternative explanation for apparent maternal effects. In the mouse, a growing number of imprinted genes have been identified which can profoundly influence birth weight or body size including IGF-1, IGF-2, and their respective receptor loci. To determine whethermore » any of the loci are QTLs for body size in man, we have used parental typing data to classify dizygotic twins according to their identity by descent (IBD) for polymorphic markers at or near the candidate loci. The contrast between the correlations of DZ pairs sharing both alleles IBD and no alleles IBD can provide evidence for a candidate gene effect while the contrast between twins sharing one maternal or one paternal allele IBD can provide evidence for any effect of imprinting that may exist at the locus. Finally, the inclusion of data on MZ twins in an overall analysis permits the resolution of the imprinting and marker gene effects from other sources of genetic and environmental variation. We have applied this model to birth weight data on 181 pairs of twins who were classified according to their allele sharing at the IGF-1 locus. In keeping with other observations, the data show no evidence that the IGF-1 locus is imprinted in man. Although our results are consistent with the possibility that this locus may account for 15-20% of the genetic variation, the apparent effect is not statistically significant. Partitioned twin analysis appears to be a useful method for detecting the effects of specific candidate gene on continuously distributed traits.« less

The nucleotides responsible for the direct physical contact between the chromatin insulator protein CTCF and the H19 imprinting control region manifest parent of origin-specific long-distance insulation and methylation-free domains

PubMed Central

Pant, Vinod; Mariano, Piero; Kanduri, Chandrasekhar; Mattsson, Anita; Lobanenkov, Victor; Heuchel, Rainer; Ohlsson, Rolf

2003-01-01

The repression of the maternally inherited Igf2 allele has been proposed to depend on a methylation-sensitive chromatin insulator organized by the 11 zinc finger protein CTCF at the H19 imprinting control region (ICR). Here we document that point mutations of the nucleotides in physical contact with CTCF within the endogenous H19 ICR lead to loss of CTCF binding and Igf2 imprinting only when passaged through the female germline. This effect is accompanied by a significant loss of methylation protection of the maternally derived H19 ICR. Because CTCF interacts with other imprinting control regions, it emerges as a central factor responsible for interpreting and propagating gamete-derived epigenetic marks and for organizing epigenetically controlled expression domains. PMID:12629040

In vitro fertilization alters growth and expression of Igf2/H19 and their epigenetic mechanisms in the liver and skeletal muscle of newborn and elder mice.

PubMed

Le, Fang; Wang, Li Ya; Wang, Ning; Li, Lei; Li, Le Jun; Zheng, Ying Ming; Lou, Hang Ying; Liu, Xiao Zhen; Xu, Xiang Rong; Sheng, Jian Zhong; Huang, He Feng; Jin, Fan

2013-03-01

Epidemiological studies have reported a higher incidence of growth disorders among newborns conceived by in vitro fertilization (IVF), suggesting that IVF may be disruptive to the process of embryonic and fetal growth. However, the long-term effects of IVF on the growth and molecular mechanisms remain unclear. Therefore, we evaluated the body weight of IVF mice from birth to the age of 1.5 yr. In addition, we analyzed gene expression of insulin-like growth factor 2 (Igf2), H19, Igf2 receptor (Igf2r), and miR-483 and their DNA methylation status using real-time quantitative PCR, Western blot, and pyrosequencing. The results showed that when compared with the in vivo group, the body weight of IVF mice was significantly higher at birth, but lower at 3 wk; in addition, gene expression of Igf2 was significantly up-regulated, with down-regulated expression of H19 and miR-483 in both liver and skeletal muscle. At the same time, there were significant differences in the DNA methylation rates of Igf2/H19 differentially methylated regions (DMRs) and the IGF2 protein expression between the two groups. In the IVF treatment group, the differences in growth and expression disappeared at 10 wk. However, at 1.5 yr of age, aberrant expressions of Igf2/H19, Igf2r, and miR-483 and changes in DNA methylation rates in the liver or skeletal muscle were again observed in IVF mice. Our results indicate that IVF causes alterations in mouse growth during the postnatal periods that may be associated with alterations in Igf2/H19 expression and likely involve the regulation of miR-483 and the methylation status of Igf2/H19 DMRs.

Differential regulation of genomic imprinting by TET proteins in embryonic stem cells.

PubMed

Liu, Lizhi; Mao, Shi-Qing; Ray, Chelsea; Zhang, Yu; Bell, Fong T; Ng, Sheau-Fang; Xu, Guo-Liang; Li, Xiajun

2015-09-01

TET proteins have been found to play an important role in active demethylation at CpG sites in mammals. There are some reports implicating their functions in removal of DNA methylation imprint at the imprinted regions in the germline. However, it is not well established whether TET proteins can also be involved in demethylation of DNA methylation imprint in embryonic stem (ES) cells. Here we report that loss of TET proteins caused a significant increase in DNA methylation at the Igf2-H19 imprinted region in ES cells. We also observed a variable increase in DNA methylation at the Peg1 imprinted region in the ES clones devoid of TET proteins, in particular in the differentiated ES cells. By contrast, we did not observe a significant increase of DNA methylation imprint at the Peg3, Snrpn and Dlk1-Dio3 imprinted regions in ES cells lacking TET proteins. Interestingly, loss of TET proteins did not result in a significant increase of DNA methylation imprint at the Igf2-H19 and Peg1 imprinted regions in the embryoid bodies (EB). Therefore, TET proteins seem to be differentially involved in maintaining DNA methylation imprint at a subset of imprinted regions in ES cells and EBs. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

BRCA1 is expressed in uterine serous carcinoma (USC) and controls insulin-like growth factor I receptor (IGF-IR) gene expression in USC cell lines.

PubMed

Amichay, Keren; Kidron, Debora; Attias-Geva, Zohar; Schayek, Hagit; Sarfstein, Rive; Fishman, Ami; Werner, Haim; Bruchim, Ilan

2012-06-01

The insulin-like growth factor I receptor (IGF-IR) and BRCA1 affect cell growth and apoptosis. Little information is available about BRCA1 activity on the IGF signaling pathway. This study evaluated the effect of BRCA1 on IGF-IR expression. BRCA1 and IGF-IR immunohistochemistry on archival tissues (35 uterine serous carcinomas [USCs] and 17 metastases) were performed. USPC1 and USPC2 cell lines were transiently cotransfected with an IGF-IR promoter construct driving a luciferase reporter gene and a BRCA1 expression plasmid. Endogenous IGF-IR levels were evaluated by Western immunoblotting. We found high BRCA1 and IGF-IR protein expression in primary and metastatic USC tumors. All samples were immunostained for BRCA1-71% strongly stained; and 33/35 (94%) were stained positive for IGF-IR-2 (6%) strongly stained. No difference in BRCA1 and IGF-IR staining intensity was noted between BRCA1/2 mutation carriers and noncarriers. Metastatic tumors stained more intensely for BRCA1 than did the primary tumor site (P = 0.041) and with borderline significance for IGF-IR (P = 0.069). BRCA1 and IGF-IR staining did not correlate to survival. BRCA1 expression led to 35% and 54% reduction in IGF-IR promoter activity in the USPC1 and USCP2 cell lines, respectively. Western immunoblotting showed a decline in phosphorylated IGF-IR and phosphorylated AKT in both transiently and stably transfected cells. BRCA1 and IGF-IR are highly expressed in USC tumors. BRCA1 suppresses IGF-IR gene expression and activity. These findings suggest a possible biological link between the BRCA1 and the IGF-I signaling pathways in USC. The clinical implications of this association need to be explored.

Novel role of cannabinoid receptor 2 in inhibiting EGF/EGFR and IGF-I/IGF-IR pathways in breast cancer.

PubMed

Elbaz, Mohamad; Ahirwar, Dinesh; Ravi, Janani; Nasser, Mohd W; Ganju, Ramesh K

2017-05-02

Breast cancer is the second leading cause of cancer deaths among women. Cannabinoid receptor 2 (CNR2 or CB2) is an integral part of the endocannabinoid system. Although CNR2 is highly expressed in the breast cancer tissues as well as breast cancer cell lines, its functional role in breast tumorigenesis is not well understood. We observed that estrogen receptor-α negative (ERα-) breast cancer cells highly express epidermal growth factor receptor (EGFR) as well as insulin-like growth factor-I receptor (IGF-IR). We also observed IGF-IR upregulation in ERα+ breast cancer cells. In addition, we found that higher CNR2 expression correlates with better recurrence free survival in ERα- and ERα+ breast cancer patients. Therefore, we analyzed the role of CNR2 specific agonist (JWH-015) on EGF and/or IGF-I-induced tumorigenic events in ERα- and ERα+ breast cancers. Our studies showed that CNR2 activation inhibited EGF and IGF-I-induced migration and invasion of ERα+ and ERα- breast cancer cells. At the molecular level, JWH-015 inhibited EGFR and IGF-IR activation and their downstream targets STAT3, AKT, ERK, NF-kB and matrix metalloproteinases (MMPs). In vivo studies showed that JWH-015 significantly reduced breast cancer growth in ERα+ and ERα- breast cancer mouse models. Furthermore, we found that the tumors derived from JWH-015-treated mice showed reduced activation of EGFR and IGF-IR and their downstream targets. In conclusion, we show that CNR2 activation suppresses breast cancer through novel mechanisms by inhibiting EGF/EGFR and IGF-I/IGF-IR signaling axes.

IGF-1 attenuates LPS induced pro-inflammatory cytokines expression in buffalo (Bubalus bubalis) granulosa cells.

PubMed

Onnureddy, K; Ravinder; Onteru, Suneel Kumar; Singh, Dheer

2015-03-01

Interaction between immune and endocrine system is a diverse process influencing cellular function and homeostasis in animals. Negative energy balance (NEB) during postpartum period in dairy animals usually suppresses these systems resulting in reproductive tract infection and infertility. These negative effects could be due to competition among endocrine and immune signaling pathways for common signaling molecules. The present work studied the effect of IGF-1 (50 ng/ml) on LPS (1 μg/ml) mediated pro-inflammatory cytokine expression (IL-1β, TNF-α, IL-6) and aromatase (CYP19A1) genes' expressions as well as proliferation of buffalo granulosa cells. The crosstalk between LPS and IGF-1 was also demonstrated through studying the activities of downstream signaling molecules (ERK1/2, Akt, NF-κB) by western blot and immunostaining. Gene expression analysis showed that IGF-1 significantly reduced the LPS induced expression of IL-1β, TNF-α and IL-6. LPS alone inhibited the CYP19A1 expression. However, co-treatment with IGF-1 reversed the inhibitory effect of LPS on CYP19A1 expression. LPS alone did not affect granulosa cell proliferation, but co-treatment with IGF-1, and IGF-1 alone enhanced the proliferation. Western blot results demonstrated that LPS caused the nuclear translocation of the NF-κB and increased the phosphorylation of ERK1/2 and Akt maximum at 15 min and 60 min, respectively. Nonetheless, co-treatment with IGF-1 delayed LPS induced phosphorylation of ERK1/2 (peak at 120 min), while promoting early Akt phosphorylation (peak at 5 min) with no effect on NF-κB translocation. Overall, IGF-1 delayed and reversed the effects of LPS, suggesting that high IGF-1 levels may combat infection during critical periods like NEB in postpartum dairy animals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Extensive investigation of the IGF2/H19 imprinting control region reveals novel OCT4/SOX2 binding site defects associated with specific methylation patterns in Beckwith-Wiedemann syndrome.

PubMed

Abi Habib, Walid; Azzi, Salah; Brioude, Frédéric; Steunou, Virginie; Thibaud, Nathalie; Das Neves, Cristina; Le Jule, Marilyne; Chantot-Bastaraud, Sandra; Keren, Boris; Lyonnet, Stanislas; Michot, Caroline; Rossi, Massimiliano; Pasquier, Laurent; Gicquel, Christine; Rossignol, Sylvie; Le Bouc, Yves; Netchine, Irène

2014-11-01

Isolated gain of methylation (GOM) at the IGF2/H19 imprinting control region 1 (ICR1) accounts for about 10% of patients with BWS. A subset of these patients have genetic defects within ICR1, but the frequency of these defects has not yet been established in a large cohort of BWS patients with isolated ICR1 GOM. Here, we carried out a genetic analysis in a large cohort of 57 BWS patients with isolated ICR1 GOM and analyzed the methylation status of the entire domain. We found a new point mutation in two unrelated families and a 21 bp deletion in another unrelated child, both of which were maternally inherited and affected the OCT4/SOX2 binding site in the A2 repeat of ICR1. Based on data from this and previous studies, we estimate that cis genetic defects account for about 20% of BWS patients with isolated ICR1 GOM. Methylation analysis at eight loci of the IGF2/H19 domain revealed that sites surrounding OCT4/SOX2 binding site mutations were fully methylated and methylation indexes declined as a function of distance from these sites. This was not the case in BWS patients without genetic defects identified. Thus, GOM does not spread uniformly across the IGF2/H19 domain, suggesting that OCT4/SOX2 protects against methylation at local sites. These findings add new insights to the mechanism of the regulation of the ICR1 domain. Our data show that mutations and deletions within ICR1 are relatively common. Systematic identification is therefore necessary to establish appropriate genetic counseling for BWS patients with isolated ICR1 GOM. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Dietary betaine supplementation to gestational sows enhances hippocampal IGF2 expression in newborn piglets with modified DNA methylation of the differentially methylated regions.

PubMed

Li, Xi; Sun, Qinwei; Li, Xian; Cai, Demin; Sui, Shiyan; Jia, Yimin; Song, Haogang; Zhao, Ruqian

2015-10-01

The adequate supply of methyl donors is critical for the normal development of brain. The purpose of the present study was to investigate the effects of maternal betaine supplementation on hippocampal gene expression in neonatal piglets and to explore the possible mechanisms. Gestational sows were fed control or betaine-supplemented (3 g/kg) diets throughout the pregnancy. Immediately after birth, male piglets were killed, and the hippocampus was dissected for analyses. The mRNA abundance was determined by reverse transcription real-time polymerase chain reaction. Protein content was measured by Western blot, and DNA methylation was detected by methylated DNA immunoprecipitation assay. Prenatal betaine supplementation did not alter the body weight or the hippocampus weight, but increased the hippocampal DNA content as well as the mRNA expression of proliferation-related genes. Prenatal betaine supplementation increased serum level of methionine (P < 0.05) and up-regulated (P < 0.05) the mRNA and protein expression of betaine-homocysteine methyltransferase, glycine N-methyltransferase and DNA methyltransferase 1 in the neonatal hippocampus. Hippocampal expression of insulin growth factor II (IGF2) and its receptors IGF1R and IGF2R were all significantly up-regulated (P < 0.05) in betaine-treated group, together with a significant activation (P < 0.01) of the downstream extracellular signal-regulated kinase 1/2. Moreover, the differentially methylated region (DMR) 1 and 2 on IGF2 locus was found to be hypermethylated (P < 0.05) in the hippocampus of betaine-treated piglets. These results indicate that maternal betaine supplementation enhances betaine/methionine metabolism and DNA methyltransferase expression, causes hypermethylation of DMR on IGF2 gene, which was associated with augmented expression of IGF2 and cell proliferation/anti-apoptotic markers in the hippocampus of neonatal piglets.

Relationship between serum IGF-1 and skeletal muscle IGF-1 mRNA expression to phosphocreatine recovery after exercise in obese men with reduced GH.

PubMed

Hamarneh, Sulaiman R; Murphy, Caitlin A; Shih, Cynthia W; Frontera, Walter; Torriani, Martin; Irazoqui, Javier E; Makimura, Hideo

2015-02-01

GH and IGF-1 are believed to be physiological regulators of skeletal muscle mitochondria. The objective of this study was to examine the relationship between GH/IGF-1 and skeletal muscle mitochondria in obese subjects with reduced GH secretion in more detail. Fifteen abdominally obese men with reduced GH secretion were treated for 12 weeks with recombinant human GH. Subjects underwent (31)P-magnetic resonance spectroscopy to assess phosphocreatine (PCr) recovery as an in vivo measure of skeletal muscle mitochondrial function and percutaneous muscle biopsies to assess mRNA expression of IGF-1 and mitochondrial-related genes at baseline and 12 weeks. At baseline, skeletal muscle IGF-1 mRNA expression was significantly associated with PCr recovery (r = 0.79; P = .01) and nuclear respiratory factor-1 (r = 0.87; P = .001), mitochondrial transcription factor A (r = 0.86; P = .001), peroxisome proliferator-activated receptor (PPAR)γ (r = 0.72; P = .02), and PPARα (r = 0.75; P = .01) mRNA expression, and trended to an association with PPARγ coactivator 1-α (r = 0.59; P = .07) mRNA expression. However, serum IGF-1 concentration was not associated with PCr recovery or any mitochondrial gene expression (all P > .10). Administration of recombinant human GH increased both serum IGF-1 (change, 218 ± 29 μg/L; P < .0001) and IGF-1 mRNA in muscle (fold change, 2.1 ± 0.3; P = .002). Increases in serum IGF-1 were associated with improvements in total body fat (r = -0.53; P = .04), trunk fat (r = -0.55; P = .03), and lean mass (r = 0.58; P = .02), but not with PCr recovery (P > .10). Conversely, increase in muscle IGF-1 mRNA was associated with improvements in PCr recovery (r = 0.74; P = .02), but not with body composition parameters (P > .10). These data demonstrate a novel association of skeletal muscle mitochondria with muscle IGF-1 mRNA expression, but independent of serum IGF-1 concentrations.

Relationship Between Serum IGF-1 and Skeletal Muscle IGF-1 mRNA Expression to Phosphocreatine Recovery After Exercise in Obese Men With Reduced GH

PubMed Central

Hamarneh, Sulaiman R.; Murphy, Caitlin A.; Shih, Cynthia W.; Frontera, Walter; Torriani, Martin; Irazoqui, Javier E.

2015-01-01

Context: GH and IGF-1 are believed to be physiological regulators of skeletal muscle mitochondria. Objective: The objective of this study was to examine the relationship between GH/IGF-1 and skeletal muscle mitochondria in obese subjects with reduced GH secretion in more detail. Design: Fifteen abdominally obese men with reduced GH secretion were treated for 12 weeks with recombinant human GH. Subjects underwent 31P-magnetic resonance spectroscopy to assess phosphocreatine (PCr) recovery as an in vivo measure of skeletal muscle mitochondrial function and percutaneous muscle biopsies to assess mRNA expression of IGF-1 and mitochondrial-related genes at baseline and 12 weeks. Results: At baseline, skeletal muscle IGF-1 mRNA expression was significantly associated with PCr recovery (r = 0.79; P = .01) and nuclear respiratory factor-1 (r = 0.87; P = .001), mitochondrial transcription factor A (r = 0.86; P = .001), peroxisome proliferator-activated receptor (PPAR)γ (r = 0.72; P = .02), and PPARα (r = 0.75; P = .01) mRNA expression, and trended to an association with PPARγ coactivator 1-α (r = 0.59; P = .07) mRNA expression. However, serum IGF-1 concentration was not associated with PCr recovery or any mitochondrial gene expression (all P > .10). Administration of recombinant human GH increased both serum IGF-1 (change, 218 ± 29 μg/L; P < .0001) and IGF-1 mRNA in muscle (fold change, 2.1 ± 0.3; P = .002). Increases in serum IGF-1 were associated with improvements in total body fat (r = −0.53; P = .04), trunk fat (r = −0.55; P = .03), and lean mass (r = 0.58; P = .02), but not with PCr recovery (P > .10). Conversely, increase in muscle IGF-1 mRNA was associated with improvements in PCr recovery (r = 0.74; P = .02), but not with body composition parameters (P > .10). Conclusion: These data demonstrate a novel association of skeletal muscle mitochondria with muscle IGF-1 mRNA expression, but independent of serum IGF-1 concentrations. PMID:25375982

Identification and resolution of artifacts in the interpretation of imprinted gene expression

PubMed Central

Proudhon, Charlotte

2010-01-01

Genomic imprinting refers to genes that are epigenetically programmed in the germline to express exclusively or preferentially one allele in a parent-of-origin manner. Expression-based genome-wide screening for the identification of imprinted genes has failed to uncover a significant number of new imprinted genes, probably because of the high tissue- and developmental-stage specificity of imprinted gene expression. A very large number of technical and biological artifacts can also lead to the erroneous evidence of imprinted gene expression. In this article, we focus on three common sources of potential confounding effects: (i) random monoallelic expression in monoclonal cell populations, (ii) genetically determined monoallelic expression and (iii) contamination or infiltration of embryonic tissues with maternal material. This last situation specifically applies to genes that occur as maternally expressed in the placenta. Beside the use of reciprocal crosses that are instrumental to confirm the parental specificity of expression, we provide additional methods for the detection and elimination of these situations that can be misinterpreted as cases of imprinted expression. PMID:20829207

Identification and resolution of artifacts in the interpretation of imprinted gene expression.

PubMed

Proudhon, Charlotte; Bourc'his, Déborah

2010-12-01

Genomic imprinting refers to genes that are epigenetically programmed in the germline to express exclusively or preferentially one allele in a parent-of-origin manner. Expression-based genome-wide screening for the identification of imprinted genes has failed to uncover a significant number of new imprinted genes, probably because of the high tissue- and developmental-stage specificity of imprinted gene expression. A very large number of technical and biological artifacts can also lead to the erroneous evidence of imprinted gene expression. In this article, we focus on three common sources of potential confounding effects: (i) random monoallelic expression in monoclonal cell populations, (ii) genetically determined monoallelic expression and (iii) contamination or infiltration of embryonic tissues with maternal material. This last situation specifically applies to genes that occur as maternally expressed in the placenta. Beside the use of reciprocal crosses that are instrumental to confirm the parental specificity of expression, we provide additional methods for the detection and elimination of these situations that can be misinterpreted as cases of imprinted expression.

Increased prenatal IGF2 expression due to the porcine intron3-G3072A mutation may be responsible for increased muscle mass.

PubMed

Clark, D L; Clark, D I; Beever, J E; Dilger, A C

2015-05-01

A SNP (IGF2 G3072A) within intron 3 of disrupts a binding site for the repressor zinc finger BED-type containing 6 (ZBED6), leading to increased carcass lean yields in pigs. However, the relative contributions of prenatal as opposed to postnatal increased IGF2 expression are unclear. As muscle fiber number is set at birth, prenatal and neonate skeletal muscle development is critical in determining mature growth potential. Therefore, the objectives of this study were to determine the contributions of hyperplasia and hypertrophy to increased muscle mass and to delineate the effect of the mutation on the expression of myogenic genes during prenatal and postnatal growth. Sows (IGF2 A/A) were bred to a single heterozygous (IGF2 A/G) boar. For fetal samples, sows were euthanized at 60 and 90 d of gestation (d60 and d90) to obtain fetuses. Male and female offspring were also euthanized at birth (0d), weaning (21d), and market weight of approximately 130 kg (176d). At each sampling time, the LM, psoas major (PM), and semitendinosus (ST) muscles were weighed. Samples of the LM were used to quantify the expression of IGF family members, myogenic regulatory factors (MRF), myosin heavy chain isoforms, and growth factors, myostatin, and . Liver samples were used to quantify and expression. At 176d, weights of LM, PM, and ST muscles were all increased approximately 8% to 14% (P < 0.01) in pigs with paternal A (A(Pat)) alleles compared with those with paternal G (G(Pat)) alleles. Additionally, total muscle fiber number in the ST at 176d tended to be greater (P = 0.10), whereas muscle fiber cross-sectional area tended to be reduced ( P= 0.08) in A(Pat) pigs compared with G(Pat) pigs. In addition to the expected 2.7- to 4.5-fold increase (P ≤ 0.02) in expression in the LM in A(Pat) compared with G(Pat) pigs at postnatal sampling times (21d and 176d), IGF2 expression was also increased (P ≤ 0.06) 1.4- to 1.5-fold at d90 of gestation and at birth. At d90, expression of myogenic

Maternal low protein diet and postnatal high fat diet increases adipose imprinted gene expression

USDA-ARS?s Scientific Manuscript database

Maternal and postnatal diet can alter Igf2 gene expression and DNA methylation. To test whether maternal low protein and postnatal high fat (HF) diet result in alteration in Igf2 expression and obesity, we fed obese-prone Sprague-Dawley rats 8% (LP) or 20% (NP) protein for 3 wk prior to breeding and...

GENOMIC IMPRINTING, DISRUPTED PLACENTAL EXPRESSION, AND SPECIATION

PubMed Central

Brekke, Thomas D.; Henry, Lindy A.; Good, Jeffrey M.

2016-01-01

The importance of regulatory incompatibilities to the early stages of speciation remains unclear. Hybrid mammals often show extreme parent-of-origin growth effects that are thought to be a consequence of disrupted genetic imprinting (parent-specific epigenetic gene silencing) during early development. Here we test the long-standing hypothesis that abnormal hybrid growth reflects disrupted gene expression due to loss of imprinting (LOI) in hybrid placentas, resulting in dosage imbalances between paternal growth factors and maternal growth repressors. We analyzed placental gene expression in reciprocal dwarf hamster hybrids that show extreme parent-of-origin growth effects relative to their parental species. In massively enlarged hybrid placentas, we observed both extensive transgressive expression of growth-related genes and bi-allelic expression of many genes that were paternally silenced in normal sized hybrids. However, the apparent widespread disruption of paternal silencing was coupled with reduced gene expression levels overall. These patterns are contrary to the predictions of the LOI model and indicate that hybrid misexpression of dosage sensitive genes is caused by other regulatory mechanisms in this system. Collectively, our results support a central role for disrupted gene expression and imprinting in the evolution of mammalian hybrid inviability, but call into question the generality of the widely invoked LOI model. PMID:27714796

DDC and COBL, flanking the imprinted GRB10 gene on 7p12, are biallelically expressed.

PubMed

Hitchins, Megan P; Bentley, Louise; Monk, David; Beechey, Colin; Peters, Jo; Kelsey, Gavin; Ishino, Fumitoshi; Preece, Michael A; Stanier, Philip; Moore, Gudrun E

2002-12-01

Maternal duplication of human 7p11.2-p13 has been associated with Silver-Russell syndrome (SRS) in two familial cases. GRB10 is the only imprinted gene identified within this region to date. GRB10 demonstrates an intricate tissue- and isoform-specific imprinting profile in humans, with paternal expression in fetal brain and maternal expression of one isoform in skeletal muscle. The mouse homolog is maternally transcribed. The GRB10 protein is a potent growth inhibitor and represents a candidate for SRS, which is characterized by pre- and postnatal growth retardation and a spectrum of additional dysmorphic features. Since imprinted genes tend to be grouped in clusters, we investigated the imprinting status of the dopa-decarboxylase gene (DDC) and the Cordon-bleu gene (COBL) which flank GRB10 within the 7p11.2-p13 SRS duplicated region. Although both genes were found to replicate asynchronously, suggestive of imprinting, SNP expression analyses showed that neither gene was imprinted in multiple human fetal tissues. The mouse homologues, Ddc and Cobl, which map to the homologous imprinted region on proximal Chr 11, were also biallelically expressed in mice with uniparental maternal or paternal inheritance of this region. With the intent of using mouse Grb10 as an imprinted control, biallelic expression was consistently observed in fetal, postnatal, and adult brain of these mice, in contrast to the maternal-specific transcription previously demonstrated in brain in inter-specific F1 progeny. This may be a further example of over-expression of maternally derived transcripts in inter-specific mouse crosses. GRB10 remains the only imprinted gene identified within 7p11.2-p13.

Expression of IGF-1, IL-27 and IL-35 Receptors in Adjuvant Induced Rheumatoid Arthritis Model.

PubMed

Abdi, Elham; Najafipour, Hamid; Joukar, Siyavash; Dabiri, Shahriar; Esmaeli-Mahani, Saeed; Abbasloo, Elham; Houshmandi, Nasrin; Afsharipour, Abbas

2018-03-01

IGF-1 and certain other cytokines have been shown to exert inflammatory/anti-inflammatory roles in chronic joint diseases. To assess the effect of IGF-1, IL-27 and IL-35, their interaction and their receptor expression in a rheumatoid arthritis model. Freund's adjuvant-induced chronic joint inflammation was operated on 160 male rats. Animals were divided into histopathology and receptor expression groups, each composed of 10 subgroups including; control, vehicle, IGF-1, IL-27, IL-35, their antagonists, IGF-1+IL-27 antagonist and IGF-1+IL-35 antagonist. After two weeks, vehicle or agonist/antagonists were injected into the joint space every other day until day 28 where joint histopathology was performed. The expression of IGF-1, IL-27 and IL-35 receptors were assessed by western blot analysis. IGF-1 did not show pro- or anti- inflammatory functions; endogenous IL-27 and IL-35, on the other hand, exerted inflammatory effects. IL-27 and IL-35 antagonists exerted the highest anti-inflammatory effects. The total inflammation scores were 0.55 ± 0.06, 4.63 ± 0.40, 3.63 ± 0.60, 2.50 ± 0.38 and 1.63 ± 0.40 regarding control, vehicle, IGF-1 Ant., IL-27 Ant. and IL-35 Ant., respectively. IGF-1 receptor expression was reduced in chronic joint inflammation and all three antagonists augmented the IGF-1 receptor expression. IL-27 and IL-35 receptors were up-regulated by chronic joint inflammation. Overall, the results demonstrated the pro-inflammatory role of endogenous IL-27 and IL-35 along with the over expression of their receptors in chronic joint inflammation. IL-27 and IL-35 antagonists exerted the most anti-inflammatory effects and increased IGF-1 receptor expression. These two antagonists may be potential agents for new treatment strategies in chronic joint inflammatory diseases.

Tumor suppressor BRCA1 is expressed in prostate cancer and controls IGF-I receptor (IGF-IR) gene transcription in an androgen receptor-dependent manner

PubMed Central

Schayek, Hagit; Haugk, Kathy; Sun, Shihua; True, Lawrence D.; Plymate, Stephen R.; Werner, Haim

2010-01-01

Purpose The insulin-like growth factor (IGF) system plays an important role in prostate cancer. The BRCA1 gene encodes a transcription factor with tumor suppressor activity. The involvement of BRCA1 in prostate cancer, however, has not yet been elucidated. The purpose of the present study was to examine the functional correlations between BRCA1 and the IGF system in prostate cancer. Experimental Design An immunohistochemical analysis of BRCA1 was performed on Tissue Microarrays comprising 203 primary prostate cancer specimens. In addition, BRCA1 levels were measured in prostate cancer xenografts and in cell lines representing early stages of the disease (P69 cells) and advanced stages (M12 cells). The ability of BRCA1 to regulate IGF-IR expression was studied by coexpression experiments using a BRCA1 expression vector along with an IGF-IR promoter-luciferase reporter. Results We found significantly elevated BRCA1 levels in prostate cancer in comparison to histologically normal prostate tissue (p < 0.001). In addition, an inverse correlation between BRCA1 and IGF-IR levels was observed in the AR-negative P69 and M12 prostate cancer-derived cell lines. Coexpression experiments in M12 cells revealed that BRCA1 was able to suppress IGF-IR promoter activity and endogenous IGF-IR levels. On the other hand, BRCA1 enhanced IGF-IR levels in LnCaP C4-2 cells expressing an endogenous AR. Conclusions We provide evidence that BRCA1 differentially regulates IGF-IR expression in AR positive and negative prostate cancer cells. The mechanism of action of BRCA1 involves modulation of IGF-IR gene transcription. In addition, immunohistochemical data is consistent with a potential survival role of BRCA1 in prostate cancer. PMID:19223505

The complex genetics of human insulin-like growth factor 2 are not reflected in public databases.

PubMed

Rotwein, Peter

2018-03-23

Recent advances in genetics present unique opportunities for enhancing knowledge about human physiology and disease susceptibility. Understanding this information at the individual gene level is challenging and requires extracting, collating, and interpreting data from a variety of public gene repositories. Here, I illustrate this challenge by analyzing the gene for human insulin-like growth factor 2 ( IGF2 ) through the lens of several databases. IGF2, a 67-amino acid secreted peptide, is essential for normal prenatal growth and is involved in other physiological and pathophysiological processes in humans. Surprisingly, none of the genetic databases accurately described or completely delineated human IGF2 gene structure or transcript expression, even though all relevant information could be found in the published literature. Although IGF2 shares multiple features with the mouse Igf2 gene, it has several unique properties, including transcription from five promoters. Both genes undergo parental imprinting, with IGF2 / Igf2 being expressed primarily from the paternal chromosome and the adjacent H19 gene from the maternal chromosome. Unlike mouse Igf2 , whose expression declines after birth, human IGF2 remains active throughout life. This characteristic has been attributed to a unique human gene promoter that escapes imprinting, but as shown here, it involves several different promoters with distinct tissue-specific expression patterns. Because new testable hypotheses could lead to critical insights into IGF2 actions in human physiology and disease, it is incumbent that our fundamental understanding is accurate. Similar challenges affecting knowledge of other human genes should promote attempts to critically evaluate, interpret, and correct human genetic data in publicly available databases. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

AKT-induced PKM2 phosphorylation signals for IGF-1-stimulated cancer cell growth

PubMed Central

Park, Young Soo; Kim, Dong Joon; Koo, Han; Jang, Se Hwan; You, Yeon-Mi; Cho, Jung Hee; Yang, Suk-Jin; Yu, Eun Sil; Jung, Yuri; Lee, Dong Chul; Kim, Jung-Ae; Park, Zee-Yong; Park, Kyung Chan; Yeom, Young Il

2016-01-01

Pyruvate kinase muscle type 2 (PKM2) exhibits post-translational modifications in response to various signals from the tumor microenvironment. Insulin-like growth factor 1 (IGF-1) is a crucial signal in the tumor microenvironment that promotes cell growth and survival in many human cancers. Herein, we report that AKT directly interacts with PKM2 and phosphorylates it at Ser-202, which is essential for the nuclear translocation of PKM2 protein under stimulation of IGF-1. In the nucleus, PKM2 binds to STAT5A and induces IGF-1-stimulated cyclin D1 expression, suggesting that PKM2 acts as an important factor inducing STAT5A activation under IGF-1 signaling. Concordantly, overexpression of STAT5A in cells deficient in PKM2 expression failed to restore IGF-induced growth, whereas reconstitution of PKM2 in PKM2 knockdown cells restored the IGF-induced growth capacity. Our findings suggest a novel role of PKM2 in promoting the growth of cancers with dysregulated IGF/phosphoinositide 3-kinase/AKT signaling. PMID:27340866

Negative energy balance in dairy cows is associated with specific changes in IGF-binding protein expression in the oviduct

PubMed Central

Fenwick, M A; Llewellyn, S; Fitzpatrick, R; Kenny, D A; Murphy, J J; Patton, J; Wathes, D C

2008-01-01

Negative energy balance (NEB) during early lactation in dairy cows leads to an altered metabolic state that has major effects on the production of IGF family members. Low IGF-I concentrations are associated with poor fertility and therefore we aimed to determine whether NEB exerts a direct effect on IGF expression in the postpartum oviduct. Multiparous Holstein cows were allocated to two treatments (each n=6) designed using differential feeding and milking regimes to produce either mild NEB (MNEB) or severe NEB (SNEB). Animals were slaughtered in week 2 of lactation when divergent metabolic profiles were evident. Oviducts were collected for RNA analysis by real-time RT-PCR and in situ hybridisation. Quantitative measures in oviduct gene expression were obtained for all members of the IGF family (IGF-I/II, IGF-binding proteins (IGFBP) 1–6 and receptors for IGF types 1 and 2), insulin A/B, GH, glucocorticoid and oestrogen α/β. Expression of IGFBP-2 and IGFBP-6 (both of which have a high affinity for IGF-II) was decreased in SNEB relative to MNEB (P<0.05). No other gene was altered by NEB, but IGF-II, IGFBP-3, IGFBP-5 and IGFBP-6 all showed differential expression in different regions of the oviduct. These results indicate that, in addition to low circulating IGF-I after calving, NEB may also influence IGF availability in the oviduct indirectly through changes in specific IGFBP expression. It is possible that the predicted increased signalling by IGF-II may perturb embryo development, contributing to the high rates of embryonic mortality in dairy cows. PMID:18159084

Impact of PTEN on the expression of insulin-like growth factors (IGFs) and IGF-binding proteins in human gastric adenocarcinoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yi, Ho-Keun; Kim, Sun-Young; Hwang, Pyoung-Han

2005-05-13

PTEN is a tumor suppressor gene that is frequently mutated or deleted in a variety of human cancers including human gastric cancer. PTEN functions primarily as a lipid phosphatase and plays a key role in the regulation of the PI3 kinase/Akt pathway, thereby modulating cell proliferation and cell survival. On the other hand, the IGF system plays an important role in cell proliferation and cell survival via the PI3 kinase/Akt and MAP kinase pathways in many cancer cells. To characterize the impact of PTEN on the IGF-IGFR-IGFBP axis in gastric cancer, we overexpressed PTEN using an adenovirus gene transfer systemmore » in human gastric adenocarcinoma cells, SNU-484 and SNU-663, which lack PTEN. Overexpression of PTEN inhibited serum-induced as well as IGF-I-induced cell proliferation as compared to control cells. PTEN overexpression resulted in a significant decrease in the expression of IGF-I, -II, and IGF-IR. Interestingly, amongst the six IGFBPs, only IGFBP-3 was upregulated by PTEN, whereas IGFBP-4 and -6 were reduced. The IGFBP-3 promoter activity assay and Western immunoblotting demonstrate that PTEN regulates IGFBP-3 at the transcriptional level. In addition, the PI3 kinase inhibitor, LY294002, upregulates IGFBP-3 expression but downregulates IGF-I and IGF-II, indicating that PTEN controls IGFBP-3 and IGFs by an Akt-dependent pathway. These findings suggest that PTEN may inhibit antiapoptotic IGF actions not only by blocking the IGF-IGFR-induced Akt activity, but also by regulating expression of components of the IGF system, in particular, upregulation of IGFBP-3, which is known to exert antiproliferative effects through IGF-dependent and IGF-independent mechanisms in cancer cells.« less

IGF1 regulates PKM2 function through Akt phosphorylation

PubMed Central

Salani, Barbara; Ravera, Silvia; Amaro, Adriana; Salis, Annalisa; Passalacqua, Mario; Millo, Enrico; Damonte, Gianluca; Marini, Cecilia; Pfeffer, Ulrich; Sambuceti, Gianmario; Cordera, Renzo; Maggi, Davide

2015-01-01

Pyruvate kinase M2 (PKM2) acts at the crossroad of growth and metabolism pathways in cells. PKM2 regulation by growth factors can redirect glycolytic intermediates into key biosynthetic pathway. Here we show that IGF1 can regulate glycolysis rate, stimulate PKM2 Ser/Thr phosphorylation and decrease cellular pyruvate kinase activity. Upon IGF1 treatment we found an increase of the dimeric form of PKM2 and the enrichment of PKM2 in the nucleus. This effect was associated to a reduction of pyruvate kinase enzymatic activity and was reversed using metformin, which decreases Akt phosphorylation. IGF1 induced an increased nuclear localization of PKM2 and STAT3, which correlated with an increased HIF1α, HK2, and GLUT1 expression and glucose entrapment. Metformin inhibited HK2, GLUT1, HIF-1α expression and glucose consumption. These findings suggest a role of IGFIR/Akt axis in regulating glycolysis by Ser/Thr PKM2 phosphorylation in cancer cells. PMID:25790097

Hepatocellular carcinomas of the albumin SV40 T-antigen transgenic rat display fetal-like re-expression of lgf2 and deregulation of H19.

PubMed

Czarny, Matthew J; Babcock, Karlee; Baus, Rebecca M; Manoharan, Herbert; Pitot, Henry C

2007-09-01

Previous studies in our laboratory have shown that one of the earliest events during hepatocarcinogenesis in the albumin SV40 T antigen (Alb SV40 T Ag) transgenic rat is the duplication of chromosome 1q3.7-4.3, a region which contains the imprinted and coordinately regulated genes Igf2 and H19. We have also shown that this duplication is associated with the biallelic expression of the normally monoallelically-expressed H19. These results, however, are seemingly at odds with studies in the mouse that have shown a conservation of fetal regulatory patterns of these two genes in hepatic neoplasms. We therefore aimed in this study to determine the allelic origin of Igf2 expression in hepatocellular carcinomas of the Alb SV40 T Ag transgenic rat. Sprague-Dawley Alb SV40 T Ag transgenic rats and Brown Norway rats were reciprocally mated and the expression of Igf2 in hepatocellular carcinomas of the resulting F(1) transgene-positive female rats was analyzed by Northern blotting and RT-PCR. We determined that Igf2 was expressed exclusively from the paternal allele, which prompted the study (by the same methods) of the allelic origin of H19 in the same hepatocellular carcinomas in order to determine if the two genes remained coordinately regulated. Our results demonstrate fetal-like re-expression of Igf2 and deregulation of H19 in singular hepatocellular carcinomas of the rat. These results imply that another regulatory mechanism other than the generally accepted ICR/CTCF mechanism may play a role in the control of Igf2 and H19 expression. (c) 2007 Wiley-Liss, Inc.

Differential neuronal vulnerability identifies IGF-2 as a protective factor in ALS

PubMed Central

Allodi, Ilary; Comley, Laura; Nichterwitz, Susanne; Nizzardo, Monica; Simone, Chiara; Benitez, Julio Aguila; Cao, Ming; Corti, Stefania; Hedlund, Eva

2016-01-01

The fatal disease amyotrophic lateral sclerosis (ALS) is characterized by the loss of somatic motor neurons leading to muscle wasting and paralysis. However, motor neurons in the oculomotor nucleus, controlling eye movement, are for unknown reasons spared. We found that insulin-like growth factor 2 (IGF-2) was maintained in oculomotor neurons in ALS and thus could play a role in oculomotor resistance in this disease. We also showed that IGF-1 receptor (IGF-1R), which mediates survival pathways upon IGF binding, was highly expressed in oculomotor neurons and on extraocular muscle endplate. The addition of IGF-2 induced Akt phosphorylation, glycogen synthase kinase-3β phosphorylation and β-catenin levels while protecting ALS patient motor neurons. IGF-2 also rescued motor neurons derived from spinal muscular atrophy (SMA) patients from degeneration. Finally, AAV9::IGF-2 delivery to muscles of SOD1G93A ALS mice extended life-span by 10%, while preserving motor neurons and inducing motor axon regeneration. Thus, our studies demonstrate that oculomotor-specific expression can be utilized to identify candidates that protect vulnerable motor neurons from degeneration. PMID:27180807

Activation of ERK1/2 and PI3K/Akt by IGF-1 on GAP-43 expression in DRG neurons with excitotoxicity induced by glutamate in vitro.

PubMed

Liu, Zhen; Cai, Heng; Zhang, Ping; Li, Hao; Liu, Huaxiang; Li, Zhenzhong

2012-03-01

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and plays an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons. Whether IGF-1 influences growth-associated protein 43 (GAP-43) expression and activates the extracellular signal-regulated protein kinase (ERK1/2) and the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways in DRG neurons with excitotoxicity induced by glutamate (Glu) remains unknown. In this study, embryonic 15-day-old rat DRG explants were cultured for 48 h and then exposed to IGF-1, Glu, Glu + IGF-1, Glu + IGF-1 + PD98059, Glu + IGF-1 + LY294002, Glu + IGF-1 + PD98059 + LY294002 for additional 12 h. The DRG explants were continuously exposed to growth media as control. The levels of GAP-43 mRNA were detected by real time-PCR analysis. The protein levels of GAP-43, phosphorylated ERK1/2, phosphorylated Akt, total ERK1/2, and total Akt were detected by Western blot assay. GAP-43 expression in situ was determined by immunofluorescent labeling. Apoptotic cell death was monitored by Hoechst 33342 staining. IGF-1 alone increased GAP-43 and its mRNA levels in the absence of Glu. The decreased GAP-43 and its mRNA levels caused by Glu could be partially reversed by the presence of IGF-1. IGF-1 rescued neuronal cell death caused by Glu. Neither the ERK1/2 inhibitor PD98059 nor the PI3K inhibitor LY294002 blocked the effect of IGF-1, but both inhibitors together were effective. To validate the impact of GAP-43 expression by IGF-1, GAP-43 induction was blocked by administration of dexamethasone (DEX). IGF-1 partially rescued the decrease of GAP-43 and its mRNA levels induced by DEX. DEX induced an increase of cell apoptosis. IGF-1 may play an important role in neuroprotective effects on DRG neurons through regulating GAP-43 expression with excitotoxicity induced by Glu and the process was involved in both ERK1/2 and PI3K/Akt signaling pathways.

Gene expression profile in cerebrum in the filial imprinting of domestic chicks (Gallus gallus domesticus).

PubMed

Yamaguchi, Shinji; Fujii-Taira, Ikuko; Katagiri, Sachiko; Izawa, Ei-Ichi; Fujimoto, Yasuyuki; Takeuchi, Hideaki; Takano, Tatsuya; Matsushima, Toshiya; Homma, Koichi J

2008-06-15

In newly hatched chicks, gene expression in the brain has previously been shown to be up-regulated following filial imprinting. By applying cDNA microarrays containing 13,007 expressed sequence tags, we examined the comprehensive gene expression profiling of the intermediate medial mesopallium in the chick cerebrum, which has been shown to play a key role in filial imprinting. We found 52 up-regulated genes and 6 down-regulated genes of at least 2.0-fold changes 3h after the training of filial imprinting, compared to the gene expression of the dark-reared chick brain. The up-regulated genes are known to be involved in a variety of pathways, including signal transduction, cytoskeletal organization, nuclear function, cell metabolism, RNA binding, endoplasmic reticulum or Golgi function, synaptic function, ion channel, and transporter. In contrast, fewer genes were down-regulated in the imprinting, coinciding with the previous data that the total RNA synthesis increased associated with filial imprinting. Our data suggests that the filial imprinting involves the modulation of multiple signaling pathways.

Expression of HGF and IGF-1 during regeneration of masseter muscle in mdx mice.

PubMed

Honda, Hidemitsu; Abe, Shinichi; Ishida, Ryo; Watanabe, Yutaka; Iwanuma, Osamu; Sakiyama, Koji; Ide, Yoshinobu

2010-07-01

This study investigated the expression of the growth factors HGF and IGF-1 during the process of muscle regeneration in mdx mice. HGF and IGF-1 are reportedly expressed during the regeneration of muscle tissue in vitro. However, few studies have focused on the role of HGF and IGF-1 during muscle regeneration in mdx mice, which lack expression of the dystrophin gene. In the present study, we examined the expression of HGF and IGF-1 in masseter muscle during muscle regeneration in mdx and B10 (control) mice using histological analysis, immunohistochemistry and Western blotting, as well as examining gene expression by RT-PCR, at 3, 4 and 9 weeks. Mdx mice showed localized HGF and IGF-1 positivity in the cytoplasm of regenerating muscle cells at 3 and 4 weeks, but hardly any reactivity was evident at 9 weeks. The control group was completely negative for IGF-1 at any of the examined time points. Western blotting showed stronger expression of HGF and IGF-1 in mdx mice than in B10 mice at 3 and 4 weeks, but at 9 weeks the expression was absent in both groups. Similar results were obtained using RT-PCR. These present results suggest that HGF and IGF-1 appear to play an important role during regeneration of the masseter muscle in mdx mice.

Culture of preimplantation mouse embryos affects fetal development and the expression of imprinted genes.

PubMed

Khosla, S; Dean, W; Brown, D; Reik, W; Feil, R

2001-03-01

Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene MEST: Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.

IGF-1 modulates gene expression of proteins involved in inflammation, cytoskeleton, and liver architecture.

PubMed

Lara-Diaz, V J; Castilla-Cortazar, I; Martín-Estal, I; García-Magariño, M; Aguirre, G A; Puche, J E; de la Garza, R G; Morales, L A; Muñoz, U

2017-05-01

Even though the liver synthesizes most of circulating IGF-1, it lacks its receptor under physiological conditions. However, according to previous studies, a damaged liver expresses the receptor. For this reason, herein, we examine hepatic histology and expression of genes encoding proteins of the cytoskeleton, extracellular matrix, and cell-cell molecules and inflammation-related proteins. A partial IGF-1 deficiency murine model was used to investigate IGF-1's effects on liver by comparing wild-type controls, heterozygous igf1 +/- , and heterozygous mice treated with IGF-1 for 10 days. Histology, microarray for mRNA gene expression, RT-qPCR, and lipid peroxidation were assessed. Microarray analyses revealed significant underexpression of igf1 in heterozygous mice compared to control mice, restoring normal liver expression after treatment, which then normalized its circulating levels. IGF-1 receptor mRNA was overexpressed in Hz mice liver, while treated mice displayed a similar expression to that of the controls. Heterozygous mice showed overexpression of several genes encoding proteins related to inflammatory and acute-phase proteins and underexpression or overexpression of genes which coded for extracellular matrix, cytoskeleton, and cell junction components. Histology revealed an altered hepatic architecture. In addition, liver oxidative damage was found increased in the heterozygous group. The mere IGF-1 partial deficiency is associated with relevant alterations of the hepatic architecture and expression of genes involved in cytoskeleton, hepatocyte polarity, cell junctions, and extracellular matrix proteins. Moreover, it induces hepatic expression of the IGF-1 receptor and elevated acute-phase and inflammation mediators, which all resulted in liver oxidative damage.

Silencing and transcriptional properties of the imprinted Airn ncRNA are independent of the endogenous promoter

PubMed Central

Stricker, Stefan H; Steenpass, Laura; Pauler, Florian M; Santoro, Federica; Latos, Paulina A; Huang, Ru; Koerner, Martha V; Sloane, Mathew A; Warczok, Katarzyna E; Barlow, Denise P

2008-01-01

The Airn macro ncRNA is the master regulator of imprinted expression in the Igf2r imprinted gene cluster where it silences three flanking genes in cis. Airn transcription shows unusual features normally viewed as promoter specific, such as impaired post-transcriptional processing and a macro size. The Airn transcript is 108 kb long, predominantly unspliced and nuclear localized, with only a minority being variably spliced and exported. Here, we show by deletion of the Airn ncRNA promoter and replacement with a constitutive strong or weak promoter that splicing suppression and termination, as well as silencing activity, are maintained by strong Airn expression from an exogenous promoter. This indicates that all functional regions are located within the Airn transcript. DNA methylation of the maternal imprint control element (ICE) restricts Airn expression to the paternal allele and we also show that a strong active promoter is required to maintain the unmethylated state of the paternal ICE. Thus, Airn expression not only induces silencing of flanking mRNA genes but also protects the paternal copy of the ICE from de novo methylation. PMID:19008856

EXTRA-EMBRYONIC-SPECIFIC IMPRINTED EXPRESSION IS RESTRICTED TO DEFINED LINEAGES IN THE POST-IMPLANTATION EMBRYO

PubMed Central

Hudson, Quanah J.; Seidl, Christine I.M.; Kulinski, Tomasz M.; Huang, Ru; Warczok, Katarzyna E.; Bittner, Romana; Bartolomei, Marisa S.; Barlow, Denise P.

2011-01-01

A subset of imprinted genes in the mouse have been reported to show imprinted expression that is restricted to the placenta, a short-lived extra-embryonic organ. Notably these so-called 'placental-specific' imprinted genes are expressed from both parental alleles in embryo and adult tissues. The placenta is an embryonic-derived organ that is closely associated with maternal tissue and as a consequence, maternal contamination can be mistaken for maternal-specific imprinted expression. The complexity of the placenta, which arises from multiple embryonic lineages, poses additional problems in accurately assessing allele-specific repressive epigenetic modifications in genes that also show lineage-specific silencing in this organ. These problems require that extra evidence be obtained to support the imprinted status of genes whose imprinted expression is restricted to the placenta. We show here that the extra-embryonic visceral yolk sac (VYS), a nutritive membrane surrounding the developing embryo, shows a similar 'extra-embryonic-lineage-specific' pattern of imprinted expression. We present an improved enzymatic technique for separating the bilaminar VYS and show that this pattern of imprinted expression is restricted to the endoderm layer. Finally, we show that VYS 'extra-embryonic-lineage-specific' imprinted expression is regulated by DNA methylation in a similar manner as shown for genes showing multi-lineage imprinted expression in extra-embryonic, embryonic and adult tissues. These results show that the VYS is an improved model for studying the epigenetic mechanisms regulating extra-embryonic-lineage-specific imprinted expression. PMID:21354127

Pancreatic Fibroblasts Stimulate the Motility of Pancreatic Cancer Cells through IGF1/IGF1R Signaling under Hypoxia.

PubMed

Hirakawa, Toshiki; Yashiro, Masakazu; Doi, Yosuke; Kinoshita, Haruhito; Morisaki, Tamami; Fukuoka, Tatsunari; Hasegawa, Tsuyoshi; Kimura, Kenjiro; Amano, Ryosuke; Hirakawa, Kosei

2016-01-01

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its hypovascularity, with an extremely poor prognosis because of its highly invasive nature. PDAC proliferates with abundant stromal cells, suggesting that its invasive activity might be controlled by intercellular interactions between cancer cells and fibroblasts. Using four PDAC cell lines and two pancreas cancer-associated fibroblasts (CAFs), the expression of insulin-like growth factor-1 (IGF1) and IGF1 receptor (IGF1R) was evaluated by RT-PCR, FACScan, western blot, or ELISA. Correlation between IGF1R and the hypoxia marker carbonic anhydrase 9 (CA9) was examined by immunohistochemical staining of 120 pancreatic specimens. The effects of CAFs, IGF1, and IGF1R inhibitors on the motility of cancer cells were examined by wound-healing assay or invasion assay under normoxia (20% O2) and hypoxia (1% O2). IGF1R expression was significantly higher in RWP-1, MiaPaCa-2, and OCUP-AT cells than in Panc-1 cells. Hypoxia increased the expression level of IGF1R in RWP-1, MiaPaCa-2, and OCUP-AT cells. CA9 expression was correlated with IGF1R expression in pancreatic specimens. CAFs produced IGF1 under hypoxia, but PDAC cells did not. A conditioned medium from CAFs, which expressed αSMA, stimulated the migration and invasion ability of MiaPaCa-2, RWP-1, and OCUP-AT cells. The motility of all PDAC cells was greater under hypoxia than under normoxia. The motility-stimulating ability of CAFs was decreased by IGF1R inhibitors. These findings might suggest that pancreas CAFs stimulate the invasion activity of PDAC cells through paracrine IGF1/IGF1R signaling, especially under hypoxia. Therefore the targeting of IGF1R signaling might represent a promising therapeutic approach in IGF1R-dependent PDAC.

Sodium arsenite represses the expression of myogenin in C2C12 mouse myoblast cells through histone modifications and altered expression of Ezh2, Glp, and Igf-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Gia-Ming; Present address: The University of Chicago, Section of Hematology/Oncology, 900 E. 57th Street, Room 7134, Chicago, IL 60637; Bain, Lisa J., E-mail: lbain@clemson.edu

2012-05-01

Arsenic is a toxicant commonly found in water systems and chronic exposure can result in adverse developmental effects including increased neonatal death, stillbirths, and miscarriages, low birth weight, and altered locomotor activity. Previous studies indicate that 20 nM sodium arsenite exposure to C2C12 mouse myocyte cells delayed myoblast differentiation due to reduced myogenin expression, the transcription factor that differentiates myoblasts into myotubes. In this study, several mechanisms by which arsenic could alter myogenin expression were examined. Exposing differentiating C2C12 cells to 20 nM arsenic increased H3K9 dimethylation (H3K9me2) and H3K9 trimethylation (H3K9me3) by 3-fold near the transcription start site ofmore » myogenin, which is indicative of increased repressive marks, and reduced H3K9 acetylation (H3K9Ac) by 0.5-fold, indicative of reduced permissive marks. Protein expression of Glp or Ehmt1, a H3-K9 methyltransferase, was also increased by 1.6-fold in arsenic-exposed cells. In addition to the altered histone remodeling status on the myogenin promoter, protein and mRNA levels of Igf-1, a myogenic growth factor, were significantly repressed by arsenic exposure. Moreover, a 2-fold induction of Ezh2 expression, and an increased recruitment of Ezh2 (3.3-fold) and Dnmt3a (∼ 2-fold) to the myogenin promoter at the transcription start site (− 40 to + 42), were detected in the arsenic-treated cells. Together, we conclude that the repressed myogenin expression in arsenic-exposed C2C12 cells was likely due to a combination of reduced expression of Igf-1, enhanced nuclear expression and promoter recruitment of Ezh2, and altered histone remodeling status on myogenin promoter (− 40 to + 42). -- Highlights: ► Igf-1 expression is decreased in C2C12 cells after 20 nM arsenite exposure. ► Arsenic exposure alters histone remodeling on the myogenin promoter. ► Glp expression, a H3–K9 methyltransferase, was increased in arsenic-exposed cells

The effects of maternal anxiety during pregnancy on IGF2/H19 methylation in cord blood

PubMed Central

Mansell, T; Novakovic, B; Meyer, B; Rzehak, P; Vuillermin, P; Ponsonby, A-L; Collier, F; Burgner, D; Saffery, R; Ryan, J; Vuillermin, Peter; Ponsonby, Anne-Louise; Carlin, John B; Allen, Katie J; Tang, Mimi L; Saffery, Richard; Ranganathan, Sarath; Burgner, David; Dwyer, Terry; Jachno, Kim; Sly, Peter

2016-01-01

Compelling evidence suggests that maternal mental health in pregnancy can influence fetal development. The imprinted genes, insulin-like growth factor 2 (IGF2) and H19, are involved in fetal growth and each is regulated by DNA methylation. This study aimed to determine the association between maternal mental well-being during pregnancy and differentially methylated regions (DMRs) of IGF2 (DMR0) and the IGF2/H19 imprinting control region (ICR) in newborn offspring. Maternal depression, anxiety and perceived stress were assessed at 28 weeks of pregnancy in the Barwon Infant Study (n=576). DNA methylation was measured in purified cord blood mononuclear cells using the Sequenom MassArray Platform. Maternal anxiety was associated with a decrease in average ICR methylation (Δ=−2.23% 95% CI=−3.68 to −0.77%), and across all six of the individual CpG units in anxious compared with non-anxious groups. Birth weight and sex modified the association between prenatal anxiety and infant methylation. When stratified into lower (⩽3530 g) and higher (>3530 g) birth weight groups using the median birth weight, there was a stronger association between anxiety and ICR methylation in the lower birth weight group (Δ=−3.89% 95% CI=−6.06 to −1.72%), with no association in the higher birth weight group. When stratified by infant sex, there was a stronger association in female infants (Δ=−3.70% 95% CI=−5.90 to −1.51%) and no association in males. All the linear regression models were adjusted for maternal age, smoking and folate intake. These findings show that maternal anxiety in pregnancy is associated with decreased IGF2/H19 ICR DNA methylation in progeny at birth, particularly in female, low birth weight neonates. ICR methylation may help link poor maternal mental health and adverse birth outcomes, but further investigation is needed. PMID:27023171

Unbalancing p53/Mdm2/IGF-1R axis by Mdm2 activation restrains the IGF-1-dependent invasive phenotype of skin melanoma

PubMed Central

Worrall, C; Suleymanova, N; Crudden, C; Trocoli Drakensjö, I; Candrea, E; Nedelcu, D; Takahashi, S-I; Girnita, L; Girnita, A

2017-01-01

Melanoma tumors usually retain wild-type p53; however, its tumor-suppressor activity is functionally disabled, most commonly through an inactivating interaction with mouse double-minute 2 homolog (Mdm2), indicating p53 release from this complex as a potential therapeutic approach. P53 and the tumor-promoter insulin-like growth factor type 1 receptor (IGF-1R) compete as substrates for the E3 ubiquitin ligase Mdm2, making their relative abundance intricately linked. Hence we investigated the effects of pharmacological Mdm2 release from the Mdm2/p53 complex on the expression and function of the IGF-1R. Nutlin-3 treatment increased IGF-1R/Mdm2 association with enhanced IGF-1R ubiquitination and a dual functional outcome: receptor downregulation and selective downstream signaling activation confined to the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. This Nutlin-3 functional selectivity translated into IGF-1-mediated bioactivities with biphasic effects on the proliferative and metastatic phenotype: an early increase and late decrease in the number of proliferative and migratory cells, while the invasiveness was completely inhibited following Nutlin-3 treatment through an impaired IGF-1-mediated matrix metalloproteinases type 2 activation mechanism. Taken together, these experiments reveal the biased agonistic properties of Nutlin-3 for the mitogen-activated protein kinase pathway, mediated by Mdm2 through IGF-1R ubiquitination and provide fundamental insights into destabilizing p53/Mdm2/IGF-1R circuitry that could be developed for therapeutic gain. PMID:28092675

IGF-IEc expression is increased in secondary compared to primary foci in neuroendocrine neoplasms.

PubMed

Alexandraki, Krystallenia I; Philippou, Anastassios; Boutzios, Georgios; Theohari, Irini; Koutsilieris, Michael; Delladetsima, Ioanna Kassiani; Kaltsas, Gregory A

2017-10-03

Different Insulin-like growth factor-I (IGF-I) mRNA transcripts are produced by alternative splicing and particularly the IGF-IEc isoform has been implicated in the development and/or progression of various types of cancer. In the present study, we examined the potential role of IGF-IEc expression as a new immunohistochemical marker of aggressiveness in neuroendocrine neoplasms (NENs). We utilized immunohistochemical analysis in tissue specimens of 47 patients with NENs, to evaluate the expression of IGF-IEc (%) and Ki-67 proliferation index (%). Specimens from patients with tumors of different tissue origin, of either primary or metastatic lesions and of different grade were examined. Cytoplasmic IGF-IEc staining was found in 23 specimens of NENs or NECs: 10 pancreatic, 4 small bowel, 3 gastric, 1 lung, 1 uterine and 4 poorly differentiated of unknown primary origin. Ki-67 and IGF-IEc expression was positively correlated in all the samples studied (r=0.31, p=0.03). IGF-1Ec expression was more prevalent in specimens originating from metastatic foci with high Ki-67 compared to primary sites with low Ki-67 expression (p=0.036). These findings suggest a possible role of IGF-IEc in NEN tumorigenesis and progression to metastases that could be used as an additional new marker of a more aggressive behavior and a potential drugable target.

IGF-1 induces SOCS-2 but not SOCS-1 and SOCS-3 transcription in juvenile Nile tilapia (Oreochromis niloticus).

PubMed

Liu, Cai-Zhi; Luo, Yuan; Limbu, Samwel Mchele; Chen, Li-Qiao; Du, Zhen-Yu

2018-05-20

Insulin-like growth factor-1 (IGF-1) plays a crucial role in regulating growth in vertebrates whereas suppressors of cytokine signaling (SOCS) act as feedback inhibitors of the GH/IGF-1 axis. Although SOCS-2 binds the IGF-1 receptor and inhibits IGF-1-induced STAT3 activation, presently there is no clear evidence as to whether IGF-1 could induce SOCS gene expression. The current study aimed to determine whether IGF-1 could induce the transcription of SOCS in juvenile Nile tilapia ( Oreochromis niloticus ). We show that there is a common positive relationship between the mRNA expression of IGF-I and SOCS-2 under different nutritional statuses and stimulants, but not the mRNA expression of SOCS-1 and SOCS-3 Furthermore, rhIGF-1 treatment and transcriptional activity assay confirmed the hypothesis that IGF-1 could induce SOCS-2 expression, whereas it had no effect or even decreased the expression of SOCS-1 and SOCS-3 Overall, we obtained evidence that the transcription of SOCS-2, but not SOCS-1 or SOCS-3, could be induced by IGF signaling, suggesting that SOCS-2 serves as a feedback suppressor of the IGF-1 axis in juvenile Nile tilapia. © 2018. Published by The Company of Biologists Ltd.

Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy

PubMed Central

Li, Chao; Vu, Kent; Hazelgrove, Krystina

2015-01-01

The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. PMID:26428636

Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy.

PubMed

Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F

2015-12-01

The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. Copyright © 2015 the American Physiological Society.

GH/IGF-I Transgene Expression on Muscle Homeostasis

NASA Technical Reports Server (NTRS)

Schwartz, Robert J.

1999-01-01

We propose to test the hypothesis that the growth hormone/ insulin like growth factor-I axis through autocrine/paracrine mechanisms may provide long term muscle homeostasis under conditions of prolonged weightlessness. As a key alternative to hormone replacement therapy, ectopic production of hGH, growth hormone releasing hormone (GHRH), and IGF-I will be studied for its potential on muscle mass impact in transgenic mice under simulated microgravity. Expression of either hGH or IGF-I would provide a chronic source of a growth-promoting protein whose biosynthesis or secretion is shut down in space. Muscle expression of the IGF-I transgene has demonstrated about a 20% increase in hind limb muscle mass over control nontransgenic litter mates. These recent experiments, also establish the utility of hind-limb suspension in mice as a workable model to study atrophy in weight bearing muscles. Thus, transgenic mice will be used in hind-limb suspension models to determine the role of GH/IGF-I on maintenance of muscle mass and whether concentric exercises might act in synergy with hormone treatment. As a means to engineer and ensure long-term protein production that would be workable in humans, gene therapy technology will be used by to monitor muscle mass preservation during hind-limb suspension, after direct intramuscular injection of a genetically engineered muscle-specific vector expressing GHRH. Effects of this gene-based therapy will be assessed in both fast twitch (medial gastrocnemius) and slow twitch muscle (soleus). End-points include muscle size, ultrastructure, fiber type, and contractile function, in normal animals, hind limb suspension, and reambutation.

[Experimental study on dog's bone marrow stem cells transfected by pIRES2-EGFP-IGF-1 gene].

PubMed

Zhu, Guo-qiang; Wu, Zhi-fen; Li, Yuan-fei; Hu, De-hua; Wang, Qin-tao

2006-12-01

To establish the bone marrow stem cells (MSC) model which could highly express the insulin-like growth factor 1 (IGF-1) transfected by dog's IGF-1 gene. pIRES2-EGFP-IGF-1 was transfected into MSC by lipofectamine. Positive clones were selected with G418. The expression of IGF-1 protein in the MSC was determined by immunohistochemistry and Western blot analysis. The IGF-1 in the supernatant of the transfected MSC was detected by sandwich-in ELISA. The periodontal ligament cells (PDLC) were cultured in the supernatant of the transfected MSC. The changes of PDLC' proliferation were observed by MTT. IGF-1-transfected MSC could apparently express IGF-1. The IGF-1 protein in the supernatant of the transfected MSC was confirmed by sandwich-in ELISA. IGF-1 could promote the PDLC' proliferation. The MSC transfected by dog's IGF-1 gene can highly express IGF-1, which may lay the foundation for further study on periodontal regeneration.

Administration of growth hormone and nandrolone decanoate alters mRNA expression of the GABAB receptor subunits as well as of the GH receptor, IGF-1, and IGF-2 in rat brain.

PubMed

Grönbladh, Alfhild; Johansson, Jenny; Nyberg, Fred; Hallberg, Mathias

2014-01-01

The illicit use of anabolic androgenic steroids (AAS), especially among young adults, is of major concern. Among AAS users it is common to combine the AAS nandrolone decanoate (ND), with intake of growth hormone (GH) and a connection between gonadal steroids and the GH system has been suggested. Both AAS and GH affect functions in the brain, for example those associated with the hypothalamus and pituitary, and several GH actions are mediated by growth factors such as insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 2 (IGF-2). The GABAergic system is implicated in actions induced by AAS and previous studies have provided evidence for a link between GH and GABAB receptors in the brain. Our aim was to examine the impact of AAS administration and a subsequent administration of GH, on the expression of GABAB receptors and important GH mediators in rat brain. The aim was to investigate the CNS effects of a high-dose ND, and to study if a low, but physiological relevant, dose of GH could reverse the ND-induced effects. In the present study, male rats were administered a high dose of ND every third day during three weeks, and subsequently the rats were given recombinant human GH (rhGH) during ten days. Quantitative PCR (qPCR) was used to analyze gene expression in hypothalamus, anterior pituitary, caudate putamen, nucleus accumbens, and amygdala. In the pituitary gland, the expression of GABAB receptor subunits was affected differently by the steroid treatment; the GABAB1 mRNA expression was decreased whereas a distinct elevation of the GABAB2 expression was found. Administration of ND also caused a decrease of GHR, IGF-1, and IGF-2 mRNA expression in the pituitary while the corresponding expression in the hypothalamus, caudate putamen, nucleus accumbens, and amygdala was unaffected. The rhGH administration did not alter the GABAB2 expression but increased the GABAB1 gene expression in the hypothalamus as compared to the AAS treated group. These results

Association of IGF-I and IGF-II with myofiber regeneration in vivo.

PubMed

Keller, H L; St Pierre Schneider, B; Eppihimer, L A; Cannon, J G

1999-03-01

This study examined expression of insulinlike growth factor (IGF) in the myofibers and nonmyofibrillar structures of murine soleus muscle following contraction-induced damage. Identifying the cellular sources of this myogenic growth factor could improve muscle rehabilitation strategies. Immunohistochemical analysis of muscle sections indicated that the number of myofibers expressing both IGF-I and IGF-II increased significantly at 4, 7, and 10 days following injury, compared with control. Muscle spindles and vascular tissue expressed only IGF-II, and staining intensity did not change following injury. The number of fibers expressing developmental myosin heavy chain increased significantly at 7 and 10 days postinjury, and these usually coexpressed IGF. No IGF-specific staining of interstitial/inflammatory cells was observed. Therefore, expression of IGF after mechanically induced fiber damage occurs exclusively within regenerating fibers without supplemental delivery of IGF to the tissue by inflammatory cells or changes in constitutive expression of IGF-II in vascular tissue.

A Loss-of-Function Splice Acceptor Variant in IGF2 Is Protective for Type 2 Diabetes.

PubMed

Mercader, Josep M; Liao, Rachel G; Bell, Avery D; Dymek, Zachary; Estrada, Karol; Tukiainen, Taru; Huerta-Chagoya, Alicia; Moreno-Macías, Hortensia; Jablonski, Kathleen A; Hanson, Robert L; Walford, Geoffrey A; Moran, Ignasi; Chen, Ling; Agarwala, Vineeta; Ordoñez-Sánchez, María Luisa; Rodríguez-Guillen, Rosario; Rodríguez-Torres, Maribel; Segura-Kato, Yayoi; García-Ortiz, Humberto; Centeno-Cruz, Federico; Barajas-Olmos, Francisco; Caulkins, Lizz; Puppala, Sobha; Fontanillas, Pierre; Williams, Amy L; Bonàs-Guarch, Sílvia; Hartl, Chris; Ripke, Stephan; Tooley, Katherine; Lane, Jacqueline; Zerrweck, Carlos; Martínez-Hernández, Angélica; Córdova, Emilio J; Mendoza-Caamal, Elvia; Contreras-Cubas, Cecilia; González-Villalpando, María E; Cruz-Bautista, Ivette; Muñoz-Hernández, Liliana; Gómez-Velasco, Donaji; Alvirde, Ulises; Henderson, Brian E; Wilkens, Lynne R; Le Marchand, Loic; Arellano-Campos, Olimpia; Riba, Laura; Harden, Maegan; Gabriel, Stacey; Abboud, Hanna E; Cortes, Maria L; Revilla-Monsalve, Cristina; Islas-Andrade, Sergio; Soberon, Xavier; Curran, Joanne E; Jenkinson, Christopher P; DeFronzo, Ralph A; Lehman, Donna M; Hanis, Craig L; Bell, Graeme I; Boehnke, Michael; Blangero, John; Duggirala, Ravindranath; Saxena, Richa; MacArthur, Daniel; Ferrer, Jorge; McCarroll, Steven A; Torrents, David; Knowler, William C; Baier, Leslie J; Burtt, Noel; González-Villalpando, Clicerio; Haiman, Christopher A; Aguilar-Salinas, Carlos A; Tusié-Luna, Teresa; Flannick, Jason; Jacobs, Suzanne B R; Orozco, Lorena; Altshuler, David; Florez, Jose C

2017-11-01

Type 2 diabetes (T2D) affects more than 415 million people worldwide, and its costs to the health care system continue to rise. To identify common or rare genetic variation with potential therapeutic implications for T2D, we analyzed and replicated genome-wide protein coding variation in a total of 8,227 individuals with T2D and 12,966 individuals without T2D of Latino descent. We identified a novel genetic variant in the IGF2 gene associated with ∼20% reduced risk for T2D. This variant, which has an allele frequency of 17% in the Mexican population but is rare in Europe, prevents splicing between IGF2 exons 1 and 2. We show in vitro and in human liver and adipose tissue that the variant is associated with a specific, allele-dosage-dependent reduction in the expression of IGF2 isoform 2. In individuals who do not carry the protective allele, expression of IGF2 isoform 2 in adipose is positively correlated with both incidence of T2D and increased plasma glycated hemoglobin in individuals without T2D, providing support that the protective effects are mediated by reductions in IGF2 isoform 2. Broad phenotypic examination of carriers of the protective variant revealed no association with other disease states or impaired reproductive health. These findings suggest that reducing IGF2 isoform 2 expression in relevant tissues has potential as a new therapeutic strategy for T2D, even beyond the Latin American population, with no major adverse effects on health or reproduction. © 2017 by the American Diabetes Association.

Efficient and sustained IGF-1 expression in the adipose tissue-derived stem cells mediated via a lentiviral vector.

PubMed

Chen, Ting; Huang, Dangsheng; Chen, Guanghui; Yang, Tingshu; Yi, Jun; Tian, Miao

2015-02-01

The adipose tissue-derived stem cells (ADSCs) represent a significant area of the cell therapy. Genetic modification of ADSCs may further improve their therapeutic potential. Here, we aimed to generate a lentiviral vector expressing insulin-like growth factor-I (IGF-1) and investigate the impact of IGF-1 transduction on the properties of cultured ADSCs. Isolated rat ADSCs were assessed by flow cytometric analysis. IGF-1 was cloned and inserted into the pLenO-DCE plasmid to acquire pLenO-DCE-IGF-1 plasmid. Lentivirus was enveloped with pRsv-REV, pMDlg-pRRE and pMD2G plasmids in 293T cells. The ADSCs were transfected with the vectors. And then IGF-1-induced anti-apoptosis was evaluated by annexin V-FITC. Besides, proliferation of cells was detected by MTT assay and EdU. Moreover, Akt phosphorylation was evaluated by Western blotting analysis. Stable expression of IGF-1 in ADSCs was confirmed. ADSCs were positive for CD90 and CD29, but negative for CD31, CD34 and CD45. The transduction of IGF-1 to the ADSCs caused a dramatic increase in P-Akt expression. Over-expression of IGF-1 in ADSCs could improve the paracine of IGF-1 in a time-dependent manner, but could not promote the proliferation of ADSCs. This study indicated that lentiviral vectors offered a promising mean of delivering IGF-1 to the ADSCs. Lentiviral-mediated over-expression of therapeutic IGF-1 gene in ADSCs could prolong the anti-apoptosis effect of IGF-1, which might be induced by the activation of the PI3K/Akt pathway. And our data would improve the efficacy of ADSC-based therapies.

IGF2R Genetic Variants, Circulating IGF2 Concentrations and Colon Cancer Risk in African Americans and Whites

PubMed Central

Hoyo, Cathrine; Murphy, Susan K.; Schildkraut, Joellen M.; Vidal, Adriana C.; Skaar, David; Millikan, Robert C.; Galanko, Joseph; Sandler, Robert S.; Jirtle, Randy; Keku, Temitope

2012-01-01

The Mannose 6 Phosphate/Insulin-like Growth Factor Receptor-2 (IGF2R) encodes a type-1 membrane protein that modulates availability of the potent mitogen, IGF2. We evaluated the associations between IGF2R non-synonymous genetic variants (c.5002G>A, Gly1619Arg(rs629849), and c.901C>G, Leu252Val(rs8191754)), circulating IGF2 levels, and colon cancer (CC) risk among African American and White participants enrolled in the North Carolina Colon Cancer Study (NCCCS). Generalized linear models were used to compare circulating levels of IGF2 among 298 African American and 518 White controls. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of IGF2R genetic variants and CC risk. Women homozygous for the IGF2R c.5002 G>A allele, had higher mean levels of circulating IGF2, 828 (SD=321) ng/ml compared to non-carriers, 595 (SD=217) ng/ml (p-value=0.01). This pattern was not apparent in individuals homozygous for the IGF2R c.901 C>G variant. Whites homozygous for the IGF2R c.901 C>G variant trended towards a higher risk of CC, OR=2.2 [95% CI(0.9–5.4)], whereas carrying the IGF2R c.5002 G>A variant was not associated with CC risk. Our findings support the hypothesis that being homozygous for the IGF2R c.5002 G>A modulates IGF2 circulating levels in a sex-specific manner, and while carrying the IGF2R c.901 C>G may increase cancer risk, the mechanism may not involve modulation of circulating IGF2. PMID:22377707

IGF2R genetic variants, circulating IGF2 concentrations and colon cancer risk in African Americans and Whites.

PubMed

Hoyo, Cathrine; Murphy, Susan K; Schildkraut, Joellen M; Vidal, Adriana C; Skaar, David; Millikan, Robert C; Galanko, Joseph; Sandler, Robert S; Jirtle, Randy; Keku, Temitope

2012-01-01

The Mannose 6 Phosphate/Insulin-like Growth Factor Receptor-2 (IGF2R) encodes a type-1 membrane protein that modulates availability of the potent mitogen, IGF2. We evaluated the associations between IGF2R non-synonymous genetic variants (c.5002G>A, Gly1619Arg(rs629849), and c.901C>G, Leu252Val(rs8191754)), circulating IGF2 levels, and colon cancer (CC) risk among African American and White participants enrolled in the North Carolina Colon Cancer Study (NCCCS). Generalized linear models were used to compare circulating levels of IGF2 among 298 African American and 518 White controls. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of IGF2R genetic variants and CC risk. Women homozygous for the IGF2R c.5002 G>A allele, had higher mean levels of circulating IGF2, 828 (SD=321) ng/ml compared to non-carriers, 595 (SD=217) ng/ml (p-value=0.01). This pattern was not apparent in individuals homozygous for the IGF2R c.901 C>G variant. Whites homozygous for the IGF2R c.901 C>G variant trended towards a higher risk of CC, OR=2.2 [95% CI(0.9-5.4)], whereas carrying the IGF2R c.5002 G>A variant was not associated with CC risk. Our findings support the hypothesis that being homozygous for the IGF2R c.5002 G>A modulates IGF2 circulating levels in a sex-specific manner, and while carrying the IGF2R c.901 C>G may increase cancer risk, the mechanism may not involve modulation of circulating IGF2.

IGF2BP3 modulates the interaction of invasion-associated transcripts with RISC

PubMed Central

Ennajdaoui, Hanane; Howard, Jonathan M.; Sterne-Weiler, Timothy; Jahanbani, Fereshteh; Coyne, Doyle J.; Uren, Philip J.; Dargyte, Marija; Katzman, Sol; Draper, Jolene M.; Wallace, Andrew; Cazarez, Oscar; Burns, Suzanne C.; Qiao, Mei; Hinck, Lindsay; Smith, Andrew D.; Toloue, Masoud M.; Blencowe, Benjamin J.; Penalva, Luiz O.F.; Sanford, Jeremy R.

2016-01-01

Summary Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) expression correlates with malignancy. But its role(s) in pathogenesis remain enigmatic. Here, we interrogated the IGF2BP3-RNA interaction network in pancreatic ductal adenocarcinoma (PDAC) cells. Using a combination of genome-wide approaches we identify 164 direct mRNA targets of IGF2BP3. These transcripts encode proteins enriched for functions such as cell migration, proliferation and adhesion. Loss of IGF2BP3 reduced PDAC cell invasiveness and remodeled focal adhesion junctions. Individual-nucleotide resolution crosslinking immunoprecipitation (iCLIP) revealed significant overlap of IGF2BP3 and miRNA binding sites. IGF2BP3 promotes association of the RNA induced silencing complex (RISC) with specific transcripts. Our results show that IGF2BP3 influences a malignancy-associated RNA regulon by modulating miRNA-mRNA interactions. PMID:27210763

Increased cardiogenesis in P19-GFP teratocarcinoma cells expressing the propeptide IGF-1Ea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poudel, Bhawana; Bilbao, Daniel; Sarathchandra, Padmini

2011-12-16

Highlights: Black-Right-Pointing-Pointer In this study, we explored the function of IGF-1Ea propeptide in inducing cardiogenesis of stem cells. Black-Right-Pointing-Pointer IGF-1Ea promoted cardiac mesodermal induction in uncommitted cells. Black-Right-Pointing-Pointer Under differentiation condition, IGF-1Ea increased expression of cardiac differentiation markers. Black-Right-Pointing-Pointer Furthermore, it promoted formation of finely organized sarcomeric structure. Black-Right-Pointing-Pointer IGF-1Ea propeptide may be a good candidate to improve production of cardiomyocytes from pluripotent cells. -- Abstract: The mechanism implicated in differentiation of endogenous cardiac stem cells into cardiomyocytes to regenerate the heart tissue upon an insult remains elusive, limiting the therapeutical goals to exogenous cell injection and/or gene therapy. Wemore » have shown previously that cardiac specific overexpression of the insulin-like growth factor 1 propeptide IGF-1Ea induces beneficial myocardial repair after infarct. Although the mechanism is still under investigation, the possibility that this propeptide may be involved in promoting stem cell differentiation into the cardiac lineage has yet to be explored. To investigate whether IGF-1Ea promote cardiogenesis, we initially modified P19 embryonal carcinoma cells to express IGF-1Ea. Taking advantage of their cardiomyogenic nature, we analyzed whether overexpression of this propeptide affected cardiac differentiation program. The data herein presented showed for the first time that constitutively overexpressed IGF-1Ea increased cardiogenic differentiation program in both undifferentiated and DMSO-differentiated cells. In details, IGF-1Ea overexpression promoted localization of alpha-actinin in finely organized sarcomeric structure compared to control cells and upregulated the cardiac mesodermal marker NKX-2.5 and the ventricular structural protein MLC2v. Furthermore, activated IGF-1 signaling promoted cardiac

Maternal nutrient restriction in mid-to-late gestation influences fetal mRNA expression in muscle tissues in beef cattle.

PubMed

Paradis, Francois; Wood, Katie M; Swanson, Kendall C; Miller, Stephen P; McBride, Brian W; Fitzsimmons, Carolyn

2017-08-18

Manipulating maternal nutrition during specific periods of gestation can result in re-programming of fetal and post-natal development. In this experiment we investigated how a feed restriction of 85% compared with 140% of total metabolizable energy requirements, fed to cows during mid-to-late gestation, influences phenotypic development of fetuses and mRNA expression of growth (Insulin-Like Growth Factor family and Insulin Receptor (INSR)), myogenic (Myogenic Differentiation 1 (MYOD1), Myogenin (MYOG), Myocyte Enhancer Factor 2A (MEF2A), Serum Response Factor (SRF)) and adipogenic (Peroxisome Proliferator Activated Receptor Gamma (PPARG)) genes in fetal longissimus dorsi (LD) and semitendinosus (ST) muscle. DNA methylation of imprinted genes, Insulin Like Growth Factor 2 (IGF2) and Insulin Like Growth Factor 2 Receptor (IGF2R), and micro RNA (miRNA) expression, were also examined as potential consequences of poor maternal nutrition, but also potential regulators of altered gene expression patterns. While the nutrient restriction impacted dam body weight, no differences were observed in phenotypic fetal measurements (weight, crown-rump length, or thorax circumference). Interestingly, LD and ST muscles responded differently to the differential pre-natal nutrient levels. While LD muscle of restricted fetal calves had greater mRNA abundances for Insulin Like Growth Factor 1 and its receptor (IGF1 and IGF1R), IGF2R, INSR, MYOD1, MYOG, and PPARG, no significant differences were observed for gene expression in ST muscle. Similarly, feed restriction had a greater impact on the methylation level of IGF2 Differentially Methylated Region 2 (DMR2) in LD muscle as compared to ST muscle between treatment groups. A negative correlation existed between IGF2 mRNA expression and IGF2 DMR2 methylation level in both LD and ST muscles. Differential expression of miRNAs 1 and 133a were also detected in LD muscle. Our data suggests that a nutrient restriction of 85% as compared to 140

Exhaustive methylation analysis revealed uneven profiles of methylation at IGF2/ICR1/H19 11p15 loci in Russell Silver syndrome.

PubMed

Azzi, Salah; Steunou, Virginie; Tost, Jörg; Rossignol, Sylvie; Thibaud, Nathalie; Das Neves, Cristina; Le Jule, Marilyne; Habib, Walid Abi; Blaise, Annick; Koudou, Yves; Busato, Florence; Le Bouc, Yves; Netchine, Irène

2015-01-01

The structural organisation of the human IGF2/ICR1/H19 11p15 domain is very complex, and the mechanisms underlying its regulation are poorly understood. The Imprinted Center Region 1 (ICR1) contains seven binding sites for the zinc-finger protein CTCF (CBS: CTCF Binding Sites); three additional differentially methylated regions (DMR) are located at the H19 promoter (H19DMR) and two in the IGF2 gene (DMR0 and DMR2), respectively. Loss of imprinting at the IGF2/ICR1/H19 domain results in two growth disorders with opposite phenotypes: Beckwith-Wiedemann syndrome and Russell Silver syndrome (RSS). Despite the IGF2/ICR1/H19 locus being widely studied, the extent of hypomethylation across the domain remains not yet addressed in patients with RSS. We assessed a detailed investigation of the methylation status of the 11p15 ICR1 CBS1-7, IGF2DMR0 and H19DMR (H19 promoter) in a population of controls (n=50) and RSS carrying (n=104) or not (n=65) carrying a hypomethylation at the 11p15 ICR1 region. The methylation indexes (MI) were balanced at all regions in the control population and patients with RSS without any as yet identified molecular anomaly. Interestingly, patients with RSS with ICR1 hypomethylation showed uneven profiles of methylation among the CBSs and DMRs. Furthermore, normal MIs at CBS1 and CBS7 were identified in 9% of patients. The hypomethylation does not spread equally throughout the IGF2/ICR1/H19 locus, and some loci could have normal MI, which may lead to underdiagnosis of patients with RSS with ICR1 hypomethylation. The uneven pattern of methylation suggests that some CBSs may play different roles in the tridimensional chromosomal looping regulation of this locus. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

IGF2BP3 Modulates the Interaction of Invasion-Associated Transcripts with RISC.

PubMed

Ennajdaoui, Hanane; Howard, Jonathan M; Sterne-Weiler, Timothy; Jahanbani, Fereshteh; Coyne, Doyle J; Uren, Philip J; Dargyte, Marija; Katzman, Sol; Draper, Jolene M; Wallace, Andrew; Cazarez, Oscar; Burns, Suzanne C; Qiao, Mei; Hinck, Lindsay; Smith, Andrew D; Toloue, Masoud M; Blencowe, Benjamin J; Penalva, Luiz O F; Sanford, Jeremy R

2016-05-31

Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) expression correlates with malignancy, but its role(s) in pathogenesis remains enigmatic. We interrogated the IGF2BP3-RNA interaction network in pancreatic ductal adenocarcinoma (PDAC) cells. Using a combination of genome-wide approaches, we have identified 164 direct mRNA targets of IGF2BP3. These transcripts encode proteins enriched for functions such as cell migration, proliferation, and adhesion. Loss of IGF2BP3 reduced PDAC cell invasiveness and remodeled focal adhesion junctions. Individual nucleotide resolution crosslinking immunoprecipitation (iCLIP) revealed significant overlap of IGF2BP3 and microRNA (miRNA) binding sites. IGF2BP3 promotes association of the RNA-induced silencing complex (RISC) with specific transcripts. Our results show that IGF2BP3 influences a malignancy-associated RNA regulon by modulating miRNA-mRNA interactions. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Expression pattern of RAGE and IGF-1 in the human fetal ovary and ovarian serous carcinoma.

PubMed

Poljicanin, Ana; Filipovic, Natalija; Vukusic Pusic, Tanja; Soljic, Violeta; Caric, Ana; Saraga-Babic, Mirna; Vukojevic, Katarina

2015-01-01

The expression pattern of RAGE and IGF-1 proteins in different ovarian cell lineages was histologically analyzed in six fetal, nine adult human ovaries, and nine serous ovarian carcinomas (OSC) using immunohistochemical methods. Mild expression of IGF-1 in ovarian surface epithelium (Ose) and oocytes in the 15-week human ovaries increased to moderate or strong in the stromal cells, oocytes and follicular cells in week 22. Occasional mild RAGE expression was observed in Ose during week 15, while strong expression characterized primordial follicles in week 22. In the reproductive human ovary, IGF-1 was mildly to moderately expressed in all ovarian cell lineages except in theca cells of the tertiary follicle where IGF-1 was negative. RAGE was strongly positive in the granulosa cells and some theca cells of the tertiary follicle, while negative to mildly positive in all cells of the secondary follicle. In the postmenopausal human ovary IGF-1 and RAGE were mildly expressed in Ose and stroma. In OSC, cells were strongly positive to IGF-1 and RAGE, except for some negative stromal cells. Different levels of IGF-1 and RAGE co-expression characterized fetal ovarian cells during development. In reproductive ovaries, IGF-1 and RAGE were co-localized in the granulosa and theca interna cells of tertiary follicles, while in postmenopausal ovaries and OSC, IGF-1 and RAGE were co-localized in Ose and OSC cells respectively. Our results indicate that intracellular levels of IGF-1 and RAGE protein might regulate the final destiny of the ovarian cell populations prior and during folliculogenesis, possibly controlling the metastatic potential of OSC as well. Copyright © 2015. Published by Elsevier GmbH.

Disruption of insulin-like growth factor-II imprinting during embryonic development rescues the dwarf phenotype of mice null for pregnancy-associated plasma protein-A.

PubMed

Bale, Laurie K; Conover, Cheryl A

2005-08-01

Pregnancy-associated plasma protein-A (PAPP-A), an insulin-like growth factor-binding protein (IGFBP) protease, increases insulin-like growth factor (IGF) activity through cleavage of inhibitory IGFBP-4 and the consequent release of IGF peptide for receptor activation. Mice homozygous for targeted disruption of the PAPP-A gene are born as proportional dwarfs and exhibit retarded bone ossification during fetal development. Phenotype and in vitro data support a model in which decreased IGF-II bioavailability during embryogenesis results in growth retardation and reduction in overall body size. To test the hypothesis that an increase in IGF-II during embryogenesis would overcome the growth deficiencies, PAPP-A-null mice were crossed with DeltaH19 mutant mice, which have increased IGF-II expression and fetal overgrowth due to disruption of IgfII imprinting. DeltaH19 mutant mice were 126% and PAPP-A-null mice were 74% the size of controls at birth. These size differences were evident at embryonic day 16.5. Importantly, double mutants were indistinguishable from controls both in terms of size and skeletal development. Body size programmed during embryo development persisted post-natally. Thus, disruption of IgfII imprinting and consequent elevation in IGF-II during fetal development was associated with rescue of the dwarf phenotype and ossification defects of PAPP-A-null mice. These data provide strong genetic evidence that PAPP-A plays an essential role in determining IGF-II bioavailability for optimal fetal growth and development.

[Impact of acupuncture to IGF-I expression in spared dorsal root ganglion of cats].

PubMed

Liu, Fen; Wang, Ting-Hua; Zhang, Yi; Hong, Sun-quan; Song, Xin-bo

2006-05-01

To explore the relationship between Insulin-like growth factor-I (IGF-I) and acupuncture promoting the spinal cord plasticity, the changes of IGF- I expressing in spared dorsal root ganglia (DRG,L6) after operation and acupuncture were investigated. 25 adult cats were divided into 5 groups: normal control group; 7th day and 14th day group after unilateral partial rhizotomy (unilateral L1-L5,L7-S2 DRG Were transected, but L6 DRG was spared); 7th day and 14th day group of acupuncture stimulating the spared DRG (electro-needle stimulation was performed by following unilateral partial root rhizotomy). Animals survived for 7 or 14 days after operation respectively. Unilateral L6 dorsal root ganglia of each group were made into 20 microm frozen sections. By immunohistochemistry ABC method, the sections were stained with specific IGF-I (1:200) antibody. The distribution and the number of IGF-I positive neurons in spared DRG (L6) that located the operated/acupuncture side of each animal were observed and counted. For 7th day group after acupuncture stiumlation, the number of IGF-I positive neurons of spared DRG of acupuncture side showed significantly more than that of 7th day operation group (P<0.05), but still less than that of normal group (P < 0.05); In 14th day group, IGF- I expression in neuron of L6 DRG also increased apparently more than that of 14th day operation group, with coming back to normal level. After acupuncture stimulating the spared DRG for 14 days, the numbers of IGF- I positive neurons in spared DRG increased significantly more than that of 7th day group after acupuncture (P<0.05). Acupuncture can significantly increase the number of IGF- I positive neurons. Our results indicate that the expression changes of IGF-I in spared DRG associate with acupuncture promoting the spinal cord plasticity.

IGF-1 induces skeletal myocyte hypertrophy through calcineurin in association with GATA-2 and NF-ATc1

NASA Technical Reports Server (NTRS)

Musaro, A.; McCullagh, K. J.; Naya, F. J.; Olson, E. N.; Rosenthal, N.

1999-01-01

Localized synthesis of insulin-like growth factors (IGFs) has been broadly implicated in skeletal muscle growth, hypertrophy and regeneration. Virally delivered IGF-1 genes induce local skeletal muscle hypertrophy and attenuate age-related skeletal muscle atrophy, restoring and improving muscle mass and strength in mice. Here we show that the molecular pathways underlying the hypertrophic action of IGF-1 in skeletal muscle are similar to those responsible for cardiac hypertrophy. Transfected IGF-1 gene expression in postmitotic skeletal myocytes activates calcineurin-mediated calcium signalling by inducing calcineurin transcripts and nuclear localization of calcineurin protein. Expression of activated calcineurin mimics the effects of IGF-1, whereas expression of a dominant-negative calcineurin mutant or addition of cyclosporin, a calcineurin inhibitor, represses myocyte differentiation and hypertrophy. Either IGF-1 or activated calcineurin induces expression of the transcription factor GATA-2, which accumulates in a subset of myocyte nuclei, where it associates with calcineurin and a specific dephosphorylated isoform of the transcription factor NF-ATc1. Thus, IGF-1 induces calcineurin-mediated signalling and activation of GATA-2, a marker of skeletal muscle hypertrophy, which cooperates with selected NF-ATc isoforms to activate gene expression programs.

Association of tRNA methyltransferase NSUN2/IGF-II molecular signature with ovarian cancer survival.

PubMed

Yang, Jia-Cheng; Risch, Eric; Zhang, Meiqin; Huang, Chan; Huang, Huatian; Lu, Lingeng

2017-09-01

To investigate the association between NSUN2/IGF-II signature and ovarian cancer survival. Using a publicly accessible dataset of RNA sequencing and clinical follow-up data, we performed Classification and Regression Tree and survival analyses. Patients with NSUN2 high IGF-II low had significantly superior overall and disease progression-free survival, followed by NSUN2 low IGF-II low , NSUN2 high IGF-II high and NSUN2 low IGF-II high (p < 0.0001 for overall, p = 0.0024 for progression-free survival, respectively). The associations of NSUN2/IGF-II signature with the risks of death and relapse remained significant in multivariate Cox regression models. Random-effects meta-analyses show the upregulated NSUN2 and IGF-II expression in ovarian cancer versus normal tissues. The NSUN2/IGF-II signature associates with heterogeneous outcome and may have clinical implications in managing ovarian cancer.

The insulin-like growth factor 2 (IGF2) gene intron3-g.3072G>A polymorphism is not the only Sus scrofa chromosome 2p mutation affecting meat production and carcass traits in pigs: evidence from the effects of a cathepsin D (CTSD) gene polymorphism.

PubMed

Fontanesi, L; Speroni, C; Buttazzoni, L; Scotti, E; Dall'Olio, S; Nanni Costa, L; Davoli, R; Russo, V

2010-07-01

also confirmed in a subset of Italian Large White animals carrying the homozygous genotype IGF2 intron3-g.3072GG, and by haplotype analysis between the markers of the 2 considered genes in the complete data set. Overall, these results indicate that the IGF2 intron3-g.3072G>A mutation is not the only polymorphism affecting fatness and muscle deposition on SSC2p. Therefore, the CTSD g.70G>A polymorphism could be used to increase selection efficiency in marker-assisted selection programs that already use the IGF2 mutation. However, for practical applications, because the CTSD gene should not be imprinted (we obtained this information from expression analysis in adult skeletal muscle), the different modes of inheritance of the 2 genes have to be considered.

IGF2BP1 enhances an aggressive tumor cell phenotype by impairing miRNA-directed downregulation of oncogenic factors.

PubMed

Müller, Simon; Bley, Nadine; Glaß, Markus; Busch, Bianca; Rousseau, Vanessa; Misiak, Danny; Fuchs, Tommy; Lederer, Marcell; Hüttelmaier, Stefan

2018-04-12

The oncofetal IGF2 mRNA binding proteins (IGF2BPs) are upregulated in most cancers but their paralogue-specific roles in tumor cells remain poorly understood. In a panel of five cancer-derived cell lines, IGF2BP1 shows highly conserved oncogenic potential. Consistently, the deletion of IGF2BP1 impairs the growth and metastasis of ovarian cancer-derived cells in nude mice. Gene expression analyses in ovarian cancer-derived cells reveal that the knockdown of IGF2BPs is associated with the downregulation of mRNAs that are prone to miRNA regulation. All three IGF2BPs preferentially associate upstream of miRNA binding sites (MBSs) in the 3'UTR of mRNAs. The downregulation of mRNAs co-regulated by miRNAs and IGF2BP1 is abrogated at low miRNA abundance or when miRNAs are depleted. IGF2BP1 associates with these target mRNAs in RISC-free complexes and its deletion enhances their association with AGO2. The knockdown of most miRNA-regulated target mRNAs of IGF2BP1 impairs tumor cell properties. In four primary cancers, elevated synthesis of these target mRNAs is largely associated with upregulated IGF2BP1 mRNA levels. In ovarian cancer, the enhanced expression of IGF2BP1 and most of its miRNA-controlled target mRNAs is associated with poor prognosis. In conclusion, these findings indicate that IGF2BP1 enhances an aggressive tumor cell phenotype by antagonizing miRNA-impaired gene expression.

Maternal betaine supplementation in rats induces intergenerational changes in hepatic IGF-1 expression and DNA methylation.

PubMed

Zhao, Nannan; Yang, Shu; Hu, Yun; Dong, Haibo; Zhao, Ruqian

2017-08-01

Betaine is widely used in animal nutrition to promote growth. Here, we aimed to investigate whether maternal betaine supplementation during pregnancy can exert multigenerational effects on growth across two generations and the possible epigenetic modifications associated to such effects. In this study, 3-month-old female Sprague-Dawley rats were fed diet supplemented with 1% betaine throughout the pregnancy and lactation. Betaine-supplemented dams produced bigger litter but smaller F1 pups at birth and weaning. However, F2 pubs had higher weaning weight. In accordance with the growth performance, serum insulin-like growth factor 1 (IGF-1) levels were significantly lower in F1 yet higher in F2 pups, so was hepatic IGF-1 mRNA expression. Concurrently, dietary betaine supplementation to F0 dams increased hepatic expression of betaine homocysteine methyltransferase, at both mRNA and protein levels, in F1, but not F2 pups. Moreover, hepatic IGF-1 gene promoter 1 was detected to be significantly hypermethylated in F1 pups, whereas both promoters 1 and 2, together with almost all exons, were found to be hypomethylated in F2 offspring. Maternal betaine supplementation during pregnancy and lactation exerts distinct effects on growth of F1 and F2 rat offspring, probably through differential modification of IGF-1 gene methylation and expression in liver. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Munoz, Juan Pablo; Collao, Andres; Chiong, Mario

2009-10-09

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-inducedmore » MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal {alpha}-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.« less

Stress-altered synaptic plasticity and DAMP signaling in the hippocampus-PFC axis; elucidating the significance of IGF-1/IGF-1R/CaMKIIα expression in neural changes associated with a prolonged exposure therapy.

PubMed

Ogundele, Olalekan M; Ebenezer, Philip J; Lee, Charles C; Francis, Joseph

2017-06-14

Traumatic stress patients showed significant improvement in behavior after a prolonged exposure to an unrelated stimulus. This treatment method attempts to promote extinction of the fear memory associated with the initial traumatic experience. However, the subsequent prolonged exposure to such stimulus creates an additional layer of neural stress. Although the mechanism remains unclear, prolonged exposure therapy (PET) likely involves changes in synaptic plasticity, neurotransmitter function and inflammation; especially in parts of the brain concerned with the formation and retrieval of fear memory (Hippocampus and Prefrontal Cortex: PFC). Since certain synaptic proteins are also involved in danger-associated molecular pattern signaling (DAMP), we identified the significance of IGF-1/IGF-1R/CaMKIIα expression as a potential link between the concurrent progression of synaptic and inflammatory changes in stress. Thus, a comparison between IGF-1/IGF-1R/CaMKIIα, synaptic and DAMP proteins in stress and PET may highlight the significance of PET on synaptic morphology and neuronal inflammatory response. In behaviorally characterized Sprague-Dawley rats, there was a significant decline in neural IGF-1 (p<0.001), hippocampal (p<0.001) and cortical (p<0.05) IGF-1R expression. These animals showed a significant loss of presynaptic markers (synaptophysin; p<0.001), and changes in neurotransmitters (VGLUT2, Tyrosine hydroxylase, GABA, ChAT). Furthermore, naïve stressed rats recorded a significant decrease in post-synaptic marker (PSD-95; p<0.01) and synaptic regulator (CaMKIIα; p<0.001). As part of the synaptic response to a decrease in brain CaMKIIα, small ion conductance channel (KCa2.2) was upregulated in the brain of naïve stressed rats (p<0.01). After a PET, an increase in IGF-1 (p<0.05) and IGF-1R was recorded in the Stress-PET group (p<0.001). As such, hippocampal (p<0.001), but not cortical (ns) synaptophysin expression increased in Stress-PET. Although PSD-95

The interaction of IGF-1/IGF-1R and hydrogen sulfide on the proliferation of mouse primary vascular smooth muscle cells.

PubMed

Shuang, Tian; Fu, Ming; Yang, Guangdong; Wu, Lingyun; Wang, Rui

2018-03-01

Hydrogen sulfide (H 2 S) is mostly produced by cystathionine-gamma-lyase (CSE) in vascular system and it inhibits the proliferation of vascular smooth muscle cells (SMCs). Insulin-like growth factor-1 (IGF-1), via its receptor (IGF-1R), exerts multiple physiological and pathophysiological effects on the vasculature, including stimulating SMC proliferation and migration, and inhibiting SMC apoptosis. Since H 2 S and IGF-1/IGF-1R have opposite effects on SMC proliferation, it becomes imperative to better understand the interaction of these two signaling mechanisms on SMC proliferation. SMCs isolated from small mesenteric arteries of CSE knockout (KO) and wild-type (WT) mice were used in the present study. The effects of IGF-1 and H 2 S on SMC proliferation were evaluated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and bromodeoxyuridine (BrdU) assays. Protein expression was determined by western blot, and H 2 S-induced protein S-sulfhydration was assessed with a modified biotin switch assay. We found that IGF-1 dose-dependently increased the proliferation of both WT-SMCs and KO-SMCs, and this effect was more significant in KO-SMCs. Supplement of sodium hydrosulfide (NaHS) inhibited IGF-1-induced cell proliferation, while this effect was abolished by blocking IGF-1/IGF-1R signaling with picropodophyllin (PPP) or knocking out of the expression of IGF-1R. H 2 S significantly down-regulates the expression of IGF-1R, stimulates IGF-1R S-sulfhydration, and attenuates the binding of IGF-1 with IGF-1R. This study provides novel insight on the involvement of IGF-1/IGF-1R in H 2 S-inhibited SMC proliferation and suggests H 2 S-based innovative treatment strategies for proliferative cardiovascular diseases such as atherosclerosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Altered expression of IGF-I system in neurons of the inflamed spinal cord during acute experimental autoimmune encephalomyelitis.

PubMed

Parvaneh Tafreshi, Azita; Talebi, Farideh; Ghorbani, Samira; Bernard, Claude; Noorbakhsh, Farshid

2017-10-01

There is growing evidence that the impaired IGF-I system contributes to neurodegeneration. In this study, we examined the spinal cords of the EAE, the animal model of multiple sclerosis, to see if the expression of the IGF-I system is altered. To induce EAE, C57/BL6 mice were immunized with the Hooke lab MOG kit, sacrificed at the peak of the disease and their spinal cords were examined for the immunoreactivities (ir) of the IGF-I, IGF binding protein-1 (IGFBP-1) and glycogen synthase kinase 3β (GSK3β), as one major downstream molecule in the IGF-I signaling. Although neurons in the non EAE spinal cords did not show the IGF-I immunoreactivity, they were numerously positive for the IGFBP-1. In the inflamed EAE spinal cord however, the patterns of expressions were reversed, that is, a significant increased number of IGF-I expressing neurons versus a reduced number of IGFBP-1 positive neurons. Moreover, while nearly all IGF-I-ir neurons expressed GSK3β, some expressed it more intensely. Considering our previous finding where we showed a significant reduced number of the inactive (phosphorylated) but not that of the total GSK3β expressing neurons in the EAE spinal cord, it is conceivable that the intense total GSK3β expression in the IGF-I-ir neurons belongs to the active form of GSK3β known to exert neuroinflammatory effects. We therefore suggest that the altered expression of the IGF-I system including GSK3β in spinal cord neurons might involve in pathophysiological events during the EAE. © 2017 Wiley Periodicals, Inc.

Active and Repressive Chromatin Are Interspersed without Spreading in an Imprinted Gene Cluster in the Mammalian Genome

PubMed Central

Regha, Kakkad; Sloane, Mathew A.; Huang, Ru; Pauler, Florian M.; Warczok, Katarzyna E.; Melikant, Balázs; Radolf, Martin; Martens, Joost H.A.; Schotta, Gunnar; Jenuwein, Thomas; Barlow, Denise P.

2010-01-01

SUMMARY The Igf2r imprinted cluster is an epigenetic silencing model in which expression of a ncRNA silences multiple genes in cis. Here, we map a 250 kb region in mouse embryonic fibroblast cells to show that histone modifications associated with expressed and silent genes are mutually exclusive and localized to discrete regions. Expressed genes were modified at promoter regions by H3K4me3 + H3K4me2 + H3K9Ac and on putative regulatory elements flanking active promoters by H3K4me2 + H3K9Ac. Silent genes showed two types of nonoverlapping profile. One type spread over large domains of tissue-specific silent genes and contained H3K27me3 alone. A second type formed localized foci on silent imprinted gene promoters and a nonexpressed pseudogene and contained H3K9me3 + H4K20me3 ± HP1. Thus, mammalian chromosome arms contain active chromatin interspersed with repressive chromatin resembling the type of heterochromatin previously considered a feature of centromeres, telomeres, and the inactive X chromosome. PMID:17679087

Collagenase IV plays an important role in regulating hair cycle by inducing VEGF, IGF-1, and TGF-β expression

PubMed Central

Hou, Chun; Miao, Yong; Wang, Jin; Wang, Xue; Chen, Chao-Yue; Hu, Zhi-Qi

2015-01-01

Background It has been reported that collagenases (matrix metalloproteinase 2 [MMP-2] and matrix metalloproteinase 9 [MMP-9]) are associated with hair cycle, whereas the mechanism of the association is largely unknown. Methods The mice were randomly allocated into four groups: saline, and 5, 10, and 15 nM SB-3CT. Immunohistochemical analysis was employed to examine MMP-2 and MMP-9 protein. Real-time polymerase chain reaction and enzyme-linked immunosorbent assay were performed to determine mRNA and protein levels of VEGF, IGF-1, TGF-β, and GAPDH. Growing hair follicles from anagen phase III–IV were scored based on hematoxylin and eosin staining. Hair regrowth was also evaluated. Results Results showed that mRNA expressions of enzymes changed with a peak at late anagen and a trough at telogen after depilation. Immunostaining showed that the highest expression of MMP-2 was more than that of MMP-9, and the highest expression of enzymes changed during anagen. The localizations of MMP-2 changed from dermal papilla, keratinocyte strand, out of root sheath, and basal plate at early anagen, to hair bulb, inner root sheath, and outer root sheath at late anagen. The localization of MMP-9 changed from partial keratinocyte to dermal papilla at early anagen and to outer root sheath at late anagen. VEGF, IGF-1, and TGF-β have been shown to regulate hair growth. We found mRNA and protein expressions of VEGF and IGF-1 fluctuated with a peak at anagen and a decrease at catagen to telogen. In contrast, mRNA and protein expressions of TGF-β changed with highest and lowest levels at anagen and telogen, respectively. With selective inhibitor of collagenase IV, SB-3CT, mice showed significant suppressed hair growth and decreased expression of VEGF, IGF-1, and TGF-β. The MMPs agonist also significantly increased expression of VEGF, IGF-1, and TGF-β. Meanwhile, SB-3CT treatment significantly suppressed hair growth. Conclusion All these data suggest that the type IV collagenases

Loss of imprinting at the Dlk1-Gtl2 locus caused by insertional mutagenesis in the Gtl2 5' region

PubMed Central

Steshina, Ekaterina Y; Carr, Michael S; Glick, Elena A; Yevtodiyenko, Aleksey; Appelbe, Oliver K; Schmidt, Jennifer V

2006-01-01

Background The Dlk1 and Gtl2 genes define a region of mouse chromosome 12 that is subject to genomic imprinting, the parental allele-specific expression of a gene. Although imprinted genes play important roles in growth and development, the mechanisms by which imprinting is established and maintained are poorly understood. Differentially methylated regions (DMRs), which carry methylation on only one parental allele, are involved in imprinting control at many loci. The Dlk1-Gtl2 region contains three known DMRs, the Dlk1 DMR in the 3' region of Dlk1, the intergenic DMR 15 kb upstream of Gtl2, and the Gtl2 DMR at the Gtl2 promoter. Three mouse models are analyzed here that provide new information about the regulation of Dlk1-Gtl2 imprinting. Results A previously existing insertional mutation (Gtl2lacZ), and a targeted deletion in which the Gtl2 upstream region was replaced by a Neo cassette (Gtl2Δ5'Neo), display partial lethality and dwarfism upon paternal inheritance. Molecular characterization shows that both mutations cause loss of imprinting and changes in expression of the Dlk1, Gtl2 and Meg8/Rian genes. Dlk1 levels are decreased upon paternal inheritance of either mutation, suggesting Dlk1 may be causative for the lethality and dwarfism. Loss of imprinting on the paternal chromosome in both Gtl2lacZ and Gtl2Δ5'Neo mice is accompanied by the loss of paternal-specific Gtl2 DMR methylation, while maternal loss of imprinting suggests a previously unknown regulatory role for the maternal Gtl2 DMR. Unexpectedly, when the Neo gene is excised, Gtl2Δ5' animals are of normal size, imprinting is unchanged and the Gtl2 DMR is properly methylated. The exogenous DNA sequences integrated upstream of Gtl2 are therefore responsible for the growth and imprinting effects. Conclusion These data provide further evidence for the coregulation of the imprinted Dlk1 and Gtl2 genes, and support a role for Dlk1 as an important neonatal growth factor. The ability of the Gtl2lacZ and

Decoy Oligonucleotide Rescues IGF1R Expression from MicroRNA-223 Suppression

PubMed Central

Wang, Rong; He, Bao Mei; Qi, Bing; Xu, Chang Jun; Wu, Xing Zhong

2013-01-01

A mature miRNA generally suppresses hundreds of mRNA targets. To evaluate the selective effect of synthetic oligonucleotide decoys on hsa-miR-223 activity, reporters containing 3’ untranslated regions (UTR) of IGF1R, FOXO1, POLR3G, FOXO3, CDC27, FBXW7 and PAXIP1 mRNAs were constructed for the luciferase assay. The oligonucleotide decoys were designed and synthesized according to mature miR-223 sequence and its target mRNA sequence. Quantitative RT-PCR & western analysis were used to measure miR-223-targeted mRNA expression, Interestingly, apart from the antisense oligonucleotide, decoy nucleotides which were complementary to the 5’, central or 3’ region of mature miR-223 suppressed miR-223 targeting the 3’UTR of IGF1R, FOXO1, FOXO3, CDC27, POLR3G, and FBXW7 mRNAs and rescued the expression of these genes to varying degrees from miR-223 suppression at both mRNA and protein levels. All decoys had no effect on PAXIP1 which was not targeted by miR-223. The decoy 1 that was based on the sequence of IGF1R 3’UTR rescued the expression of IGF1R more significantly than other decoy nucleotides except the antisense decoy 4. Decoy 1 also rescued the expression of FOXO3 and POLR3G of which their 3’UTRs have similar binding sites for miR-223 with IGF1R 3’UTR. However decoy 1 failed to recover Sp1, CDC27 and FBXW7 expression. These data support that the sequence-specific decoy oligonucleotides might represent exogenous competing RNA which selectively inhibits microRNA targeting. PMID:24324762

Decoy oligonucleotide rescues IGF1R expression from MicroRNA-223 suppression.

PubMed

Wu, Li Hui; Cai, Qian Qian; Dong, Yi Wei; Wang, Rong; He, Bao Mei; Qi, Bing; Xu, Chang Jun; Wu, Xing Zhong

2013-01-01

A mature miRNA generally suppresses hundreds of mRNA targets. To evaluate the selective effect of synthetic oligonucleotide decoys on hsa-miR-223 activity, reporters containing 3' untranslated regions (UTR) of IGF1R, FOXO1, POLR3G, FOXO3, CDC27, FBXW7 and PAXIP1 mRNAs were constructed for the luciferase assay. The oligonucleotide decoys were designed and synthesized according to mature miR-223 sequence and its target mRNA sequence. Quantitative RT-PCR & western analysis were used to measure miR-223-targeted mRNA expression, Interestingly, apart from the antisense oligonucleotide, decoy nucleotides which were complementary to the 5', central or 3' region of mature miR-223 suppressed miR-223 targeting the 3'UTR of IGF1R, FOXO1, FOXO3, CDC27, POLR3G, and FBXW7 mRNAs and rescued the expression of these genes to varying degrees from miR-223 suppression at both mRNA and protein levels. All decoys had no effect on PAXIP1 which was not targeted by miR-223. The decoy 1 that was based on the sequence of IGF1R 3'UTR rescued the expression of IGF1R more significantly than other decoy nucleotides except the antisense decoy 4. Decoy 1 also rescued the expression of FOXO3 and POLR3G of which their 3'UTRs have similar binding sites for miR-223 with IGF1R 3'UTR. However decoy 1 failed to recover Sp1, CDC27 and FBXW7 expression. These data support that the sequence-specific decoy oligonucleotides might represent exogenous competing RNA which selectively inhibits microRNA targeting.

Insulin-like Growth Factor (IGF) Signaling Requires αvβ3-IGF1-IGF Type 1 Receptor (IGF1R) Ternary Complex Formation in Anchorage Independence, and the Complex Formation Does Not Require IGF1R and Src Activation

PubMed Central

Fujita, Masaaki; Takada, Yoko K.; Takada, Yoshikazu

2013-01-01

Integrin αvβ3 plays a role in insulin-like growth factor 1 (IGF1) signaling (integrin-IGF1 receptor (IGF1R) cross-talk) in non-transformed cells in anchorage-dependent conditions. We reported previously that IGF1 directly binds to αvβ3 and induces αvβ3-IGF1-IGF1R ternary complex formation in these conditions. The integrin-binding defective IGF1 mutant (R36E/R37E) is defective in inducing ternary complex formation and IGF signaling, whereas it still binds to IGF1R. We studied if IGF1 can induce signaling in anchorage-independent conditions in transformed Chinese hamster ovary cells that express αvβ3 (β3-CHO) cells. Here we describe that IGF1 signals were more clearly detectable in anchorage-independent conditions (polyHEMA-coated plates) than in anchorage-dependent conditions. This suggests that IGF signaling is masked by signals from cell-matrix interaction in anchorage-dependent conditions. IGF signaling required αvβ3 expression, and R36E/R37E was defective in inducing signals in polyHEMA-coated plates. These results suggest that αvβ3-IGF1 interaction, not αvβ3-extracellular matrix interaction, is essential for IGF signaling. Inhibitors of IGF1R, Src, AKT, and ERK1/2 did not suppress αvβ3-IGF-IGF1R ternary complex formation, suggesting that activation of these kinases are not required for ternary complex formation. Also, mutations of the β3 cytoplasmic tail (Y747F and Y759F) that block β3 tyrosine phosphorylation did not affect IGF1R phosphorylation or AKT activation. We propose a model in which IGF1 binding to IGF1R induces recruitment of integrin αvβ3 to the IGF-IGF1R complex and then β3 and IGF1R are phosphorylated. It is likely that αvβ3 should be together with the IGF1-IGF1R complex for triggering IGF signaling. PMID:23243309

Genetic characterisation of a cohort of children clinically labelled as GH or IGF1 insensitive: diagnostic value of serum IGF1 and height at presentation.

PubMed

Storr, Helen L; Dunkel, Leo; Kowalczyk, Julia; Savage, Martin O; Metherell, Louise A

2015-02-01

GH insensitivity (GHI) encompasses growth failure, low serum IGF1 and normal/elevated serum GH. By contrast, IGF1 insensitivity results in pre- and postnatal growth failure associated with relatively high IGF1 levels. From 2008 to 2013, 72 patients from 68 families (45M), mean age 7.1 years (0.4-17.0) with short stature (mean height SDS -3.9; range -9.4 to -1.5), were referred for sequencing. As a genetics referral centre, we have sequenced appropriate candidate genes (GHR, including its pseudoexon (6Ψ), STAT5B, IGFALS, IGF1, IGF1R, OBSL1, CUL7 and CCDC8) in subjects referred with suspected GHI (n=69) or IGF1 insensitivity (n=3). Mean serum IGF1 SDS was -2.7 (range -0.9 to -8.2) in GHI patients and 2.0, 3.7 and 4.4 in patients with suspected IGF1 insensitivity. Out of 69 GHI patients, 16 (23%) (19% families) had mutations in GH-IGF1 axis genes: homozygous GHR (n=13; 6 6Ψ, two novel IVS5ds+1 G to A) and homozygous IGFALS (n=3; one novel c.1291delT). In the GHI groups, two homozygous OBSL1 mutations were also identified (height SDS -4.9 and -5.7) and two patients had hypomethylation in imprinting control region 1 in 11p15 or mUPD7 consistent with Silver-Russell syndrome (SRS) (height SDS -3.7 and -4.3). A novel heterozygous IGF1R (c.112G>A) mutation was identified in one out of three (33%) IGF1-insensitive subjects. Genotyping contributed to the diagnosis of children with suspected GHI and IGF1 insensitivity, particularly in the GHI subjects with low serum IGF1 SDS (<-2.0) and height SDS (<-2.5). Diagnoses with similar phenotypes included SRS and 3-M syndrome. In 71% patients, no diagnosis was defined justifying further genetic investigation. © 2015 European Society of Endocrinology.

MMP-2 participates in the sclera of guinea pig with form-deprivation myopia via IGF-1/STAT3 pathway.

PubMed

Liu, Y-X; Sun, Y

2018-05-01

To investigate the expression changes of MMP-2 (matrix metalloproteinases-2) mediated by IGF-1 (insulin-like growth factors-1) STAT3 (signal transducer and activator of transcription 3) pathway in the sclera of the form-deprivation myopia guinea pigs. Twenty-four three-week-old guinea pigs were randomly divided into 4 groups: group A (Control), B, C and D. Guinea pigs in group A were sacrificed after 21 days without any special treatment. Guinea pigs in group B were sacrificed 7 days after receiving stitch in the right eye. Guinea pigs in group C were sacrificed 14 days after receiving stitch in the right eye. Guinea pigs in group D were sacrificed 21 days after receiving stitch in the right eye. Eyeball refraction and axial length of guinea pigs were measured before sacrifice. Eyeballs of guinea pigs were enucleated after sacrifice. The expressions of IGF-1, STAT3 and MMP-2 in scleral tissue were detected by Western blot. Axial length extension and myopia appeared in the right eye of guinea pigs in group B. The expressions of IGF-1, STAT3 and MMP-2 in the sclera significantly increased after 7 days of occlusion compared with that in control group A (p<0.05). In the right eye of group C, the axial prolongation and myopia formation appeared after 14-day occlusion. The expressions of IGF-1, STAT3 and MMP-2 in sclera significantly increased compared with that in group A (p<0.05). In the right eye of group D, the axial extension and myopia formation occurred. IGF-1, STAT3 and MMP-2 in scleral significantly upregulated 21 days after occlusion (p<0.05). Furthermore, at different stages of deprivation, protein expressions of MMP-2 and IGF-1 in sclera were positively correlated (r = 0.962, p<0.01). Form-deprivation of guinea pigs lead to increased expressions of IGF-1, STAT3 and MMP-2 in the sclera and myopia of guinea pigs. The expressions of IGF-1, STAT3 and MMP-2 increased progressively over the time of deprivation. Additionally, overexpression of MMP-2 mediated by IGF

IGF-1/IGF-1R/hsa-let-7c axis regulates the committed differentiation of stem cells from apical papilla

PubMed Central

Ma, Shu; Liu, Genxia; Jin, Lin; Pang, Xiyao; Wang, Yanqiu; Wang, Zilu; Yu, Yan; Yu, Jinhua

2016-01-01

Insulin-like growth factor-1 (IGF-1) and its receptor IGF-1R play a paramount role in tooth/bone formation while hsa-let-7c actively participates in the osteogenic differentiation of mesenchymal stem cells. However, the interaction between IGF-1/IGF-1R and hsa-let-7c on the committed differentiation of stem cells from apical papilla (SCAPs) remains unclear. In this study, human SCAPs were isolated and treated with IGF-1 and hsa-let-7c over/low-expression viruses. The odonto/osteogenic differentiation of these stem cells and the involvement of mitogen-activated protein kinase (MAPK) pathway were subsequently investigated. Alizarin red staining showed that hsa-let-7c low-expression can significantly promote the mineralization of IGF-1 treated SCAPs, while hsa-let-7c over-expression can decrease the calcium deposition of IGF-1 treated SCAPs. Western blot assay and real-time reverse transcription polymerase chain reaction further demonstrated that the expression of odonto/osteogenic markers (ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN, COL-I/COL-I, DSPP/DSP, and DMP-1/DMP-1) in IGF-1 treated SCAPs were significantly upregulated in Let-7c-low group. On the contrary, hsa-let-7c over-expression could downregulate the expression of these odonto/osteogenic markers. Moreover, western blot assay showed that the JNK and p38 MAPK signaling pathways were activated in Let-7c-low SCAPs but inhibited in Let-7c-over SCAPs. Together, the IGF-1/IGF-1R/hsa-let-7c axis can control the odonto/osteogenic differentiation of IGF-1-treated SCAPs via the regulation of JNK and p38 MAPK signaling pathways. PMID:27833148

MeCP2 deficiency in Rett syndrome causes epigenetic aberrations at the PWS/AS imprinting center that affects UBE3A expression.

PubMed

Makedonski, Kirill; Abuhatzira, Liron; Kaufman, Yotam; Razin, Aharon; Shemer, Ruth

2005-04-15

Rett syndrome (RS) is a severe and progressive neurodevelopmental disorder caused by heterozygous mutations in the X-linked methyl CpG binding protein 2 (MeCP2) gene. MeCP2 is a nuclear protein that binds specifically to methylated DNA and functions as a general transcription repressor in the context of chromatin remodeling complexes. RS shares clinical features with those of Angelman syndrome (AS), an imprinting neurodevelopmental disorder. In AS patients, the maternally expressed copy of UBE3A that codes for the ubiquitin protein ligase 3A (E6-AP) is repressed. The similar phenotype of these two syndromes led us to hypothesize that part of the RS phenotype is due to MeCP2-associated silencing of UBE3A. Indeed, UBE3A mRNA and protein are shown here to be significantly reduced in human and mouse MECP2 deficient brains. This reduced UBE3A level was associated with biallelic production of the UBE3A antisense RNA. In addition, MeCP2 deficiency resulted in elevated histone H3 acetylation and H3(K4) methylation and reduced H3(K9) methylation at the PWS/AS imprinting center, with no effect on DNA methylation or SNRPN expression. We conclude, therefore, that MeCP2 deficiency causes epigenetic aberrations at the PWS imprinting center. These changes in histone modifications result in loss of imprinting of the UBE3A antisense gene in the brain, increase in UBE3A antisense RNA level and, consequently reduction in UBE3A production.

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ping, E-mail: lping@sdu.edu.cn; Kong, Feng; Wang, Jue

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVACmore » proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS

Magnolol affects expression of IGF-1 and associated binding proteins in human prostate cancer cells in vitro.

PubMed

McKeown, Brendan T; Hurta, Robert A R

2014-11-01

This study investigated the effects of magnolol, a compound from Magnolia officinalis, on the behavior of LNCaP and PC3 human prostate cancer cells in vitro. In vitro cell culture approach with biochemical tests and Western blot analyses was used. Magnolol, (80 μM, 6 hour exposure) was found to affect the expression of insulin-like growth factor-1 (IGF-1) and associated proteins. In both cell lines, protein expression of IGF-1 and insulin-like growth factor binding protein-5 (IGFBP-5) were significantly decreased, while protein expression of IGFBP-3 was significantly increased. Additionally, protein expression of insulin-like growth factor-1 receptor (IGF-1R) was significantly increased and the phosphorylated form of IGF-1 (p-IGF-1R) was significantly decreased in PC3 cells, while IGFBP-4 protein expression was significantly increased in LNCaP cells. This study has demonstrated for the first time that magnolol can alter the expression of IGF-1 and associated proteins in human prostate cancer cells in vitro and suggests that magnolol may have a potential role as a novel anti-prostate cancer agent. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Intrauterine growth restriction and differential patterns of hepatic growth and expression of IGF1, PCK2, and HSDL1 mRNA in the sheep fetus in late gestation.

PubMed

Gentili, Sheridan; Morrison, Janna L; McMillen, I Caroline

2009-06-01

Fetal adaptations to periods of substrate deprivation can result in the programming of glucose intolerance, insulin resistance, and metabolic dysfunction in later life. Placental insufficiency can be associated with either sparing or sacrifice of fetal liver growth, and these different responses may have different metabolic consequences. It is unclear what intrahepatic mechanisms determine the differential responses of the fetal liver to substrate restriction. We investigated the effects of placental restriction (PR) on liver growth and the hepatic expression of SLC2A1, IGF1, IGF2, IGF1R, IGF2R, PPARGC1A, PPARA, PRKAA1, PRKAA2, PCK2, and HSDL1 mRNA in fetal sheep at 140-145 days of gestation. A mean gestational arterial partial pressure of oxygen less than 17 mmHg was defined as hypoxic, and a relative liver of weight more than 2 SD below the mean liver weight of controls was defined as reduced liver growth. Fetuses therefore were defined as control-normoxic (C-N; n = 9), PR-normoxic (PR-N; n = 7), PR-hypoxic (PR-H; n = 8), or PR-hypoxic reduced liver growth (PR-H RLG; n = 4). Hepatic SLC2A1 mRNA expression was highest (P < 0.05) in the PR-H fetuses, in which liver growth was maintained. Expression of IGF1 mRNA was decreased (P < 0.05) only in the PR-H RLG group. Hepatic expression of HSDL1, PPARGC1A, and PCK2 mRNA also were increased (P < 0.05) in the PR-H RLG fetuses. The present study highlights that intrahepatic responses to fetal substrate restriction may exist that protect the liver from decreased growth and, potentially, from a decreased responsiveness to the actions of insulin in postnatal life.

Mechanisms Underlying Testicular Damage and Dysfunction in Mice With Partial IGF-1 Deficiency and the Effectiveness of IGF-1 Replacement Therapy.

PubMed

Castilla-Cortázar, Inma; Gago, Alberto; Muñoz, Úrsula; Ávila-Gallego, Elena; Guerra-Menéndez, Lucía; Sádaba, María Cruz; García-Magariño, Mariano; Olleros Santos-Ruiz, María; Aguirre, G A; Puche, Juan Enrique

2015-12-01

To determine whether insulin-like growth factor (IGF-1) deficiency can cause testicular damage and to examine changes of the testicular morphology and testicular function-related gene expression caused by IGF-1 deficiency. Therefore, this study aims to determine the benefits of low doses of IGF-1 and to explore the mechanisms underlying the IGF-1 replacement therapy. A murine model of IGF-1 deficiency was used to avoid any factor that could contribute to testicular damage. Testicular weight, score of histopathological damage, and gene expressions were studied in 3 experimental groups of mice: controls (wild-type Igf1(+/+)), heterozygous Igf1(+/-) with partial IGF-1 deficiency, and heterozygous Igf1(+/-) treated with IGF-1. Results show that the partial IGF-1 deficiency induced testicular damage and altered expression of genes involved in IGF-1 and growth hormone signaling and regulation, testicular hormonal function, extracellular matrix establishment and its regulation, angiogenesis, fibrogenesis, inflammation, and cytoprotection. In addition, proteins involved in tight junction expression were found to be reduced. However, low doses of IGF-1 restored the testicular damage and most of these parameters. IGF-1 deficiency caused the damage of the blood-testis barrier and testicular structure and induced the abnormal testicular function-related gene expressions. However, low doses of IGF-1 constitute an effective replacement therapy that restores the described testicular damage. Data herein show that (1) cytoprotective activities of IGF-1 seem to be mediated by heat shock proteins and that (2) connective tissue growth factor could play a relevant role together with IGF-1 in the extracellular matrix establishment. Copyright © 2015 Elsevier Inc. All rights reserved.

Activation of IGF-2R stimulates cardiomyocyte hypertrophy in the late gestation sheep fetus

PubMed Central

Wang, Kimberley C W; Brooks, Doug A; Thornburg, Kent L; Morrison, Janna L

2012-01-01

In vitro studies using rat and fetal sheep cardiomyocytes indicate that, in addition to its role as a clearance receptor, the insulin-like growth factor 2 receptor (IGF-2R) can induce cardiomyocyte hypertrophy. In the present study, we have determined the effect of specific activation of the IGF-2R in the heart of the late gestation fetus on cardiomyocyte development. Leu27IGF-2, an IGF-2R agonist, was infused into the fetal left circumflex coronary artery for 4 days beginning at 128.1 ± 0.4 days gestation. Ewes were humanely killed at 132.2 ± 1.2 days gestation (term, 150 days). Fetuses were delivered and hearts dissected to isolate the cardiomyocytes and to collect and snap-freeze tissue. Leu27IGF-2 infusion into the left circumflex coronary artery of fetal sheep increased the area of binucleated cardiomyocytes in the left, but not the right, ventricle. However, this infusion of Leu27IGF-2 did not change fetal weight, heart weight, blood pressure, blood gases or cardiomyocyte proliferation/binucleation. The increase in cardiomyocyte size in the Leu27IGF-2-infused group was associated with increased expression of proteins in the Gαs, but not the Gαq, signalling pathway. We concluded that infusion of Leu27IGF-2 into the left circumflex coronary artery causes cardiac IGF-2R activation in the left ventricle of the heart, and this stimulates cardiomyocyte hypertrophy in a Gαs-dependent manner. PMID:22930271

Follicle-Stimulating Hormone Regulates igfbp Gene Expression Directly or via Downstream Effectors to Modulate Igf3 Effects on Zebrafish Spermatogenesis

PubMed Central

Safian, Diego; van der Kant, Henk J. G.; Crespo, Diego; Bogerd, Jan; Schulz, Rüdiger W.

2017-01-01

Previous work showed that pharmacological inactivation of Igf-binding proteins (Igfbps), modulators of Igf activity, resulted in an excessive differentiation of type A undifferentiated (Aund) spermatogonia in zebrafish testis in tissue culture when Fsh was present in the incubation medium. Using this testis tissue culture system, we studied here the regulation of igfbp transcript levels by Fsh and two of its downstream effectors, Igf3 and 11-ketotestosterone (11-KT). We also explored how Fsh-modulated igfbp expression affected spermatogonial proliferation by adding or removing the Igfbp inhibitor NBI-31772 at different times. Fsh (100 ng/mL) decreased the transcript levels of igfbp1a, -3, and -6a after 1 or 3 days, while increasing igfbp2a and -5b expression, but only after 5 days of incubation. Igf3 down-regulated the same igfbp transcripts as Fsh but with a delay of at least 4 days. 11-KT increased the transcripts (igfbp2a and 5b) that were elevated by Fsh and decreased those of igfbp6a, as did Fsh, while 11-KT did not change igfbp1a or -3 transcript levels. To evaluate Igfbps effects on spermatogenesis, we quantified under different conditions the mitotic indices and relative section areas occupied by the different spermatogonial generations (type Aund, type A differentiating (Adiff), or type B (B) spermatogonia). Igf3 (100 ng/mL) increased the area occupied by Adiff and B while decreasing the one for Aund. Interestingly, a concentration of Igf3 that was inactive by itself (25 ng/mL) became active in the presence of the Igfbp inhibitor NBI-31772 and mimicked the effect of 100 ng/mL Igf3 on spermatogonia. Studies exploiting the different dynamics of igfbp expression in response to Fsh and adding or removing NBI-31772 at different times showed that the quick downregulation of three igfbp as well as the delayed upregulated of two igfbps all support Igf3 bioactivity, namely the stimulation of spermatogonial differentiation. We conclude that Fsh

Imprinted expression in cystic embryoid bodies shows an embryonic and not an extra-embryonic pattern

PubMed Central

Kulinski, Tomasz M.; Casari, M. Rita T.; Guenzl, Philipp M.; Wenzel, Daniel; Andergassen, Daniel; Hladik, Anastasiya; Datlinger, Paul; Farlik, Matthias; Theussl, H. -Christian; Penninger, Josef M.; Knapp, Sylvia; Bock, Christoph; Barlow, Denise P.; Hudson, Quanah J.

2015-01-01

A large subset of mammalian imprinted genes show extra-embryonic lineage (EXEL) specific imprinted expression that is restricted to placental trophectoderm lineages and to visceral yolk sac endoderm (ysE). Isolated ysE provides a homogenous in vivo model of a mid-gestation extra-embryonic tissue to examine the mechanism of EXEL-specific imprinted gene silencing, but an in vitro model of ysE to facilitate more rapid and cost-effective experiments is not available. Reports indicate that ES cells differentiated into cystic embryoid bodies (EBs) contain ysE, so here we investigate if cystic EBs model ysE imprinted expression. The imprinted expression pattern of cystic EBs is shown to resemble fetal liver and not ysE. To investigate the reason for this we characterized the methylome and transcriptome of cystic EBs in comparison to fetal liver and ysE, by whole genome bisulphite sequencing and RNA-seq. Cystic EBs show a fetal liver pattern of global hypermethylation and low expression of repeats, while ysE shows global hypomethylation and high expression of IAPEz retroviral repeats, as reported for placenta. Transcriptome analysis confirmed that cystic EBs are more similar to fetal liver than ysE and express markers of early embryonic endoderm. Genome-wide analysis shows that ysE shares epigenetic and repeat expression features with placenta. Contrary to previous reports, we show that cystic EBs do not contain ysE, but are more similar to the embryonic endoderm of fetal liver. This explains why cystic EBs reproduce the imprinted expression seen in the embryo but not that seen in the ysE. PMID:25912690

Expression of IGF-I and Protein Degradation Markers During Hindlimb Unloading and Growth Hormone Administration in Rats

NASA Astrophysics Data System (ADS)

Leinsoo, T. A.; Turtikova, O. V.; Shenkman, B. S.

2013-02-01

It is known that hindlimb unloading or spaceflight produce atrophy and a number of phenotypic alterations in skeletal muscles. Many of these processes are triggered by the axis growth hormone/insulin-like growth factor I. However growth hormone (GH) and insulin-like growth factor I (IGF-I) expression relationship in rodent models of gravitational unloading is weakly investigated. We supposed the IGF-I is involved in regulation of protein turnover. In this study we examined the IGF-I expression by RT-PCR assay in the rat soleus, tibialis anterior and liver after 3 day of hindlimb suspension with growth hormone administration. Simultaneously were studied expression levels of MuRF-1 and MAFbx/atrogin as a key markers of intracellular proteolysis. We demonstrated that GH administration did not prevent IGF-I expression decreasing under the conditions of simulated weightlessness. It was concluded there are separate mechanisms of action of GH and IGF-I on protein metabolism in skeletal muscles. Gravitational unloading activate proteolysis independently of growth hormone activity.

Platycodon grandiflorum (PG) reverses angiotensin II-induced apoptosis by repressing IGF-IIR expression.

PubMed

Lin, Yuan-Chuan; Lin, Chih-Hsueh; Yao, Hsien-Tsung; Kuo, Wei-Wen; Shen, Chia-Yao; Yeh, Yu-Lan; Ho, Tsung-Jung; Padma, V Vijaya; Lin, Yu-Chen; Huang, Chih-Yang; Huang, Chih-Yang

2017-06-09

Platycodon grandiflorum (PG) is a Chinese medical plant used for decades as a traditional prescription to eliminate phlegm, relieve cough, reduce inflammation and lower blood pressure. PG also has a significant effect on the cardiovascular systems. The aqueous extract of Platycodon grandiflorum (JACQ.) A. DC. root was screened for inhibiting Ang II-induced IGF-IIR activation and apoptosis pathway in H9c2 cardiomyocytes. The effects were also studied in spontaneously hypertensive rats (five groups, n=5) using low and high doses of PG for 50 days. The Ang II-induced IGF-IIR activation was analyzed by luciferase reporter, RT-PCR, western blot and surface IGF-IIR expression assay. Furthermore, the major active constituent of PG was carried out by high performance liquid chromatography-mass spectrometry (HPLC-MS). Our results indicate that a crude extract of PG significantly suppresses the Ang II-induced IGF-IIR signaling pathway to prevent cardiomyocyte apoptosis. PG extract inhibits Ang II-mediated JNK activation and SIRT1 degradation to reduce IGF-IIR activity. Moreover, PG maintains SIRT1 stability to enhance HSF1-mediated IGF-IIR suppression, which prevents cardiomyocyte apoptosis. In animal models, the administration of PG markedly reduced this apoptotic pathway in the heart of SHRs. Taken together, PG may be considered as an effective treatment for cardiac diseases in hypertensive patients. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Serum from Chronic Hepatitis B Patients Promotes Growth and Proliferation via the IGF-II/IGF-IR/MEK/ERK Signaling Pathway in Hepatocellular Carcinoma Cells.

PubMed

Ji, Yuanyuan; Wang, Zhidong; Chen, Haiyan; Zhang, Lei; Zhuo, Fei; Yang, Qingqing

2018-05-09

Chronic hepatitis B virus (HBV) infection (CHB) plays a central role in the etiology of hepatocellular carcinoma (HCC). Emerging evidence implicates insulin-like growth factor (IGF)-II as a major risk factor for the growth and development of HCC. However, the relationship between HBV infection and IGF-II functions remains to be elucidated. Levels of circulating IGF-II and IGF-I receptor (IGF-IR) in healthy donors (HDs) and CHB patients were tested by ELISA. Human HCC cell lines (HepG-2, SMMC-7721, MHCC97-H) were incubated with serum from HDs and CHB patients at various concentrations for 24, 48, and 72 h. MTT and plate colony formation assays, BrdU ELISA, ELISA, small-interfering RNA (siRNA) transfection, quantitative real-time PCR, and western blot were applied to assess the functional and molecular mechanisms in HCC cell lines. Serum levels of IGF-II and IGF-IR were significantly higher in CHB patients than in HDs. Additionally, serum from CHB patients directly induced cell growth, proliferation, IGF-II secretion, and HDGF-related protein-2 (HRP-2) and nuclear protein 1 (NUPR1) mRNA and protein expression in HCC cells. Moreover, serum from CHB patients increased IGF-II-induced cell growth, proliferation, and HRP-2 and NUPR1 mRNA and protein expression in HCC cells. Blockade of IGF-IR clearly inhibited the above effects. Most importantly, interference with IGF-II function markedly repressed the cell proliferation and HRP-2 and NUPR1 mRNA and protein expression induced by serum from CHB patients. Furthermore, serum from CHB patients induced ERK phosphorylation via IGF-IR, with the MEK inhibitor PD98059 significantly decreasing CHB patient serum-induced IGF-II secretion, cell proliferation, and HRP-2 and NUPR1 mRNA and protein expression. Serum from CHB patients increases cell growth and proliferation and enhances HRP-2 and NUPR1 expression in HCC cells via the IGF-II/IGF-IR/MEK/ERK signaling pathway. These findings help to explain the molecular mechanisms

Oncogenic NRAS, Required for Pathogenesis of Embryonic Rhabdomyosarcoma, Relies upon the HMGA2–IGF2BP2 Pathway

PubMed Central

Li, Zhizhong; Zhang, Yunyu; Ramanujan, Krishnan; Ma, Yan; Kirsch, David G.; Glass, David J.

2013-01-01

Embryonic rhabdomyosarcoma (ERMS) is the most common soft-tissue tumor in children. Here, we report the identification of the minor groove DNA-binding factor high mobility group AT-hook 2 (HMGA2) as a driver of ERMS development. HMGA2 was highly expressed in normal myoblasts and ERMS cells, where its expression was essential to maintain cell proliferation, survival in vitro, and tumor outgrowth in vivo. Mechanistic investigations revealed that upregulation of the insulin–like growth factor (IGF) mRNA-binding protein IGF2BP2 was critical for HMGA2 action. In particular, IGF2BP2 was essential for mRNA and protein stability of NRAS, a frequently mutated gene in ERMS. shRNA-mediated attenuation of NRAS or pharmacologic inhibition of the MAP-ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) effector pathway showed that NRAS and NRAS-mediated signaling was required for tumor maintenance. Taken together, these findings implicate the HMGA2–IGFBP2–NRAS signaling pathway as a critical oncogenic driver in ERMS. PMID:23536553

An Unexpected Function of the Prader-Willi Syndrome Imprinting Center in Maternal Imprinting in Mice

PubMed Central

Wu, Mei-Yi; Jiang, Ming; Zhai, Xiaodong; Beaudet, Arthur L.; Wu, Ray-Chang

2012-01-01

Genomic imprinting is a phenomenon that some genes are expressed differentially according to the parent of origin. Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurobehavioral disorders caused by deficiency of imprinted gene expression from paternal and maternal chromosome 15q11–q13, respectively. Imprinted genes at the PWS/AS domain are regulated through a bipartite imprinting center, the PWS-IC and AS-IC. The PWS-IC activates paternal-specific gene expression and is responsible for the paternal imprint, whereas the AS-IC functions in the maternal imprint by allele-specific repression of the PWS-IC to prevent the paternal imprinting program. Although mouse chromosome 7C has a conserved PWS/AS imprinted domain, the mouse equivalent of the human AS-IC element has not yet been identified. Here, we suggest another dimension that the PWS-IC also functions in maternal imprinting by negatively regulating the paternally expressed imprinted genes in mice, in contrast to its known function as a positive regulator for paternal-specific gene expression. Using a mouse model carrying a 4.8-kb deletion at the PWS-IC, we demonstrated that maternal transmission of the PWS-IC deletion resulted in a maternal imprinting defect with activation of the paternally expressed imprinted genes and decreased expression of the maternally expressed imprinted gene on the maternal chromosome, accompanied by alteration of the maternal epigenotype toward a paternal state spread over the PWS/AS domain. The functional significance of this acquired paternal pattern of gene expression was demonstrated by the ability to complement PWS phenotypes by maternal inheritance of the PWS-IC deletion, which is in stark contrast to paternal inheritance of the PWS-IC deletion that resulted in the PWS phenotypes. Importantly, low levels of expression of the paternally expressed imprinted genes are sufficient to rescue postnatal lethality and growth retardation in two PWS mouse models. These findings

An unexpected function of the Prader-Willi syndrome imprinting center in maternal imprinting in mice.

PubMed

Wu, Mei-Yi; Jiang, Ming; Zhai, Xiaodong; Beaudet, Arthur L; Wu, Ray-Chang

2012-01-01

Genomic imprinting is a phenomenon that some genes are expressed differentially according to the parent of origin. Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurobehavioral disorders caused by deficiency of imprinted gene expression from paternal and maternal chromosome 15q11-q13, respectively. Imprinted genes at the PWS/AS domain are regulated through a bipartite imprinting center, the PWS-IC and AS-IC. The PWS-IC activates paternal-specific gene expression and is responsible for the paternal imprint, whereas the AS-IC functions in the maternal imprint by allele-specific repression of the PWS-IC to prevent the paternal imprinting program. Although mouse chromosome 7C has a conserved PWS/AS imprinted domain, the mouse equivalent of the human AS-IC element has not yet been identified. Here, we suggest another dimension that the PWS-IC also functions in maternal imprinting by negatively regulating the paternally expressed imprinted genes in mice, in contrast to its known function as a positive regulator for paternal-specific gene expression. Using a mouse model carrying a 4.8-kb deletion at the PWS-IC, we demonstrated that maternal transmission of the PWS-IC deletion resulted in a maternal imprinting defect with activation of the paternally expressed imprinted genes and decreased expression of the maternally expressed imprinted gene on the maternal chromosome, accompanied by alteration of the maternal epigenotype toward a paternal state spread over the PWS/AS domain. The functional significance of this acquired paternal pattern of gene expression was demonstrated by the ability to complement PWS phenotypes by maternal inheritance of the PWS-IC deletion, which is in stark contrast to paternal inheritance of the PWS-IC deletion that resulted in the PWS phenotypes. Importantly, low levels of expression of the paternally expressed imprinted genes are sufficient to rescue postnatal lethality and growth retardation in two PWS mouse models. These findings

Nuclear IGF-1R interacts with regulatory regions of chromatin to promote RNA polymerase II recruitment and gene expression associated with advanced tumor stage.

PubMed

Aleksic, Tamara; Gray, Nicki E; Wu, Xiaoning; Rieunier, Guillaume; Osher, Eliot; Mills, Jack; Verrill, Clare; Bryant, Richard J; Han, Cheng; Hutchinson, Kathryn; Lambert, Adam; Kumar, Rajeev; Hamdy, Freddie C; Weyer-Czernilofsky, Ulrike; Sanderson, Michael; Bogenrieder, Thomas; Taylor, Stephen; Macaulay, Valentine M

2018-05-07

Internalization of ligand-activated type 1 IGF receptor (IGF-1R) is followed by recycling to the plasma membrane, degradation or nuclear translocation. Nuclear IGF-1R reportedly associates with clinical response to IGF-1R inhibitory drugs, yet its role in the nucleus is poorly characterized. Here we investigated the significance of nuclear IGF-1R in clinical cancers and cell line models. In prostate cancers, IGF-1R was predominantly membrane-localized in benign glands, while malignant epithelium contained prominent internalized (nuclear/cytoplasmic) IGF-1R, and nuclear IGF-1R associated significantly with advanced tumor stage. Using ChIP-seq to assess global chromatin occupancy, we identified IGF-1R binding sites at or near transcription start sites of genes including JUN and FAM21, most sites coinciding with occupancy by RNA polymerase II (RNAPol2) and histone marks of active enhancers/promoters. IGF-1R was inducibly recruited to chromatin, directly binding DNA and interacting with RNAPol2 to upregulate expression of JUN and FAM21, shown to mediate tumor cell survival and IGF-induced migration. IGF-1 also enriched RNAPol2 on promoters containing IGF-1R binding sites. These functions were inhibited by IGF-1/2 neutralizing antibody xentuzumab (BI 836845), or by blocking receptor internalization. We detected nuclear IGF-1R on JUN and FAM21 promoters in fresh prostate cancers that contained abundant nuclear IGF-1R, with evidence of correlation between nuclear IGF-1R content and JUN expression in malignant prostatic epithelium. Taken together, these data reveal previously unrecognized molecular mechanisms through which IGFs promote tumorigenesis, with implications for therapeutic evaluation of anti-IGF drugs. Copyright ©2018, American Association for Cancer Research.

The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human renal cell carcinoma cell growth.

PubMed

Su, Ying; Zhao, An; Cheng, Guoping; Xu, Jingjing; Ji, Enming; Sun, Wenyong

2017-07-04

Renal cell carcinoma (RCC) is the highest mortality rate of the genitourinary cancers, and the treatment options are very limited. Thus, identification of molecular mechanisms underlying RCC tumorigenesis, is critical for identifying biomarkers for RCC diagnosis and prognosis. To validate whether the IGF-I/JAK2-STAT3/miR-21 signaling pathway is associated with human RCC cell growth. qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels, respectively. The MTT assay was performed to determine cell survival rate. The Annexin V-FITC/PI apoptosis detection kit was used to detect cell apoptosis. We employed RCC tissues and cell lines (A498; ACHN; Caki-1; Caki-2 and 786-O) in the study. IGF-I, and its inhibitor (NT-157) were administrated to detect the effects of IGF-I on the expression of miR-21 and p-JAK2. JAK2 inhibitor (AG490), and si-STAT3 were used to detect the effects of JAK2/STAT3 signaling pathway on the expression of miR-21. In our study, we firstly showed that the expression levels of IGF-I and miR-21 were up-regulated in RCC tissues and cell lines. After exogenous IGF-I treatment, the expression levels of miR-21, p-IGF-IR and p-JAK2 were significantly increased, whereas NT-157 treatment showed the reversed results. Further study indicated that JAK2 inhibitor or si-STAT3 significantly reversed the IGF-I-induced miR-21 expression level. Finally, we found that IGF-I treatment significantly prompted human RCC cell survival and inhibited cell apoptosis, and NT-157 treatment showed the reversed results. The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human RCC cell growth.

[Neurobiology of imprinting].

PubMed

Ohki-Hamazaki, Hiroko

2012-06-01

Imprinting is an example of learning and memory acquisition in infancy. In the case of precocial birds, such as geese, ducks, and chickens, the baby birds learn the characteristics of the first moving object that they see within a critical period, and they imprint on it and follow it around. We analyzed the neural basis of this behavior in order to understand the neural mechanism of learning and memory in infancy. Information pertaining to a visual imprinting stimulus is recognized and processed in the visual Wulst, a region that corresponds to the mammalian visual cortex. It is then transmitted to the posterior region of the telencephalon, followed by the core region of the hyperpallium densocellulare (HDCo), periventricular region of the hyperpallium densocellulare (HDPe), and finally, the intermediate medial mesopallium (IMM), a region similar to the mammalian association cortex. Memory is stored in the IMM. After imprint training, plastic changes are observed in the visual Wulst as well as in the neurons of this circuit. HDCo cells, located at the center of this circuit, express N-methyl-D-aspartate (NMDA) receptors containing the NMDA receptor (NR) 2B subunit; the expression of this receptor increased after the imprint training. Inhibition of this receptor in the cells of the HDCo region leads to failure of imprinting and inactivation of this circuit. Thus, NMDA receptors bearing the NR2B subunit play a critical role in plastic changes in this circuit and in induction of imprinting.

MicroRNA Let-7b inhibits keratinocyte migration in cutaneous wound healing by targeting IGF2BP2.

PubMed

Wu, Yan; Zhong, Julia Li; Hou, Ning; Sun, Yaolan; Ma, Benting; Nisar, Muhammad Farrukh; Teng, Yan; Tan, Zhaoli; Chen, Keping; Wang, Youliang; Yang, Xiao

2017-02-01

Wound healing is a complex process which involves proliferation and migration of keratinocyte for closure of epidermal injuries. A member of microRNA family, let-7b, has been expressed in mammalian skin, but its exact role in keratinocyte migration is still not in knowledge. Here, we showed that let-7b regulates keratinocyte migration by targeting the insulin-like growth factor IGF2BP2. Overexpression of let-7b led to reduced HaCaT cell migration, while knockdown of let-7b resulted in enhanced migration. Furthermore, let-7b was decreased during wound healing in wild-type mice, which led us to construct the transgenic mice with overexpression of let-7b in skin. The re-epithelialization of epidermis of let-7b transgenic mice was reduced during wound healing. Using bioinformatics prediction software and a reporter gene assay, we found that IGF2BP2 was a target of let-7b, which contributes to keratinocyte migration. Introduction of an expression vector of IGF2BP2 also rescued let-7b-induced migration deficiency, which confirms that IGF2BP2 is an important target for let-7b regulation. Our findings suggest that let-7b significantly delayed the re-epithelialization possibly due to reduction of keratinocyte migration and restraints IGF2BP2 during skin wound healing. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Impaired skeletal growth in mice with haploinsufficiency of IGF-I: genetic evidence that differences in IGF-I expression could contribute to peak bone mineral density differences

PubMed Central

Mohan, S; Baylink, D J

2010-01-01

Although it is well established that there is considerable inter-individual variation in the circulating levels of IGF-I in normal, healthy individuals and that a genetic component contributes substantially to this variation, the direct evidence that inter-individual variation in IGF-I contributes to differences in peak bone mineral density (BMD) is lacking. To examine if differences in IGF-I expression could contribute to peak BMD differences, we measured skeletal changes at days 23 (prepubertal), 31 (pubertal) and 56 (postpubertal) in mice with haploinsufficiency of IGF-I (+/−) and corresponding control mice (+/+). Mice (MF1/DBA) heterozygous for the IGF-I knockout allele were bred to generate +/+ and +/− mice (n=18–20 per group). Serum IGF-I was decreased by 23% (P<0·001) in mice with IGF-I haploinsufficiency (+/−) group at day 56 compared with the control (+/+) group. Femoral bone mineral content and BMD, as determined by dual energy X-ray absorptiometry, were reduced by 20% (P<0·001) and 12% respectively in the IGF-I (+/−) group at day 56 compared with the control group. The peripheral quantitative computed tomography measurements at the femoral mid-diaphysis revealed that periosteal circumference (7%, P<0·01) and total volumetric BMD (5%, P<0·05) were decreased significantly in the +/− group compared with the +/+ group. Furthermore, serum IGF-I showed significant positive correlations with both areal BMD (r=0·55) and periosteal circumference (r=0·66) in the pooled data from the +/+ and +/− groups. Our findings that haploinsufficiency of IGF-I caused significant reductions in serum IGF-I level, BMD and bone size, together with the previous findings, are consistent with the notion that genetic variations in IGF-I expression could, in part, contribute to inter-individual differences in peak BMD among a normal population. PMID:15930167

Structural analysis of the interaction of IGF I with the IGF types 1 and 2 and insulin receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cascieri, M.A.; Chicchi, G.G.; Hayes, N.S.

1987-05-01

A synthetic gene for human IGF I has been synthesized which directs the synthesis and secretion of fully active human IGF I (rIGF I) from yeast. rIGF I inhibits binding of /sup 125/I-IGF I to type 1 IGF receptors from human placenta (IGF-R1, IC50 = 4 nM), binding of /sup 125/I-insulin to insulin receptors (IR, IC50 = 881 nM), binding of /sup 125/I-MSA to type 2 IGF receptors from rat liver (IGF-R2, IC50 = 80 nM), and binding of /sup 125/I-IGF I to crude human serum binding protein (hBP, IC50 = 0.42 nM). rIGF I is equipotent to human IGFmore » I in stimulating glucose transport in murine BC3H1 cells and in stimulating DNA synthesis in rat A10 cells. Site directed mutagenesis of the synthetic gene is being used to characterize the structural requirements for binding to these receptors. IGF I (FFY) B(23-25) is equipotent to rIGF I at the IGF-R1 (6.9 nM), the IGF-R2 (36 nM), and the IR (841 nM) and is less potent at the hBP (1.7 nM). In contrast, IGF I(SFY) B(23-25) is 20-fold less potent than rIGF I at the IGF-R1 and is 10-fold less potent than rIGF I at hBP. This peptide is greater than 10-fold less active at the IGF-R2 and the IR. This peptide is a full agonist in the cell assays but 20-50 fold less potent than rIGF I. These data are consistent with the hypothesis that the F to S change destabilizes the tertiary structure of IGF I.« less

IGF-1 induces the epithelial-mesenchymal transition via Stat5 in hepatocellular carcinoma.

PubMed

Zhao, Chuanzong; Wang, Qian; Wang, Ben; Sun, Qi; He, Zhaobin; Hong, Jianguo; Kuehn, Florian; Liu, Enyu; Zhang, Zongli

2017-12-19

It has been reported that the epithelial-mesenchymal transition (EMT) plays an important role in hepatocellular carcinoma (HCC). However, the relationship between the insulin-like growth factor-1 (IGF-1) and EMT of HCC was not fully elucidated. In the present work, we found that the expression of N-cadherin, Vimentin, Snail1, Snail2, and Twist1 was positively associated with IGF-1R expression, while E-cadherin expression was negatively associated with IGF-1 expression in human HCC samples. Furthermore, we observed that IGF-1 up-regulated the expression of N-cadherin, Vimentin, Snail1, Snail2 and Twist1, and down-regulated the expression of E-cadherin. In addition, Stat5 was induced in IGF-1-treated HepG2 and Hep3B cells, and Stat5 inhibition or siRNA significantly affected IGF-1-induced EMT in HepG2 and Hep3B cells. In conclusion, IGF-1 induces EMT of HCC via Stat5 signaling pathway. Thus, IGF-1/Stat5 can be recommended as a potential and novel therapeutic strategy for HCC patients.

The oncogenic triangle of HMGA2, LIN28B and IGF2BP1 antagonizes tumor-suppressive actions of the let-7 family

PubMed Central

Busch, Bianca; Bley, Nadine; Müller, Simon; Glaß, Markus; Misiak, Danny; Lederer, Marcell; Vetter, Martina; Strauß, Hans-Georg; Thomssen, Christoph; Hüttelmaier, Stefan

2016-01-01

The tumor-suppressive let-7 microRNA family targets various oncogene-encoding mRNAs. We identify the let-7 targets HMGA2, LIN28B and IGF2BP1 to form a let-7 antagonizing self-promoting oncogenic triangle. Surprisingly, 3′-end processing of IGF2BP1 mRNAs is unaltered in aggressive cancers and tumor-derived cells although IGF2BP1 synthesis was proposed to escape let-7 attack by APA-dependent (alternative polyadenylation) 3′ UTR shortening. However, the expression of the triangle factors is inversely correlated with let-7 levels and promoted by LIN28B impairing let-7 biogenesis. Moreover, IGF2BP1 enhances the expression of all triangle factors by recruiting the respective mRNAs in mRNPs lacking AGO proteins and let-7 miRNAs. This indicates that the downregulation of let-7, largely facilitated by LIN28B upregulation, and the protection of let-7 target mRNAs by IGF2BP1-directed shielding in mRNPs synergize in enhancing the expression of triangle factors. The oncogenic potential of this triangle was confirmed in ovarian cancer (OC)-derived ES-2 cells transduced with let-7 targeting decoys. In these, the depletion of HMGA2 only diminishes tumor cell growth under permissive conditions. The depletion of LIN28B and more prominently IGF2BP1 severely impairs tumor cell viability, self-renewal and 2D as well as 3D migration. In conclusion, this suggests the targeting of the HMGA2-LIN28B-IGF2BP1 triangle as a promising strategy in cancer treatment. PMID:26917013

Deregulation of RB1 expression by loss of imprinting in human hepatocellular carcinoma.

PubMed

Anwar, Sumadi Lukman; Krech, Till; Hasemeier, Britta; Schipper, Elisa; Schweitzer, Nora; Vogel, Arndt; Kreipe, Hans; Lehmann, Ulrich

2014-08-01

The tumour suppressor gene RB1 is frequently silenced in many different types of human cancer, including hepatocellular carcinoma (HCC). However, mutations of the RB1 gene are relatively rare in HCC. A systematic screen for the identification of imprinted genes deregulated in human HCC revealed that RB1 shows imprint abnormalities in a high proportion of primary patient samples. Altogether, 40% of the HCC specimens (16/40) showed hyper- or hypomethylation at the CpG island in intron 2 of the RB1 gene. Re-analysis of publicly available genome-wide DNA methylation data confirmed these findings in two independent HCC cohorts. Loss of correct DNA methylation patterns at the RB1 locus leads to the aberrant expression of an alternative RB1-E2B transcript, as measured by quantitative real-time PCR. Demethylation at the intron 2 CpG island by DNMT1 knock-down or aza-deoxycytidine (DAC) treatment stimulated expression of the RB1-E2B transcript, accompanied by diminished RB1 main transcript expression. No aberrant DNA methylation was found at the RB1 locus in hepatocellular adenoma (HCA, n = 10), focal nodular hyperplasia (FNH, n = 5) and their corresponding adjacent liver tissue specimens. Deregulated RB1 expression due to hyper- or hypomethylation in intron 2 of the RB1 gene is found in tumours without loss of heterozygosity and is associated with a decrease in overall survival (p = 0.032) if caused by hypermethylation of CpG85. This unequivocally demonstrates that loss of imprinting represents an important additional mechanism for RB1 pathway inactivation in human HCC, complementing well-described molecular defects. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Analysis of expression patterns of IGF-1, caspase-3 and HSP-70 in developing human tooth germs.

PubMed

Kero, Darko; Kalibovic Govorko, Danijela; Medvedec Mikic, Ivana; Vukojevic, Katarina; Cigic, Livia; Saraga-Babic, Mirna

2015-10-01

To analyze expression patterns of IGF-1, caspase-3 and HSP-70 in human incisor and canine tooth germs during the late bud, cap and bell stages of odontogenesis. Head areas or parts of jaw containing teeth from 10 human fetuses aged between 9th and 20th developmental weeks were immunohistochemically analyzed using IGF-1, active caspase-3 and HSP-70 markers. Semi-quantitative analysis of each marker's expression pattern was also performed. During the analyzed period, IGF-1 and HSP-70 were mostly expressed in enamel organ. As development progressed, expression of IGF-1 and HSP-70 became more confined to differentiating tissues in the future cusp tip area, as well as in highly proliferating cervical loops. Few apoptotic bodies highly positive to active caspase-3 were observed in enamel organ and dental papilla from the cap stage onward. However, both enamel epithelia moderately expressed active caspase-3 throughout the investigated period. Expression patterns of IGF-1, active caspase-3 and HSP-70 imply importance of these factors for early human tooth development. IGF-1 and HSP-70 have versatile functions in control of proliferation, differentiation and anti-apoptotic protection of epithelial parts of human enamel organ. Active caspase-3 is partially involved in formation and apoptotic removal of primary enamel knot, although present findings might reflect its ability to perform other non-death functions such as differentiation of hard dental tissues secreting cells and guidance of ingrowth of proliferating cervical loops. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enforced epithelial expression of IGF-1 causes hyperplastic prostate growth while negative selection is requisite for spontaneous metastogenesis

USDA-ARS?s Scientific Manuscript database

The insulin-like growth factor-1 (IGF-1) signaling axis is important for cell growth, differentiation, and survival, and increased serum IGF is a risk factor for prostate and other cancers. To study IGF-1 action on the prostate, we created transgenic (PB-Des) mice that specifically express human IGF...

Impact of IGF-1, IGF-1R, and IGFBP-3 promoter methylation on the risk and prognosis of esophageal carcinoma.

PubMed

Ye, Peng; Qu, Chang-Fa; Hu, Xue-Lin

2016-05-01

The aim of this study is to investigate IGF-1, IGF-1R, and IGFBP-3 methylations in esophageal carcinoma (EC) patients and their relationship with the development and prognosis of EC. This study population consisted of 264 patients (case group) whom EC radical resection was performed and 283 healthy individuals (control group). Methylation-specific PCR (MSP) detected the methylation status of IGF-1, IGF-1R, and IGFBP-3 in the peripheral blood in both groups. The expressions of IGF-1, IGF-1R, and IGFBP-3 in EC and adjacent normal tissues were detected by immunohistochemistry (IHC). The methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 in the case group were higher than those in the control group (all P < 0.05). Additionally, there were statistical significances for the methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 IGF-1 among patients of different clinicopathological features (all P < 0.05). The positive expression rates of IGF-1 and IGF-1R in EC were significantly higher than those in adjacent normal tissues (both P < 0.001), and the rate of IGFBP-3 in EC was significantly lower than that in adjacent normal tissues (P < 0.05). Correlation analysis showed that IGF-1 and IGF1R gene promoter methylation was positively correlated with the positive expressions of IGF-1 (r = 0.139, P = 0.024) and IGF-1R (r = 0.135, P = 0.028), while the IGFBP3 methylation was negatively correlated with the positive expression of IGFBP3 (r = -0.133, P = 0.031). The positive expressions of IGF-1, IGF-1R, and IGFBP-3 were related to different clinicopathological features (all P < 0.05). Cox multivariate analysis results showed that methylation status of IGF-1, IGF-1R, and IGF-1 + IGF1R + IGFBP3 ; expressions of IGF-1 and IGF-1R protein; infiltration depth; and lymph node metastasis (LNM) were independent factors of EC prognosis. Our study demonstrated that methylation of IGF-1

Regulation of dendritic cell function by insulin/IGF-1/PI3K/Akt signaling through klotho expression.

PubMed

Xuan, Nguyen Thi; Hoang, Nguyen Huy; Nhung, Vu Phuong; Duong, Nguyen Thuy; Ha, Nguyen Hai; Hai, Nong Van

2017-06-01

Insulin or insulin-like growth factor 1 (IGF-1) promotes the activation of phosphoinositide 3 kinase (PI3K)/Akt signaling in immune cells including dendritic cells (DCs), the most potent professional antigen-presenting cells for naive T cells. Klotho, an anti-aging protein, participates in the regulation of the PI3K/Akt signaling, thus the Ca 2+ -dependent migration is reduced in klotho-deficient DCs. The present study explored the effects of insulin/IGF-1 on DC function through klotho expression. To this end, the mouse bone marrow cells were isolated and cultured with GM-CSF to attain bone marrow-derived DCs (BMDCs). Cells were treated with insulin or IGF-1 and followed by stimulating with lipopolysaccharides (LPS). Tumor necrosis factor (TNF)-α formation was examined by enzyme-linked immunosorbent assay (ELISA). Phagocytosis was analyzed by FITC-dextran uptake assay. The expression of klotho was determined by quantitative PCR, immunoprecipitation and western blotting. As a result, treatment of the cells with insulin/IGF-1 resulted in reducing the klotho expression as well as LPS-stimulated TNF-α release and increasing the FITC-dextran uptake but unaltering reactive oxygen species (ROS) production in BMDCs. The effects were abolished by using pharmacological inhibition of PI3K/Akt with LY294002 and paralleled by transfecting DCs with klotho siRNA. In conclusion, the regulation of klotho sensitive DC function by IGF-1 or insulin is mediated through PI3K/Akt signaling pathway in BMDCs.

Intracellular Insulin-like Growth Factor-I Induces Bcl-2 Expression in Airway Epithelial Cells 1

PubMed Central

Chand, Hitendra S.; Harris, Jennifer Foster; Mebratu, Yohannes; Chen, Yangde; Wright, Paul S.; Randell, Scott H.; Tesfaigzi, Yohannes

2012-01-01

Bcl-2, a prosurvival protein, regulates programmed cell death during development and repair processes, and can be oncogenic when cell proliferation is deregulated. The present study investigated what factors modulate Bcl-2 expression in airway epithelial cells and identified the pathways involved. Microarray analysis of mRNA from airway epithelial cells captured by laser microdissection showed that increased expression of IL-1β and IGF-1 coincided with induced Bcl-2 expression compared to controls. Treatment of cultured airway epithelial cells with IL-1β and IGF-1 induced Bcl-2 expression by increasing Bcl-2 mRNA stability with no discernible changes in promoter activity. Silencing the IGF-1 expression using shRNA showed that intracellular (IC)-IGF-1 was increasing Bcl-2 expression. Blocking EGFR or IGF-1R activation also suppressed IC-IGF-1, and abolished the Bcl-2 induction. Induced expression and co-localization of IC-IGF-1 and Bcl-2 were observed in airway epithelial cells of mice exposed to LPS or cigarette smoke and of patients with cystic fibrosis and chronic bronchitis but not in the respective controls. These studies demonstrate that IC-IGF-1 induces Bcl-2 expression in epithelial cells via IGF-1R and EGFR pathways, and targeting IC-IGF-1 could be beneficial to treat chronic airway diseases. PMID:22461702

Cloning, characterization and tissue specific expression of Amur tiger (Panthera tigris altaica) IGF-I.

PubMed

Hu, Xi-Lian; Zhu, Mu-Yuan; Zhang, Zhi-He; Hou, Rong; Shen, Fu-Jun; Li, Fu-Zhen; Zhang, An-Ju

2006-08-01

Insulin-like growth factor I (IGF-I) plays an important role in regulating gonad function, which is essential for normal reproduction in animals, especially in sexual receptivity and reproductive behavior. In this study, a cDNA encoding Amur tiger (Panthera tigris altaica) IGF-I was isolated from liver total RNA using RT-PCR. The IGF-I cDNA of Amur tiger (ATIGF-I) was highly homologous to that of other animals, 84.8% to rat, 93.7% to human and horse. Alignment analysis showed that the cysteine residues and many amino acid residues of putative mature ATIGF-I are highly conserved in mammalian species, confirming the high sequence homology observed in other species. DNA encoding the mature ATIGF-I peptide was ligated with pET-DsbA expression vector and highly expressed in Escherichia coli BL21 with IPTG induction. The recombinant proteins expressed existed mostly in the soluble protein fraction, and were purified with metal affinity resins. Western blotting confirmed that the recombinant proteins reacted with antibodies against IGF-I. The results obtained here should be useful for large-scale production of biological active ATIGF-I protein, as well as for further research on growth, development, and reproduction in the Amur tiger. Tissue specific expression of ATIGF-I mRNA in the Amur tiger was examined by reverse transcription-polymerase chain reaction (RT-PCR), The major ATIGF-I mRNA expression tissue was the liver, while medium signals were found in the uterus, ovary, and pituitary, and minor signals were detected in various tissues including the heart, spleen, pancreas, and kidney. The results indicate that IGF-I might play an important role in the reproductive system and in cub development in the Amur tiger.

The oncogenic triangle of HMGA2, LIN28B and IGF2BP1 antagonizes tumor-suppressive actions of the let-7 family.

PubMed

Busch, Bianca; Bley, Nadine; Müller, Simon; Glaß, Markus; Misiak, Danny; Lederer, Marcell; Vetter, Martina; Strauß, Hans-Georg; Thomssen, Christoph; Hüttelmaier, Stefan

2016-05-05

The tumor-suppressive let-7 microRNA family targets various oncogene-encoding mRNAs. We identify the let-7 targets HMGA2, LIN28B and IGF2BP1 to form a let-7 antagonizing self-promoting oncogenic triangle. Surprisingly, 3'-end processing of IGF2BP1 mRNAs is unaltered in aggressive cancers and tumor-derived cells although IGF2BP1 synthesis was proposed to escape let-7 attack by APA-dependent (alternative polyadenylation) 3' UTR shortening. However, the expression of the triangle factors is inversely correlated with let-7 levels and promoted by LIN28B impairing let-7 biogenesis. Moreover, IGF2BP1 enhances the expression of all triangle factors by recruiting the respective mRNAs in mRNPs lacking AGO proteins and let-7 miRNAs. This indicates that the downregulation of let-7, largely facilitated by LIN28B upregulation, and the protection of let-7 target mRNAs by IGF2BP1-directed shielding in mRNPs synergize in enhancing the expression of triangle factors. The oncogenic potential of this triangle was confirmed in ovarian cancer (OC)-derived ES-2 cells transduced with let-7 targeting decoys. In these, the depletion of HMGA2 only diminishes tumor cell growth under permissive conditions. The depletion of LIN28B and more prominently IGF2BP1 severely impairs tumor cell viability, self-renewal and 2D as well as 3D migration. In conclusion, this suggests the targeting of the HMGA2-LIN28B-IGF2BP1 triangle as a promising strategy in cancer treatment. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Dietary protein-induced hepatic IGF-1 secretion mediated by PPARγ activation.

PubMed

Wan, Xiaojuan; Wang, Songbo; Xu, Jingren; Zhuang, Lu; Xing, Kongping; Zhang, Mengyuan; Zhu, Xiaotong; Wang, Lina; Gao, Ping; Xi, Qianyun; Sun, Jiajie; Zhang, Yongliang; Li, Tiejun; Shu, Gang; Jiang, Qingyan

2017-01-01

Dietary protein or amino acid (AA) is a crucial nutritional factor to regulate hepatic insulin-like growth factor-1 (IGF-1) expression and secretion. However, the underlying intracellular mechanism by which dietary protein or AA induces IGF-1 expression remains unknown. We compared the IGF-1 gene expression and plasma IGF-1 level of pigs fed with normal crude protein (CP, 20%) and low-protein levels (LP, 14%). RNA sequencing (RNA-seq) was performed to detect transcript expression in the liver in response to dietary protein. The results showed that serum concentrations and mRNA levels of IGF-1 in the liver were higher in the CP group than in the LP group. RNA-seq analysis identified a total of 1319 differentially expressed transcripts (667 upregulated and 652 downregulated), among which the terms "oxidative phosphorylation", "ribosome", "gap junction", "PPAR signaling pathway", and "focal adhesion" were enriched. In addition, the porcine primary hepatocyte and HepG2 cell models also demonstrated that the mRNA and protein levels of IGF-1 and PPARγ increased with the increasing AA concentration in the culture. The PPARγ activator troglitazone increased IGF-1 gene expression and secretion in a dose dependent manner. Furthermore, inhibition of PPARγ effectively reversed the effects of the high AA concentration on the mRNA expression of IGF-1 and IGFBP-1 in HepG2 cells. Moreover, the protein levels of IGF-1 and PPARγ, as well as the phosphorylation of mTOR, significantly increased in HepG2 cells under high AA concentrations. mTOR phosphorylation can be decreased by the mTOR antagonist, rapamycin. The immunoprecipitation results also showed that high AA concentrations significantly increased the interaction of mTOR and PPARγ. In summary, PPARγ plays an important role in the regulation of IGF-1 secretion and gene expression in response to dietary protein.

Molecular function of microtubule-associated protein 2 for filial imprinting in domestic chicks (Gallus gallus domesticus).

PubMed

Yamaguchi, Shinji; Katagiri, Sachiko; Aoki, Naoya; Iikubo, Eiji; Kitajima, Takaaki; Matsushima, Toshiya; Homma, Koichi J

2011-01-01

RNA interference (RNAi)-mediated gene-silencing can be a tool for elucidating the role of genes in the neural basis of behavioral plasticity. Previously, we reported that exogenous DNA could be successfully delivered into newly-hatched chick brains via electroporation. Here, we used this in vivo gene-transfer technique and showed that transfected microRNA vectors preferentially silence exogenous DNA expression in neuronal cells. Using this system, the up-regulation of microtubule-associated protein 2 (MAP2) accompanying filial imprinting was suppressed in vivo, which impaired the filial imprinting in chicks. In addition, the phosphorylation of MAP2 was found to increase in parallel with filial imprinting, and lithium chloride, an inhibitor of glycogen synthase kinase 3 (GSK3), was found to impair filial imprinting. Our results suggest that the regulation of MAP2 expression and its phosphorylation are required for filial imprinting and may modify microtubule stability, thereby leading to cytoskeletal reorganization during imprinting. This in vivo RNAi-mediated gene-silencing system will facilitate the analysis of gene function in the living chick brain and provides further clues regarding the molecular mechanisms underpinning avian learning. Copyright © 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

[The influence of partial dorsal root rhizotomy on IGF-I expression in spared root ganglion and spinal cord].

PubMed

Wang, Wei-min; Guan, Yu-guang; Liu, Fen; Wang, Ting-hua; Xu, Xin-yun; Ke, Qing; Lu, Yong-chao; Yuan, Yuan

2005-01-01

To explore the temporospatial changes of IGF-I expression in the spared dorsal root ganglia (DRG, L6) on the operated side and un-operated side, in the spinal lamina II (L3, L5, L6) and Clarke's nucleus (L3) of the adult cats that have undergone partial dorsal rhizotomy, and compare them against those of the normal adult cats so as to unveil the relation between IGF-I and the plasticity of spinal cord. Fifteen male adult cats were divided into three groups. The cats of two groups were subjected to unilateral partial dorsal root rhizotomy (L1-L5, L7-S2 DRG were sectioned, but L6 was spared) and were sacrificed at 7 days and 14 days after operation. The bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of all groups were made into frozen sections 20 microm thick. Then, the sections were stained by the immunohistochemistry ABC method using IGF-I (1:200, Santa Cruz) antibody. The distribution and the number of IGF-I positive neurons in bilateral spared DRG (L6) on the operated/un-operated side, in spinal lamina I (L3, L5, L6) and in Clarke' nucleus (L3) of each animal were observed and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. (1) Seven days after partial dorsal root rhizotomy, the number of IGF-I positive neurons in spared DRG on the operated side declined as compared with that of normal group (P<0.05), but it was not significantly different from that of L6 spared DRG on the un-operated side (P>0.05). On the 14th day, the IGF-I expression in neurons of L6 DRG on the operated side was significantly lower than that of normal group and that of L6 spared DRG on the unoperated side (P<0.01), but it was not significantly different from that of the 7th day group (P>0.05). (2) There was no difference in number of IGF-I positive neuron in L3, L5, L6 spinal lamina II between normal group, 7th day post-operation group and 14th day post-operation group (P>0.05). After operation, IGF-I expression in Clarke's nucleus declined on the 7

A human imprinting centre demonstrates conserved acquisition but diverged maintenance of imprinting in a mouse model for Angelman syndrome imprinting defects.

PubMed

Johnstone, Karen A; DuBose, Amanda J; Futtner, Christopher R; Elmore, Michael D; Brannan, Camilynn I; Resnick, James L

2006-02-01

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are caused by the loss of imprinted gene expression from chromosome 15q11-q13. Imprinted gene expression in the region is regulated by a bipartite imprinting centre (IC), comprising the PWS-IC and the AS-IC. The PWS-IC is a positive regulatory element required for bidirectional activation of a number of paternally expressed genes. The function of the AS-IC appears to be to suppress PWS-IC function on the maternal chromosome through a methylation imprint acquired during female gametogenesis. Here we have placed the entire mouse locus under the control of a human PWS-IC by targeted replacement of the mouse PWS-IC with the equivalent human region. Paternal inheritance of the human PWS-IC demonstrates for the first time that a positive regulatory element in the PWS-IC has diverged. These mice show postnatal lethality and growth deficiency, phenotypes not previously attributed directly to the affected genes. Following maternal inheritance, the human PWS-IC is able to acquire a methylation imprint in mouse oocytes, suggesting that acquisition of the methylation imprint is conserved. However, the imprint is lost in somatic cells, showing that maintenance has diverged. This maternal imprinting defect results in expression of maternal Ube3a-as and repression of Ube3a in cis, providing evidence that Ube3a is regulated by its antisense and creating the first reported mouse model for AS imprinting defects.

IGF2 differentially methylated region hypomethylation in relation to pathological and molecular features of serrated lesions

PubMed Central

Naito, Takafumi; Nosho, Katsuhiko; Ito, Miki; Igarashi, Hisayoshi; Mitsuhashi, Kei; Yoshii, Shinji; Aoki, Hironori; Nomura, Masafumi; Sukawa, Yasutaka; Yamamoto, Eiichiro; Adachi, Yasushi; Takahashi, Hiroaki; Hosokawa, Masao; Fujita, Masahiro; Takenouchi, Toshinao; Maruyama, Reo; Suzuki, Hiromu; Baba, Yoshifumi; Imai, Kohzoh; Yamamoto, Hiroyuki; Ogino, Shuji; Shinomura, Yasuhisa

2014-01-01

AIM: To investigate insulin-like growth factor 2 (IGF2) differentially methylated region (DMR)0 hypomethylation in relation to clinicopathological and molecular features in colorectal serrated lesions. METHODS: To accurately analyze the association between the histological types and molecular features of each type of serrated lesion, we consecutively collected 1386 formalin-fixed paraffin-embedded tissue specimens that comprised all histological types [hyperplastic polyps (HPs, n = 121), sessile serrated adenomas (SSAs, n = 132), traditional serrated adenomas (TSAs, n = 111), non-serrated adenomas (n = 195), and colorectal cancers (CRCs, n = 827)]. We evaluated the methylation levels of IGF2 DMR0 and long interspersed nucleotide element-1 (LINE-1) in HPs (n = 115), SSAs (n = 120), SSAs with cytological dysplasia (n = 10), TSAs (n = 91), TSAs with high-grade dysplasia (HGD) (n = 15), non-serrated adenomas (n = 80), non-serrated adenomas with HGD (n = 105), and CRCs (n = 794). For the accurate quantification of the relative methylation levels (scale 0%-100%) of IGF2 DMR0 and LINE-1, we used bisulfite pyrosequencing method. Tumor specimens were analyzed for microsatellite instability, KRAS (codons 12 and 13), BRAF (V600E), and PIK3CA (exons 9 and 20) mutations; MLH1 and MGMT methylation; and IGF2 expression by immunohistochemistry. RESULTS: The distribution of the IGF2 DMR0 methylation level in 351 serrated lesions and 185 non-serrated adenomas (with or without HGD) was as follows: mean 61.7, median 62.5, SD 18.0, range 5.0-99.0, interquartile range 49.5-74.4. The IGF2 DMR0 methylation level was divided into quartiles (Q1 ≥ 74.5, Q2 62.6-74.4, Q3 49.6-62.5, Q4 ≤ 49.5) for further analysis. With regard to the histological type, the IGF2 DMR0 methylation levels of SSAs (mean ± SD, 73.1 ± 12.3) were significantly higher than those of HPs (61.9 ± 20.5), TSAs (61.6 ± 19.6), and non-serrated adenomas (59.0 ± 15.8) (P < 0.0001). The IGF2 DMR0 methylation level was

CD52, CD22, CD26, EG5 and IGF-1R expression in thymic malignancies.

PubMed

Remon, J; Abedallaa, N; Taranchon-Clermont, E; Bluthgen, V; Lindsay, C R; Besse, B; Thomas de Montpréville, V

2017-06-01

Thymic epithelial tumours are rare cancers for which new treatment options are required. Identification of putative predictive markers is important for developing clinical trials. We studied the expression of five putative predictive biomarkers, potentially actionable by approved experimental drugs. CD52, CD22, CD26, EG5, and IGF-1R expression were investigated by immunohistochemistry in formalin-fixed surgical samples of thymic epithelial tumour patients. All samples containing 10% positive epithelial tumour cells, independent of tumour cell intensity, were considered as positive. Correlation with histological subtype was performed. 106 surgical samples (89 thymomas, 12 thymic carcinoma, and 5 thymic neuroendocrine tumours) were evaluated. Overall, CD52, CD22, CD26, EG5 and IGF-1R expression was observed in 7%, 42%, 25%, 42% and 77% of samples, respectively. CD52 expression was more frequent in B2 and B3 thymoma. All TET subtypes stained for CD22, mainly AB thymoma (68%). CD26 expression also correlated with AB thymoma (68%), and A thymoma (50%) subtype, while IGFR1 was the most common marker expressed by thymic carcinoma samples (92%), followed by EG5 (60%). Only EG5 expression was significantly higher in thymic carcinomas than in thymomas (75% vs. 38%, p=0.026). Our data were consistent with a previous study of IGF-1R expression. Based on their expression, activity of agents targeting CD52, CD 22, CD26 and EG5 could be further explored in TET patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Altered imprinted gene expression and methylation patterns in mid-gestation aborted cloned porcine fetuses and placentas.

PubMed

Zhang, Xiaoyang; Wang, Dongxu; Han, Yang; Duan, Feifei; Lv, Qinyan; Li, Zhanjun

2014-11-01

To determine the expression patterns of imprinted genes and their methylation status in aborted cloned porcine fetuses and placentas. RNA and DNA were prepared from fetuses and placentas that were produced by SCNT and controls from artificial insemination. The expression of 18 imprinted genes was determined by quantitative real-time PCR (q-PCR). Bisulfite sequencing PCR (BSP) was conducted to determine the methylation status of PRE-1 short interspersed repetitive element (SINE), satellite DNA and H19 differentially methylated region 3 (DMR3). The weight, imprinted gene expression and genome-wide DNA methylation patterns were compared between the mid-gestation aborted and normal control samples. The results showed hypermethylation of PRE-1 and satellite sequences, the aberrant expression of imprinted genes, and the hypomethylation of H19 DMR3 occurred in mid-gestation aborted fetuses and placentas. Cloned pigs generated by somatic cell nuclear transfer (SCNT) showed a greater ratio of early abortion during mid-gestation than did normal controls because of the incomplete epigenetic reprogramming of the donor cells. Altered expression of imprinted genes and the hypermethylation profile of the repetitive regions (PRE-1 and satellite DNA) may be associated with defective development and early abortion of cloned pigs, emphasizing the importance of epigenetics during pregnancy and implications thereof for patient-specific embryonic stem cells for human therapeutic cloning and improvement of human assisted reproduction.

Genomic Imprinting in Mammals

PubMed Central

Barlow, Denise P.

2014-01-01

Genomic imprinting affects a subset of genes in mammals and results in a monoallelic, parental-specific expression pattern. Most of these genes are located in clusters that are regulated through the use of insulators or long noncoding RNAs (lncRNAs). To distinguish the parental alleles, imprinted genes are epigenetically marked in gametes at imprinting control elements through the use of DNA methylation at the very least. Imprinted gene expression is subsequently conferred through lncRNAs, histone modifications, insulators, and higher-order chromatin structure. Such imprints are maintained after fertilization through these mechanisms despite extensive reprogramming of the mammalian genome. Genomic imprinting is an excellent model for understanding mammalian epigenetic regulation. PMID:24492710

The effects of an acute exercise bout on GH and IGF-1 in prediabetic and healthy African Americans: A pilot study investigating gene expression.

PubMed

Berry, Nathaniel T; Hubal, Monica; Wideman, Laurie

2018-01-01

The incidence of pre-diabetes (PD) and Type-2 Diabetes Mellitus (T2D) is a worldwide epidemic. African American (AA) individuals are disproportionately more likely to become diabetic than other ethnic groups. Over the long-term, metabolic complications related to diabetes result in significant alterations in growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Considering the limited exercise-related studies in the area of gene expression changes with disease progression, the objective of this study was to examine differences in exercise-induced gene expression related to the GH and IGF-1 pathways in peripheral blood mononuclear cells (PBMCs) of healthy (CON) and PD AA individuals. Ten subjects [5 PD (age = 35±9.3 yr, BMI = 32.1±4.0, FBG = 101.8±1.3 mg/dl) and 5 CON (age = 31±9.4 yr, BMI = 29.4±5.2, FBG = 82.8±9.7 mg/dl)] had blood drawn for RNA isolation prior to exercise (Pre), immediately following acute moderate intensity exercise on a treadmill (Post-1), 6-hours post (Post-6), and 24-hours post (Post-24). Isolation of mRNA from PBMCs was performed using ficoll separation, while the profiling of mRNA expression was performed using Illumina beadchip arrays with standard protocols. Scan results were statistically analyzed for a specific list of genes related to GH and IGF-1. GH and IGF-1 protein levels were also assessed in each sample. To address issues of normality, all GH and IGF-1 data were log-transformed prior to analysis. Statistical significance was set at p<0.05. Group differences for GH2 variant 2 (p = 0.070) and GH2 variant 3 (p = 0.059) were coupled with significant alterations in IGF-1 mRNA over time (p = 0.024). A significant interaction between group and time was observed for GHRH mRNA (p = 0.008). No group differences were observed in GH AUC (p = 0.649), ΔGH (p = 0.331), GHrec (p = 0.294), or IGF-1 AUC (p = 0.865), representing a similar exercise-induced GH and IGF-1 response for both groups. Analysis of GH and IGF-1 related

The Effects of IGF-1 on Trk Expressing DRG Neurons with HIV-gp120- Induced Neurotoxicity.

PubMed

Li, Hao; Liu, Zhen; Chi, Heng; Bi, Yanwen; Song, Lijun; Liu, Huaxiang

2016-01-01

HIV envelope glycoprotein gp120 is the main protein that causes HIVassociated sensory neuropathy. However, the underlying mechanisms of gp120-induced neurotoxicity are still unclear. There are lack effective treatments for relieving HIV-related neuropathic symptoms caused by gp120-induced neurotoxicity. In the present study, tyrosine kinase receptor (Trk)A, TrkB, and TrkC expression in primary cultured dorsal root ganglion (DRG) neurons with gp120-induced neurotoxicity was investigated. The effects of IGF-1 on distinct Trk-positive DRG neurons with gp120-induced neurotoxicity were also determined. The results showed that gp120 not only dose-dependently induced DRG neuronal apoptosis and inhibited neuronal survival and neurite outgrowth, but also decreased distinct Trk expression levels. IGF-1 rescued DRG neurons from apoptosis and improved neuronal survival of gp120 neurotoxic DRG neurons in vitro. IGF-1 also improved TrkA and TrkB, but not TrkC, expression in gp120 neurotoxic conditions. The effects of IGF-1 could be blocked by preincubation with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. These results suggested that gp120 may have a wide range of neurotoxicity on different subpopulations of DRG neurons, while IGF-1 might only relieve some subpopulations of DRG neurons with gp120-induced neurotoxicity. These data provide novel information of mechanisms of gp120 neurotoxicity on primary sensory neurons and the potential therapeutic effects of IGF-1 on gp120-induced neurotoxicity.

Study on the relationship between the expression of IGF-1 in umbilical cord blood and abnormal glucose metabolism during pregnancy.

PubMed

Liu, K; Wu, H-Y; Xu, Y-H

2017-02-01

To explore the relationship between the expression of insulin-like growth factor-1 (IGF-1) in neonatal umbilical cord blood and abnormal glucose metabolism during pregnancy. We have selected 63 cases of delivery randomly, term birth and maternal from January 2015 to January 2016 in our hospital, gestational diabetes mellitus for Group A, abnormal gestational glucose tolerance for Group B and normal for Group C with 21 cases in each group. The venous blood samples were collected from all the pregnant females 2 weeks before delivery, and the levels of HbA1c in serum were detected by Elisa method. During the delivery, the umbilical cord blood was collected and the levels of IGF-1 were measured by double site immune enzyme analysis. The neonatal weight was recorded and the correlation analysis was made in respect of the measurement results. The level of HbA1c in Group A was significantly higher than that in Group C (p < 0.05); IGF-1 level and neonatal weight of Group B were significantly higher than that of Group C (p < 0.05), IGF-1 has a significant correlation with neonatal weight in Group C, and HbA1c and IGF-1 were positively correlated (p < 0.05); IGF-1 was positively correlated with neonatal weight in Group A and Group B (p < 0.05). There was a significant positive correlation between the IGF-1 level of neonatal umbilical cord blood and the neonatal weight (p < 0.05). Also, the level of HbA1c was positively correlated with the level of IGF-1 in neonatal umbilical cord blood at the end of pregnancy (p < 0.05). The expression level of IGF-1 in the final stage of pregnant females can be detected to predict the expression level of IGF-1 in newborn infants and then the growth status of the fetus can be obtained.

Small Molecules that Suppress IGF-Activated Prostate Cancers

DTIC Science & Technology

2006-04-01

selectively impair the growth of IGF2-overexpressing hepatocellular carcinoma cells. For cell viability assays, IGF2-expressing cells were plated at a...produced at high levels in liver tumors (27). We identified three chemically analogous compounds that killed IGF2-overexpressing hepatocellular carcinoma cells... hepatocellular carcinoma cell lines that we recently characterized2 indicated that one of the three chemi- cals, 94G6, exhibited the highest cytotoxicity

Effects of different dietary intake on mRNA levels of MSTN, IGF-I, and IGF-II in the skeletal muscle of Dorper and Hu sheep hybrid F1 rams.

PubMed

Xing, H J; Wang, Z Y; Zhong, B S; Ying, S J; Nie, H T; Zhou, Z R; Fan, Y X; Wang, F

2014-07-24

MSTN, IGF-І(insulin-like growth factor-І) and IGF-II (insulin-like growth factor-II) regulate skeletal muscle growth. This study investigated the effects of different dietary intake levels on skeletal muscles. Sheep was randomly assigned to 3 feeding groups: 1) the maintenance diet (M), 2) 1.4 x the maintenance diet (1.4M), and 3) 2.15 x the maintenance diet (2.15M). Before slaughtering the animals, blood samples were collected to measure plasma urea, growth hormone, and insulin concentrations. After slaughtering, the longissimus dorsi, semitendinosus, semimembranosus, gastrocnemius, soleus, and chest muscle were removed to record various parameters, including the mRNA expression levels of MSTN and IGFs, in addition to skeletal muscle fiber diameter and cross-sectional area. The result showed that as dietary intake improved, the mRNA expression levels of MSTN and IGF-II decreased, whereas IGF-Іexpression increased. The mRNA expression levels of MSTN and IGFs were significantly different in the same skeletal muscle under different dietary intake. The skeletal muscle fiber diameter and cross-sectional area increased with greater dietary intake, as observed for the mRNA expression of IGF-І; however, it contrasted to that observed for the mRNA expression of MSTN and IGF-II. In conclusion, dietary intake levels have a certain influence on MSTN and IGFs mRNA expression levels, in addition to skeletal muscle fiber diameter and cross-sectional area. This study contributes valuable information for enhancing the molecular-based breeding of sheep.

Depression in pregnancy, infant birth weight and DNA methylation of imprint regulatory elements

PubMed Central

Liu, Ying; Murphy, Susan K.; Murtha, Amy P.; Fuemmeler, Bernard F.; Schildkraut, Joellen; Huang, Zhiqing; Overcash, Francine; Kurtzberg, Joanne; Jirtle, Randy; Iversen, Edwin S.; Forman, Michele R.; Hoyo, Cathrine

2012-01-01

Depressed mood in pregnancy has been linked to low birth weight (LBW, < 2,500 g), a risk factor for adult-onset chronic diseases in offspring. We examined maternal depressed mood in relation to birth weight and evaluated the role of DNA methylation at regulatory sequences of imprinted genes in this association. We measured depressed mood among 922 pregnant women using the CES-D scale and obtained birth weight data from hospital records. Using bisulfite pyrosequencing of cord blood DNA from 508 infants, we measured methylation at differentially methylated regions (DMRs) regulating imprinted genes IGF2/H19, DLK1/MEG3, MEST, PEG3, PEG10/SGCE, NNAT and PLAGL1. Multiple regression models were used to examine the relationship between depressed mood, birth weight and DMR methylation levels. Depressed mood was associated with a more that 3-fold higher risk of LBW, after adjusting for delivery mode, parity, education, cigarette smoking, folic acid use and preterm birth. The association may be more pronounced in offspring of black women and female infants. Compared with infants of women without depressed mood, infants born to women with severe depressed mood had a 2.4% higher methylation at the MEG3 DMR. Whereas LBW infants had 1.6% lower methylation at the IGF2 DMR, high birth weight (> 4,500 g) infants had 5.9% higher methylation at the PLAGL1 DMR compared with normal birth weight infants. Our findings confirm that severe maternal depressed mood in pregnancy is associated with LBW, and that MEG3 and IGF2 plasticity may play important roles. PMID:22677950

IGF-1 Receptor Expression on Circulating Osteoblast Progenitor Cells Predicts Tissue-Based Bone Formation Rate and Response to Teriparatide in Premenopausal Women With Idiopathic Osteoporosis.

PubMed

Cohen, Adi; Kousteni, Stavroula; Bisikirska, Brygida; Shah, Jayesh G; Manavalan, J Sanil; Recker, Robert R; Lappe, Joan; Dempster, David W; Zhou, Hua; McMahon, Donald J; Bucovsky, Mariana; Kamanda-Kosseh, Mafo; Stubby, Julie; Shane, Elizabeth

2017-06-01

We have previously reported that premenopausal women with idiopathic osteoporosis (IOP) have profound microarchitectural deficiencies and heterogeneous bone remodeling. Those with the lowest bone formation rate have higher baseline serum insulin-like growth factor-1 (IGF-1) levels and less robust response to teriparatide. Because IGF-1 stimulates bone formation and is critical for teriparatide action on osteoblasts, these findings suggest a state of IGF-1 resistance in some IOP women. To further investigate the hypothesis that osteoblast and IGF-1-related mechanisms mediate differential responsiveness to teriparatide in IOP, we studied circulating osteoblast progenitor (COP) cells and their IGF-1 receptor (IGF-1R) expression. In premenopausal women with IOP, peripheral blood mononuclear cells (PBMCs) were obtained at baseline (n = 25) and over 24 months of teriparatide treatment (n = 11). Flow cytometry was used to identify and quantify COPs (non-hematopoetic lineage cells expressing osteocalcin and RUNX2) and to quantify IGF-1R expression levels. At baseline, both the percent of PBMCs that were COPs (%COP) and COP cell-surface IGF-1R expression correlated directly with several histomorphometric indices of bone formation in tetracycline-labeled transiliac biopsies. In treated subjects, both %COP and IGF-1R expression increased promptly after teriparatide, returning toward baseline by 18 months. Although neither baseline %COP nor increase in %COP after 3 months predicted the bone mineral density (BMD) response to teriparatide, the percent increase in IGF-1R expression on COPs at 3 months correlated directly with the BMD response to teriparatide. Additionally, lower IGF-1R expression after teriparatide was associated with higher body fat, suggesting links between teriparatide resistance, body composition, and the GH/IGF-1 axis. In conclusion, these assays may be useful to characterize bone remodeling noninvasively and may serve to predict early response to

40 YEARS of IGF1: Understanding the tissue-specific roles of IGF1/IGF1R in regulating metabolism using the Cre/loxP system.

PubMed

Kineman, Rhonda D; Del Rio-Moreno, Mercedes; Sarmento-Cabral, André

2018-07-01

It is clear that insulin-like growth factor-1 (IGF1) is important in supporting growth and regulating metabolism. The IGF1 found in the circulation is primarily produced by the liver hepatocytes, but healthy mature hepatocytes do not express appreciable levels of the IGF1 receptor (IGF1R). Therefore, the metabolic actions of IGF1 are thought to be mediated via extra-hepatocyte actions. Given the structural and functional homology between IGF1/IGF1R and insulin receptor (INSR) signaling, and the fact that IGF1, IGF1R and INSR are expressed in most tissues of the body, it is difficult to separate out the tissue-specific contributions of IGF1/IGF1R in maintaining whole body metabolic function. To circumvent this problem, over the last 20 years, investigators have taken advantage of the Cre/loxP system to manipulate IGF1/IGF1R in a tissue-dependent, and more recently, an age-dependent fashion. These studies have revealed that IGF1/IGF1R can alter extra-hepatocyte function to regulate hormonal inputs to the liver and/or alter tissue-specific carbohydrate and lipid metabolism to alter nutrient flux to liver, where these actions are not mutually exclusive, but serve to integrate the function of all tissues to support the metabolic needs of the organism. © 2018 Society for Endocrinology.

Zcchc11 Uridylates Mature miRNAs to Enhance Neonatal IGF-1 Expression, Growth, and Survival

PubMed Central

Kozlowski, Elyse; Matsuura, Kori Y.; Ferrari, Joseph D.; Morris, Samantha A.; Powers, John T.; Daley, George Q.; Quinton, Lee J.; Mizgerd, Joseph P.

2012-01-01

The Zcchc11 enzyme is implicated in microRNA (miRNA) regulation. It can uridylate let-7 precursors to decrease quantities of the mature miRNA in embryonic stem cell lines, suggested to mediate stem cell maintenance. It can uridylate mature miR-26 to relieve silencing activity without impacting miRNA content in cancer cell lines, suggested to mediate cytokine and growth factor expression. Broader roles of Zcchc11 in shaping or remodeling the miRNome or in directing biological or physiological processes remain entirely speculative. We generated Zcchc11-deficient mice to address these knowledge gaps. Zcchc11 deficiency had no impact on embryogenesis or fetal development, but it significantly decreased survival and growth immediately following birth, indicating a role for this enzyme in early postnatal fitness. Deep sequencing of small RNAs from neonatal livers revealed roles of this enzyme in miRNA sequence diversity. Zcchc11 deficiency diminished the lengths and terminal uridine frequencies for diverse mature miRNAs, but it had no influence on the quantities of any miRNAs. The expression of IGF-1, a liver-derived protein essential to early growth and survival, was enhanced by Zcchc11 expression in vitro, and miRNA silencing of IGF-1 was alleviated by uridylation events observed to be Zcchc11-dependent in the neonatal liver. In neonatal mice, Zcchc11 deficiency significantly decreased IGF-1 mRNA in the liver and IGF-1 protein in the blood. We conclude that the Zcchc11-mediated terminal uridylation of mature miRNAs is pervasive and physiologically significant, especially important in the neonatal period for fostering IGF-1 expression and enhancing postnatal growth and survival. We propose that the miRNA 3′ terminus is a regulatory node upon which multiple enzymes converge to direct silencing activity and tune gene expression. PMID:23209448

Increased linear bone growth by GH in the absence of SOCS2 is independent of IGF-1.

PubMed

Dobie, Ross; Ahmed, Syed F; Staines, Katherine A; Pass, Chloe; Jasim, Seema; MacRae, Vicky E; Farquharson, Colin

2015-11-01

Growth hormone (GH) signaling is essential for postnatal linear bone growth, but the relative importance of GHs actions on the liver and/or growth plate cartilage remains unclear. The importance of liver derived insulin like-growth factor-1 (IGF-1) for endochondral growth has recently been challenged. Here, we investigate linear growth in Suppressor of Cytokine Signaling-2 (SOCS2) knockout mice, which have enhanced growth despite normal systemic GH/IGF-1 levels. Wild-type embryonic ex vivo metatarsals failed to exhibit increased linear growth in response to GH, but displayed increased Socs2 transcript levels (P < 0.01). In the absence of SOCS2, GH treatment enhanced metatarsal linear growth over a 12 day period. Despite this increase, IGF-1 transcript and protein levels were not increased in response to GH. In accordance with these data, IGF-1 levels were unchanged in GH-challenged postnatal Socs2(-/-) conditioned medium despite metatarsals showing enhanced linear growth. Growth-plate Igf1 mRNA levels were not elevated in juvenile Socs2(-/-) mice. GH did however elevate IGF-binding protein 3 levels in conditioned medium from GH challenged metatarsals and this was more apparent in Socs2(-/-) metatarsals. GH did not enhance the growth of Socs2(-/-) metatarsals when the IGF receptor was inhibited, suggesting that IGF receptor mediated mechanisms are required. IGF-2 may be responsible as IGF-2 promoted metatarsal growth and Igf2 expression was elevated in Socs2(-/-) (but not WT) metatarsals in response to GH. These studies emphasise the critical importance of SOCS2 in regulating GHs ability to promote bone growth. Also, GH appears to act directly on the metatarsals of Socs2(-/-) mice, promoting growth via a mechanism that is independent of IGF-1. © 2014 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

The anti-apoptotic effect of IGF-1 on tissue resident stem cells is mediated via PI3-kinase dependent secreted frizzled related protein 2 (Sfrp2) release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gehmert, Sebastian; Sadat, Sanga; Song Yaohua

2008-07-11

Previous studies suggest that IGF-1 may be used as an adjuvant to stem cell transfer in order to improve cell engraftment in ischemic tissue. In the current study, we investigated the effect of IGF-1 on serum deprivation and hypoxia induced stem cell apoptosis and the possible mechanisms involved. Exposure of adipose tissue derived stem cells (ASCs) to serum deprivation and hypoxia resulted in significant apoptosis in ASC which is partially prevented by IGF-1. IGF-1's anti-apoptotic effect was abolished in ASCs transfected with Sfrp2 siRNA but not by the control siRNA. Using Western blot analysis, we demonstrated that serum deprivation andmore » hypoxia reduced the expression of nuclear {beta}-catenin, which is reversed by IGF-1. IGF-1's effect on {beta}-catenin expression was abolished by the presence of PI3-kinase inhibitor LY294002 or in ASCs transfected with Sfrp2 siRNA. These results suggest that IGF-1, through the release of the Sfrp2, contributes to cell survival by stabilizing {beta}-catenin.« less

IGF-1R Regulates the Extracellular Level of Active MMP-2, Pathological Neovascularization, and Functionality in Retinas of OIR Mouse Model.

PubMed

Lorenc, Valeria E; Subirada Caldarone, Paula V; Paz, María C; Ferrer, Darío G; Luna, José D; Chiabrando, Gustavo A; Sánchez, María C

2018-02-01

In ischemic proliferative diseases such as retinopathies, persistent hypoxia leads to the release of numerous neovascular factors that participate in the formation of abnormal vessels and eventually cause blindness. The upregulation and activation of metalloproteinases (MMP-2 and MMP-9) represent a final common pathway in this process. Although many regulators of the neovascular process have been identified, the complete role of the insulin-like growth factor 1 (IGF-1) and its receptor (IGF-1R) appears to be significantly more complex. In this study, we used an oxygen-induced retinopathy (OIR) mouse model as well as an in vitro model of hypoxia to study the role of MMP-2 derived from Müller glial cells (MGCs) and its relation with the IGF-1/IGF-1R system. We demonstrated that MMP-2 protein expression increased in P17 OIR mice, which coincided with the active phase of the neovascular process. Also, glutamine synthetase (GS)-positive cells were also positive for MMP-2, whereas IGF-1R was expressed by GFAP-positive cells, indicating that both proteins were expressed in MGCs. In addition, in the OIR model a single intravitreal injection of the IGF-1R blocking antibody (αIR3) administered at P12 effectively prevented pathologic neovascularization, accelerated physiological revascularization, and improved retinal functionality at P17. Finally, in MGC supernatants, the blocking antibody abolished the IGF-1 effect on active MMP-2 under normoxic and hypoxic conditions without affecting the extracellular levels of pro-MMP-2. These results demonstrate, for the first time, that the IGF-1/IGF-1R system regulates active MMP-2 levels in MGCs, thus contributing to MEC remodeling during the retinal neovascular process.

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes.

PubMed

Liu, Ping; Kong, Feng; Wang, Jue; Lu, Qinghua; Xu, Haijia; Qi, Tonggang; Meng, Juan

2015-02-01

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0-G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. Copyright © 2014 Elsevier Inc. All rights reserved.

Cryptochromes regulate IGF-1 production and signaling through control of JAK2-dependent STAT5B phosphorylation

PubMed Central

Chaudhari, Amol; Gupta, Richa; Patel, Sonal; Velingkaar, Nikkhil; Kondratov, Roman

2017-01-01

Insulin-like growth factor (IGF) signaling plays an important role in cell growth and proliferation and is implicated in regulation of cancer, metabolism, and aging. Here we report that IGF-1 level in blood and IGF-1 signaling demonstrates circadian rhythms. Circadian control occurs through cryptochromes (CRYs)—transcriptional repressors and components of the circadian clock. IGF-1 rhythms are disrupted in Cry-deficient mice, and IGF-1 level is reduced by 80% in these mice, which leads to reduced IGF signaling. In agreement, Cry-deficient mice have reduced body (∼30% reduction) and organ size. Down-regulation of IGF-1 upon Cry deficiency correlates with reduced Igf-1 mRNA expression in the liver and skeletal muscles. Igf-1 transcription is regulated through growth hormone–induced, JAK2 kinase–mediated phosphorylation of transcriptional factor STAT5B. The phosphorylation of STAT5B on the JAK2-dependent Y699 site is significantly reduced in the liver and skeletal muscles of Cry-deficient mice. At the same time, phosphorylation of JAK2 kinase was not reduced upon Cry deficiency, which places CRY activity downstream from JAK2. Thus CRYs link the circadian clock and JAK-STAT signaling through control of STAT5B phosphorylation, which provides the mechanism for circadian rhythms in IGF signaling in vivo. PMID:28100634

IGF-1-induced MMP-11 expression promotes the proliferation and invasion of gastric cancer cells through the JAK1/STAT3 signaling pathway.

PubMed

Su, Chao; Wang, Wenchang; Wang, Cunchuan

2018-05-01

The present study aimed to investigate the association between insulin-like growth factor-1 (IGF-1) and matrix metalloproteinase-11 (MMP-11) expression in gastric cancer (GC) and the underlying mechanisms in SGC-7901 cells. Reverse transcription-quantitative polymerase chain reaction analysis revealed that the expression of IGF-1 and MMP-11 was significantly upregulated in GC tissues compared with normal gastric tissue. Furthermore, IGF-1 significantly and dose-dependently promoted MMP-11. Western blotting revealed that the addition of IGF-1 to SGC-7901 cells led to an evident enhancement in signal transducer and activator of transcription 3 (STAT3), IGF-1R and Janus kinase 1 (JAK1) phosphorylation at 20 and 40 min. A decrease in the extent of the elevated expression of MMP-11 and the enhanced phosphorylation of STAT3, JAK1 and IGF-1 receptor (IGF-1R) induced by IGF-1 in SGC-7901 cells were observed following treatment with NT157 (an IGF-1R inhibitor). Furthermore, piceatannol (a JAK1 inhibitor) or small interfering RNA against STAT3 reduced the extent of the increased expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Piceatannol treatment induced the dose-dependent decline in the enhancement of STAT3 phosphorylation induced by IGF-1, indicating that the JAK1/STAT3 pathway may be implicated in the elevated expression of MMP-11 induced by IGF-1 in SGC-7901 cells. Finally, IGF-1 treatment significantly promoted the proliferation and invasion of SGC-7901 cells, which was inhibited following NT157, piceatannol or si-STAT3 treatment. The present study therefore demonstrated that IGF-1-induced MMP-11 may have facilitated the proliferation and invasion of SGC-7901 cells via the JAK1/STAT3 pathway.

Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults.

PubMed

Van de Pette, Mathew; Abbas, Allifia; Feytout, Amelie; McNamara, Gráinne; Bruno, Ludovica; To, Wilson K; Dimond, Andrew; Sardini, Alessandro; Webster, Zoe; McGinty, James; Paul, Eleanor J; Ungless, Mark A; French, Paul M W; Withers, Dominic J; Uren, Anthony; Ferguson-Smith, Anne C; Merkenschlager, Matthias; John, Rosalind M; Fisher, Amanda G

2017-01-31

Imprinted genes are regulated according to parental origin and can influence embryonic growth and metabolism and confer disease susceptibility. Here, we designed sensitive allele-specific reporters to non-invasively monitor imprinted Cdkn1c expression in mice and showed that expression was modulated by environmental factors encountered in utero. Acute exposure to chromatin-modifying drugs resulted in de-repression of paternally inherited (silent) Cdkn1c alleles in embryos that was temporary and resolved after birth. In contrast, deprivation of maternal dietary protein in utero provoked permanent de-repression of imprinted Cdkn1c expression that was sustained into adulthood and occurred through a folate-dependent mechanism of DNA methylation loss. Given the function of imprinted genes in regulating behavior and metabolic processes in adults, these results establish imprinting deregulation as a credible mechanism linking early-life adversity to later-life outcomes. Furthermore, Cdkn1c-luciferase mice offer non-invasive tools to identify factors that disrupt epigenetic processes and strategies to limit their long-term impact. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Insulin-like growth factor (IGF) signalling is required for early dorso-anterior development of the zebrafish embryo.

PubMed

Eivers, Edward; McCarthy, Karena; Glynn, Catherine; Nolan, Catherine M; Byrnes, Lucy

2004-12-01

The insulin-like growth factor (IGF) signalling pathway has been highly conserved in animal evolution and, in mammals and Xenopus, plays a key role in embryonic growth and development, with the IGF-1 receptor (IGF-1R) being a crucial regulator of the signalling cascade. Here we report the first functional role for the IGF pathway in zebrafish. Expression of mRNA coding for a dominant negative IGF-1R resulted in embryos that were small in size compared to controls and had disrupted head and CNS development. At its most extreme, this phenotype was characterized by a complete loss of head and eye structures, an absence of notochord and the presence of abnormal somites. In contrast, up-regulation of IGF signalling following injection of IGF-1 mRNA, resulted in a greatly expanded development of anterior structures at the expense of trunk and tail. IGF-1R knockdown caused a significant decrease in the expression of Otx2, Rx3, FGF8, Pax6.2 and Ntl, while excess IGF signalling expanded Otx2 expression in presumptive forebrain tissue and widened the Ntl expression domain in the developing notochord. The observation that IGF-1R knockdown reduced expression of two key organizer genes (chordin and goosecoid) suggests that IGF signalling plays a role in regulating zebrafish organizer activity. This is supported by the expression of IGF-1, IGF-2 and IGF-1R in shield-stage zebrafish embryos and the demonstration that IGF signalling influences expression of BMP2b, a gene that plays an important role in zebrafish pattern formation. Our data is consistent with a common pathway for integration of IGF, FGF8 and anti-BMPs in early vertebrate development.

IGF-1 Promotes Brn-4 Expression and Neuronal Differentiation of Neural Stem Cells via the PI3K/Akt Pathway

PubMed Central

Zhang, Xinhua; Zhang, Lei; Cheng, Xiang; Guo, Yuxiu; Sun, Xiaohui; Chen, Geng; Li, Haoming; Li, Pengcheng; Lu, Xiaohui; Tian, Meiling; Qin, Jianbing; Zhou, Hui; Jin, Guohua

2014-01-01

Our previous studies indicated that transcription factor Brn-4 is upregulated in the surgically denervated hippocampus in vivo, promoting neuronal differentiation of hippocampal neural stem cells (NSCs) in vitro. The molecules mediating Brn-4 upregulation in the denervated hippocampus remain unknown. In this study we examined the levels of insulin-like growth factor-1 (IGF-1) in hippocampus following denervation. Surgical denervation led to a significant increase in IGF-1 expression in vivo. We also report that IGF-1 treatment on NSCs in vitro led to a marked acceleration of Brn-4 expression and cell differentiation down neuronal pathways. The promotion effects were blocked by PI3K-specific inhibitor (LY294002), but not MAPK inhibitor (PD98059); levels of phospho-Akt were increased by IGF-1 treatment. In addition, inhibition of IGF-1 receptor (AG1024) and mTOR (rapamycin) both attenuated the increased expression of Brn-4 induced by IGF-1. Together, the results demonstrated that upregulation of IGF-1 induced by hippocampal denervation injury leads to activation of the PI3K/Akt signaling pathway, which in turn gives rise to upregulation of the Brn-4 and subsequent stem cell differentiation down neuronal pathways. PMID:25474202

IGF-1 protects against Aβ25-35-induced neuronal cell death via inhibition of PUMA expression and Bax activation.

PubMed

Hou, Xunyao; Jin, Yan; Chen, Jian; Hong, Yan; Luo, Dingzhen; Yin, Qingqing; Liu, Xueping

2017-01-10

Amyloid-β-peptide (Aβ) is considered to be the toxic species in AD and causes cell death in the affected areas of patient's brain. Insulin-like growth factor 1 (IGF-1) has been reported to attenuate Aβ toxicity in neuronal cells. However, the molecular mechanisms involved in the neuroprotective function of IGF-1 remain largely unknown. In the present study, we for the first time demonstrated that IGF-1 protects against Aβ-induced neurotoxicity via inhibition of PUMA expression and Bax activation. We found that IGF-1 could activate Akt, which in turn inhibited Aβ-induced FOXO3a nuclear translocation and thus decreased the binding ability of FOXO3a to PUMA promoter, leading to decreased PUMA expression. In addition, IGF-1 inhibited the translocation of Bax to the mitochondria induced by Aβ. Notably, addition of wortmannin, a specific inhibitor of PI3K, significantly abolished the neuroprotective effect of IGF-1, suggesting that IGF-1 exerts its anti-apoptotic effect depend on PI3K activity. Our findings may provide new insights into molecular mechanisms mediated by IGF-1 in cell survival against Aβ-induced apoptosis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

mRNA expression of CDH3, IGF2BP3, and BIRC5 in biliary brush cytology specimens is a useful adjunctive tool of cytology for the diagnosis of malignant biliary stricture

PubMed Central

Kim, Tae Ho; Chang, Jae Hyuck; Lee, Hee Jin; Kim, Jean A; Lim, Yeon Soo; Kim, Chang Whan; Han, Sok Won

2016-01-01

Abstract Although advances have been made in diagnostic tools, the distinction between malignant and benign biliary strictures still remains challenging. Intraductal brush cytology is a convenient and safe method that is used for the diagnosis of biliary stricture, but, low sensitivity limits its usefulness. This study aimed to demonstrate the usefulness of mRNA expression levels of target genes in brush cytology specimens combined with cytology for the diagnosis of malignant biliary stricture. Immunohistochemistry for cadherin 3 (CDH3), p53, insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3), homeobox B7 (HOXB7), and baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5) was performed in 4 benign and 4 malignant bile duct tissues. Through endoscopic or interventional radiologic procedures, brush cytology specimens were prospectively obtained in 21 and 35 paitents with biliary strictures. In the brush cytology specimens, the mRNA expressions levels of 5 genes were determined by real-time polymerase chain reaction. Immunohistochemistry for CDH3, p53, IGF2BP3, HOXB7, and BIRC5 all showed positive staining in malignant tissues in contrast to benign tissues, which were negative. In the brush cytology specimens, the mRNA expression levels of CDH3, IGF2BP3, HOXB7, and BIRC5 were significantly higher in cases of malignant biliary stricture compared with cases of benign stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.001). The receiver-operating characteristic curves of these 4 mRNAs demonstrated that mRNA expression levels are useful for the prediction of malignant biliary stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.002). The sensitivity and specificity, respectively, for malignant biliary stricture were 57.1% and 100% for cytology, 57.1% and 64.3% for CDH3, 76.2% and 100% for IGF2BP3, 71.4% and 57.1% for HOXB7, and 76.2% and 64.3% for BIRC5. When cytology was combined with the mRNA levels of CDH3, IGF2BP3, or BIRC5, the

Carcinoma of the colon and rectum with deregulation of insulin-like growth factor 2 signaling: clinical and molecular implications.

PubMed

Belharazem, Djeda; Magdeburg, Julia; Berton, Ann-Kristin; Beissbarth, Li; Sauer, Christian; Sticht, Carsten; Marx, Alexander; Hofheinz, Ralf; Post, Stefan; Kienle, Peter; Ströbel, Philipp

2016-10-01

Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) is an early event in the development of colorectal cancer (CRC). Whether LOI of IGF2 denotes a molecular or clinical cancer subgroup is currently unknown. Tumor biopsies and paired normal mucosa from 399 patients with extensive clinical annotations were analyzed for LOI and IGF2 expression. LOI status in 140 informative cases was correlated with clinicopathologic parameters and outcome. LOI was frequent in normal mucosa and tumors and occurred throughout the large intestine. LOI was unrelated to microsatellite instability, KRAS mutation status, stage, and survival. However, CRC with LOI showed increased IGF2 protein levels and activation of AKT1. Gene expression analysis of tumors with and without LOI and knockdown of IGF2 in cell lines revealed that IGF2 induced distinct sets of activated and repressed genes, including Wnt5a, CEACAM6, IGF2BP3, KPN2A, BRCA2, and CDK1. Inhibition of AKT1 in IGF2-stimulated cells showed that the downstream effects of IGF2 on cell proliferation and gene expression were strictly AKT1-dependent. LOI of IGF2 is a frequent and early event in CRC that occurs both in the adenomatous polyposis coli (APC) gene-mutated and serrated route of carcinogenesis. LOI leads to overexpression of IGF2, activates IGF1R and AKT1, and is a powerful driver of cell proliferation. Moreover, our results suggest that IGF2 via AKT1 also contributes to non-canonical wnt signaling. Although LOI had no significant impact on major clinical parameters and outcome, its potential as a target for preventive and therapeutic interventions merits further investigation.

Takifugu rubripes cation independent mannose 6-phosphate receptor: Cloning, expression and functional characterization of the IGF-II binding domain.

PubMed

A, Ajith Kumar; Nadimpalli, Siva Kumar

2018-07-01

Mannose 6-phosphate/IGF-II receptor mediated lysosomal clearance of insulin-like growth factor-II is significantly associated with the evolution of placental mammals. The protein is also referred to as the IGF-II receptor. Earlier studies suggested relatively low binding affinity between the receptor and ligand in prototherian and metatherian mammals. In the present study, we cloned the IGF-II binding domain of the early vertebrate fugu fish and expressed it in bacteria. A 72000Da truncated receptor containing the IGF-II binding domain was obtained. Analysis of this protein (covering domains 11-13 of the CIMPR) for its affinity to fish and human IGF-II by ligand blot assays and ELISA showed that the expressed receptor can specifically bind to both fish and human IGF-II. Additionally, a peptide-specific antibody raised against the region of the IGF-II binding domain also was able to recognize the IGF-II binding regions of mammalian and non-mammalian cation independent MPR protein. These interactions were further characterized by Surface Plasma resonance support that the receptor binds to fish IGF-II, with a dissociation constant of 548nM. Preliminary analysis suggests that the binding mechanism as well as the affinity of the fish and human receptor for IGF-II may have varied according to different evolutionary pressures. Copyright © 2018. Published by Elsevier B.V.

Positive feedback of NR2B-containing NMDA receptor activity is the initial step toward visual imprinting: a model for juvenile learning.

PubMed

Nakamori, Tomoharu; Sato, Katsushige; Kinoshita, Masae; Kanamatsu, Tomoyuki; Sakagami, Hiroyuki; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2015-01-01

Imprinting in chicks is a good model for elucidating the processes underlying neural plasticity changes during juvenile learning. We recently reported that neural activation of a telencephalic region, the core region of the hyperpallium densocellulare (HDCo), was critical for success of visual imprinting, and that N-Methyl-D-aspartic (NMDA) receptors containing the NR2B subunit (NR2B/NR1) in this region were essential for imprinting. Using electrophysiological and multiple-site optical imaging techniques with acute brain slices, we found that long-term potentiation (LTP) and enhancement of NR2B/NR1 currents in HDCo neurons were induced in imprinted chicks. Enhancement of NR2B/NR1 currents as well as an increase in surface NR2B expression occurred even following a brief training that was too weak to induce LTP or imprinting behavior. This means that NR2B/NR1 activation is the initial step of learning, well before the activation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors which induces LTP. We also showed that knockdown of NR2B/NR1 inhibited imprinting, and inversely, increasing the surface NR2B expression by treatment with a casein kinase 2 inhibitor successfully reduced training time required for imprinting. These results suggest that imprinting stimuli activate post-synaptic NR2B/NR1 in HDCo cells, increase NR2B/NR1 signaling through up-regulation of its expression, and induce LTP and memory acquisition. The study investigated the neural mechanism underlying juvenile learning. In the initial stage of chick imprinting, NMDA receptors containing the NMDA receptor subunit 2B (NR2B) are activated, surface expression of NR2B/NR1 (NMDA receptor subunit 1) is up-regulated, and consequently long-term potentiation is induced in the telencephalic neurons. We suggest that the positive feedback in the NR2B/NR1 activation is a unique process of juvenile learning, exhibiting rapid memory acquisition. © 2014 International Society for Neurochemistry.

E-Peptides Control Bioavailability of IGF-1

PubMed Central

Piszczek, Agnieszka; Perlas, Emarald; Winn, Nadine; Nastasi, Tommaso; Rosenthal, Nadia

2012-01-01

Insulin-like growth factor 1 (IGF-1) is a potent cytoprotective growth factor that has attracted considerable attention as a promising therapeutic agent. Transgenic over-expression of IGF-1 propeptides facilitates protection and repair in a broad range of tissues, although transgenic mice over-expressing IGF-1 propeptides display little or no increase in IGF-1 serum levels, even with high levels of transgene expression. IGF-1 propeptides are encoded by multiple alternatively spliced transcripts including C-terminal extension (E) peptides, which are highly positively charged. In the present study, we use decellularized mouse tissue to show that the E-peptides facilitate in vitro binding of murine IGF-1 to the extracellular matrix (ECM) with varying affinities. This property is independent of IGF-1, since proteins consisting of the E-peptides fused to relaxin, a related member of the insulin superfamily, bound equally avidly to decellularized ECM. Thus, the E-peptides control IGF-1 bioavailability by preventing systemic circulation, offering a potentially powerful way to tether IGF-1 and other therapeutic proteins to the site of synthesis and/or administration. PMID:23251442

Mature IGF-I excels in promoting functional muscle recovery from disuse atrophy compared with pro-IGF-IA.

PubMed

Park, Soohyun; Brisson, Becky K; Liu, Min; Spinazzola, Janelle M; Barton, Elisabeth R

2014-04-01

Prolonged disuse of skeletal muscle results in atrophy, and once physical activity is resumed, there is increased susceptibility to injury. Insulin-like growth factor-I (IGF-I) is considered a potential therapeutic target to attenuate atrophy during unloading and to enhance rehabilitation upon reloading of skeletal muscles, due to its multipronged actions on satellite cell proliferation, differentiation, and survival, as well as its actions on muscle fibers to boost protein synthesis and inhibit protein degradation. However, the form of IGF-I delivered may alter the success of treatment. Using the hindlimb suspension model of disuse atrophy, we compared the efficacy of two IGF-I forms in protection against atrophy and enhancement of recovery: mature IGF-I (IGF-IS) lacking the COOH-terminal extension, called the E-peptide, and IGF-IA, which is the predominant form retaining the E-peptide. Self-complementary adeno-associated virus harboring the murine Igf1 cDNA constructs were delivered to hindlimbs of adult female C57BL6 mice 3 days prior to hindlimb suspension. Hindlimb muscles were unloaded for 7 days and then reloaded for 3, 7, and 14 days. Loss of muscle mass following suspension was not prevented by either IGF-I construct. However, IGF-IS expression maintained soleus muscle force production. Further, IGF-IS treatment caused rapid recovery of muscle fiber morphology during reloading and maintained muscle strength. Analysis of gene expression revealed that IGF-IS expression accelerated the downregulation of atrophy-related genes compared with untreated or IGF-IA-treated samples. We conclude that mature-IGF-I may be a better option than pro-IGF-IA to promote skeletal muscle recovery following disuse atrophy.

Mature IGF-I excels in promoting functional muscle recovery from disuse atrophy compared with pro-IGF-IA

PubMed Central

Park, SooHyun; Brisson, Becky K.; Liu, Min; Spinazzola, Janelle M.

2013-01-01

Prolonged disuse of skeletal muscle results in atrophy, and once physical activity is resumed, there is increased susceptibility to injury. Insulin-like growth factor-I (IGF-I) is considered a potential therapeutic target to attenuate atrophy during unloading and to enhance rehabilitation upon reloading of skeletal muscles, due to its multipronged actions on satellite cell proliferation, differentiation, and survival, as well as its actions on muscle fibers to boost protein synthesis and inhibit protein degradation. However, the form of IGF-I delivered may alter the success of treatment. Using the hindlimb suspension model of disuse atrophy, we compared the efficacy of two IGF-I forms in protection against atrophy and enhancement of recovery: mature IGF-I (IGF-IS) lacking the COOH-terminal extension, called the E-peptide, and IGF-IA, which is the predominant form retaining the E-peptide. Self-complementary adeno-associated virus harboring the murine Igf1 cDNA constructs were delivered to hindlimbs of adult female C57BL6 mice 3 days prior to hindlimb suspension. Hindlimb muscles were unloaded for 7 days and then reloaded for 3, 7, and 14 days. Loss of muscle mass following suspension was not prevented by either IGF-I construct. However, IGF-IS expression maintained soleus muscle force production. Further, IGF-IS treatment caused rapid recovery of muscle fiber morphology during reloading and maintained muscle strength. Analysis of gene expression revealed that IGF-IS expression accelerated the downregulation of atrophy-related genes compared with untreated or IGF-IA-treated samples. We conclude that mature-IGF-I may be a better option than pro-IGF-IA to promote skeletal muscle recovery following disuse atrophy. PMID:24371018

c-myb stimulates cell growth by regulation of insulin-like growth factor (IGF) and IGF-binding protein-3 in K562 leukemia cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Min-Sun; Kim, Sun-Young; Arunachalam, Sankarganesh

2009-07-17

c-myb plays an important role in the regulation of cell growth and differentiation, and is highly expressed in immature hematopoietic cells. The human chronic myelogenous leukemia cell K562, highly expresses IGF-I, IGF-II, IGF-IR, and IGF-induced cellular proliferation is mediated by IGF-IR. To characterize the impact of c-myb on the IGF-IGFBP-3 axis in leukemia cells, we overexpressed c-myb using an adenovirus gene transfer system in K562 cells. The overexpression of c-myb induced cell proliferation, compared to control, and c-myb induced cell growth was inhibited by anti-IGF-IR antibodies. c-myb overexpression resulted in a significant increase in the expression of IGF-I, IGF-II, andmore » IGF-IR, and a decrease in IGFBP-3 expression. By contrast, disruption of c-myb function by DN-myb overexpression resulted in significant reduction of IGF-I, IGF-II, IGF-IR, and elevation of IGFBP-3 expression. In addition, exogenous IGFBP-3 inhibited the proliferation of K562 cells, and c-myb induced cell growth was blocked by IGFBP-3 overexpression in a dose-dependent manner. The growth-promoting effects of c-myb were mediated through two major intracellular signaling pathways, Akt and Erk. Activation of Akt and Erk by c-myb was completely blocked by IGF-IR and IGFBP-3 antibodies. These findings suggest that c-myb stimulates cell growth, in part, by regulating expression of the components of IGF-IGFBP axis in K562 cells. In addition, disruption of c-myb function by DN-myb may provide a useful strategy for treatment of leukemia.« less

Expression of insulin-like growth factor-2 receptors on EL4 lymphoma cells overexpressing growth hormone.

PubMed

Farmer, John T; Weigent, Douglas A

2007-01-01

In the present study, we report the upregulation of functional IGF-2Rs in cells overexpressing growth hormone (GH). EL4 lymphoma cells stably transfected with an rGH cDNA overexpression vector (GHo) exhibited an increase in the binding of (125)I-IGF-2 with no change in the binding affinity compared to vector alone controls. An increase in the expression of the insulin-like growth factor-2 receptor (IGF-2R) in cells overexpressing GH was confirmed by Western blot analysis and IGF-2R promoter luciferase assays. EL4 cells produce insulin-like growth factor-2 (IGF-2) as detected by the reverse transcription-polymerase chain reaction (RT-PCR); however, no IGF-2 protein was detected by Western analysis. The increase in the expression of the IGF-2R resulted in greater levels of IGF-2 uptake in GHo cells compared to vector alone controls. The data suggest that one of the consequences of the overexpression of GH is an increase in the expression of the IGF-2R.

MicroRNA-214 Reduces Insulin-like Growth Factor-1 (IGF-1) Receptor Expression and Downstream mTORC1 Signaling in Renal Carcinoma Cells*

PubMed Central

Das, Falguni; Dey, Nirmalya; Bera, Amit; Kasinath, Balakuntalam S.; Ghosh-Choudhury, Nandini; Choudhury, Goutam Ghosh

2016-01-01

Elevated IGF-1/insulin-like growth factor-1 receptor (IGF-1R) autocrine/paracrine signaling in patients with renal cell carcinoma is associated with poor prognosis of the disease independent of their von Hippel-Lindau (VHL) status. Increased expression of IGF-1R in renal cancer cells correlates with their potency of tumor development and progression. The mechanism by which expression of IGF-1R is increased in renal carcinoma is not known. We report that VHL-deficient and VHL-positive renal cancer cells possess significantly decreased levels of mature, pre-, and pri-miR-214 than normal proximal tubular epithelial cells. We identified an miR-214 recognition element in the 3′UTR of IGF-1R mRNA and confirmed its responsiveness to miR-214. Overexpression of miR-214 decreased the IGF-1R protein levels, resulting in the inhibition of Akt kinase activity in both types of renal cancer cells. IGF-1 provoked phosphorylation and inactivation of PRAS40 in an Akt-dependent manner, leading to the activation of mTORC1 signal transduction to increase phosphorylation of S6 kinase and 4EBP-1. Phosphorylation-deficient mutants of PRAS40 and 4EBP-1 significantly inhibited IGF-1R-driven proliferation of renal cancer cells. Expression of miR-214 suppressed IGF-1R-induced phosphorylation of PRAS40, S6 kinase, and 4EBP-1, indicating inhibition of mTORC1 activity. Finally, miR-214 significantly blocked IGF-1R-forced renal cancer cell proliferation, which was reversed by expression of 3′UTR-less IGF-1R and constitutively active mTORC1. Together, our results identify a reciprocal regulation of IGF-1R levels and miR-214 expression in renal cancer cells independent of VHL status. Our data provide evidence for a novel mechanism for IGF-1R-driven renal cancer cell proliferation involving miR-214 and mTORC1. PMID:27226530

The impact of IGF-1R expression on the outcomes of patients with breast cancer: a meta-analysis

PubMed Central

Yan, Shunchao; Jiao, Xin; Li, Kai; Li, Wusheng; Zou, Huawei

2015-01-01

IGF-1R positivity in Her-2-positive or ER (estrogen receptor)-negative breast cancer was not found to be a significant prognostic indicator. Conclusion The results of this meta-analysis suggest that IGF-1R expression has different prognostic values for patients with breast cancers of different molecular subtypes. It was a favorable prognostic indicator in unselected breast cancers and hormone-receptor-positive cancers, but indicated poor survival in triple-negative breast cancers. PMID:25674003

Stocking density affects the growth performance and metabolism of Amur sturgeon by regulating expression of genes in the GH/IGF axis

NASA Astrophysics Data System (ADS)

Ren, Yuanyuan; Wen, Haishen; Li, Yun; Li, Jifang

2017-07-01

The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three different stocking densities (low stocking density, LSD: 5.5 kg/m3; medium stocking density, MSD: 8.0 kg/m3; and high stocking density, HSD: 11.0 kg/m3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower final body weight and specific growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2 (IGF-2), while the concentrations of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) decreased in the HSD group. The full-length cDNAs of GH and IGF-2 genes (995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor (GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively affects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.

IGF-II Promotes Stemness of Neural Restricted Precursors

PubMed Central

Ziegler, Amber N.; Schneider, Joel S.; Qin, Mei; Tyler, William A.; Pintar, John E.; Fraidenraich, Diego; Wood, Teresa L.; Levison, Steven W.

2016-01-01

Insulin-like growth factor (IGF)-I and IGF-II regulate brain development and growth through the IGF type 1 receptor (IGF-1R). Less appreciated is that IGF-II, but not IGF-I, activates a splice variant of the insulin receptor (IR) known as IR-A. We hypothesized that IGF-II exerts distinct effects from IGF-I on neural stem/progenitor cells (NSPs) via its interaction with IR-A. Immunofluorescence revealed high IGF-II in the medial region of the subventricular zone (SVZ) comprising the neural stem cell niche, with IGF-II mRNA predominant in the adjacent choroid plexus. The IGF-1R and the IR isoforms were differentially expressed with IR-A predominant in the medial SVZ, whereas the IGF-1R was more abundant laterally. Similarly, IR-A was more highly expressed by NSPs, whereas the IGF-1R was more highly expressed by lineage restricted cells. In vitro, IGF-II was more potent in promoting NSP expansion than either IGF-I or standard growth medium. Limiting dilution and differentiation assays revealed that IGF-II was superior to IGF-I in promoting stemness. In vivo, NSPs propagated in IGF-II migrated to and took up residence in periventricular niches while IGF-I-treated NSPs predominantly colonized white matter. Knockdown of IR or IGF-1R using shRNAs supported the conclusion that the IGF-1R promotes progenitor proliferation, whereas the IR is important for self-renewal. Q-PCR revealed that IGF-II increased Oct4, Sox1, and FABP7 mRNA levels in NSPs. Our data support the conclusion that IGF-II promotes the self-renewal of neural stem/progenitors via the IR. By contrast, IGF-1R functions as a mitogenic receptor to increase precursor abundance. PMID:22593020

HSF1 phosphorylation by ERK/GSK3 suppresses RNF126 to sustain IGF-IIR expression for hypertension-induced cardiomyocyte hypertrophy.

PubMed

Huang, Chih-Yang; Lee, Fa-Lun; Peng, Shu-Fen; Lin, Kuan-Ho; Chen, Ray-Jade; Ho, Tsung-Jung; Tsai, Fu-Jen; Padma, Vijaya V; Kuo, Wei-Wen; Huang, Chih-Yang

2018-02-01

Hypertension-induced cardiac hypertrophy and apoptosis are major characteristics of early-stage heart failure (HF). Inhibition of extracellular signal-regulated kinases (ERK) efficaciously suppressed angiotensin II (ANG II)-induced cardiomyocyte hypertrophy and apoptosis by blocking insulin-like growth factor II receptor (IGF-IIR) signaling. However, the detailed mechanism by which ANG II induces ERK-mediated IGF-IIR signaling remains elusive. Here, we found that ANG II activated ERK to upregulate IGF-IIR expression via the angiotensin II type I receptor (AT 1 R). ERK activation subsequently phosphorylates HSF1 at serine 307, leading to a secondary phosphorylation by glycogen synthase kinase III (GSK3) at serine 303. Moreover, we found that ANG II mediated ERK/GSK3-induced IGF-IIR protein stability by downregulating the E3 ubiquitin ligase of IGF-IIR RING finger protein CXXVI (RNF126). The expression of RNF126 decreased following ANG II-induced HSF1 S303 phosphorylation, resulting in IGF-IIR protein stability and increased cardiomyocyte injury. Inhibition of GSK3 significantly alleviated ANG II-induced cardiac hypertrophy in vivo and in vitro. Taken together, these results suggest that HSF1 phosphorylation stabilizes IGF-IIR protein stability by downregulating RNF126 during cardiac hypertrophy. ANG II activates ERK/GSK3 to phosphorylate HSF1, resulting in RNF126 degradation, which stabilizes IGF-IIR protein expression and eventually results in cardiac hypertrophy. HSF1 could be a valuable therapeutic target for cardiac diseases among hypertensive patients. © 2017 Wiley Periodicals, Inc.

Human GH Receptor-IGF-1 Receptor Interaction: Implications for GH Signaling

PubMed Central

Gan, Yujun; Buckels, Ashiya; Liu, Ying; Zhang, Yue; Paterson, Andrew J.; Jiang, Jing; Zinn, Kurt R.

2014-01-01

GH signaling yields multiple anabolic and metabolic effects. GH binds the transmembrane GH receptor (GHR) to activate the intracellular GHR-associated tyrosine kinase, Janus kinase 2 (JAK2), and downstream signals, including signal transducer and activator of transcription 5 (STAT5) activation and IGF-1 gene expression. Some GH effects are partly mediated by GH-induced IGF-1 via IGF-1 receptor (IGF-1R), a tyrosine kinase receptor. We previously demonstrated in non-human cells that GH causes formation of a GHR-JAK2-IGF-1R complex and that presence of IGF-1R (even without IGF-1 binding) augments proximal GH signaling. In this study, we use human LNCaP prostate cancer cells as a model system to further study the IGF-1R's role in GH signaling. GH promoted JAK2 and GHR tyrosine phosphorylation and STAT5 activation in LNCaP cells. By coimmunoprecipitation and a new split luciferase complementation assay, we find that GH augments GHR/IGF-1R complex formation, which is inhibited by a Fab of an antagonistic anti-GHR monoclonal antibody. Short hairpin RNA-mediated IGF-1R silencing in LNCaP cells reduced GH-induced GHR, JAK2, and STAT5 phosphorylation. Similarly, a soluble IGF-1R extracellular domain fragment (sol IGF-1R) interacts with GHR in response to GH and blunts GH signaling. Sol IGF-1R also markedly inhibits GH-induced IGF-1 gene expression in both LNCaP cells and mouse primary osteoblast cells. On the basis of these and other findings, we propose a model in which IGF-1R augments GH signaling by allowing a putative IGF-1R-associated molecule that regulates GH signaling to access the activated GHR/JAK2 complex and envision sol IGF-1R as a dominant-negative inhibitor of this IGF-1R-mediated augmentation. Physiological implications of this new model are discussed. PMID:25211187

The proto-oncogene product c-Crk associates with insulin receptor substrate-1 and 4PS. Modulation by insulin growth factor-I (IGF) and enhanced IGF-I signaling.

PubMed

Beitner-Johnson, D; Blakesley, V A; Shen-Orr, Z; Jimenez, M; Stannard, B; Wang, L M; Pierce, J; LeRoith, D

1996-04-19

The Crk proto-oncogene product is an SH2 and SH3 domain-containing adaptor protein which we have previously shown to become rapidly tyrosine phosphorylated in response to stimulation with insulin-like growth factor I (IGF-I) in NIH-3T3 cells. In order to further characterize the role of Crk in the IGF-I signaling pathway, NIH-3T3 and 293 cells were stably transfected with an expression vector containing the Crk cDNA. The various resultant 3T3-Crk clones expressed Crk at approximately 2-15-fold higher levels than parental 3T3 cells. In 3T3-Crk cells, Crk immunoreactivity was detected in insulin receptor substrate-1 (IRS-1) immunoprecipitates. Stimulation with IGF-I resulted in a dissociation of Crk protein from IRS-1. In contrast, the association of the related adaptor protein Grb2 with IRS-1 was enhanced by IGF-I stimulation. Similar results were obtained in stably transfected 293-Crk cells, which express both IRS-1 and the IRS-1-related signaling protein 4PS. In these cells, IRS-1 and 4PS both associated with Crk, and this association was also decreased by IGF-I treatment, whereas the association of Grb2 with IRS-1 and 4PS was enhanced by IGF-I. Overexpression of Crk also enhanced IGF-I-induced mitogenesis of NIH-3T3 cells, as measured by [3H]thymidine incorporation. The levels of IGF-I-induced mitogenesis were proportional to the level of Crk expression. These results suggest that Crk is a positive effector of IGF-I signaling, and may mediate its effects via interaction with IRS-1 and/or 4PS.

IGF1R blockade with ganitumab results in systemic effects on the GH–IGF axis in mice

PubMed Central

Moody, Gordon; Beltran, Pedro J; Mitchell, Petia; Cajulis, Elaina; Chung, Young-Ah; Hwang, David; Kendall, Richard; Radinsky, Robert; Cohen, Pinchas; Calzone, Frank J

2014-01-01

Ganitumab is a fully human MAB to the human type 1 IGF receptor (IGF1R). Binding assays showed that ganitumab recognized murine IGF1R with sub-nanomolar affinity (KD=0.22 nM) and inhibited the interaction of murine IGF1R with IGF1 and IGF2. Ganitumab inhibited IGF1-induced activation of IGF1R in murine lungs and CT26 murine colon carcinoma cells and tumors. Addition of ganitumab to 5-fluorouracil resulted in enhanced inhibition of tumor growth in the CT26 model. Pharmacological intervention with ganitumab in naïve nude mice resulted in a number of physiological changes described previously in animals with targeted deletions of Igf1 and Igf1r, including inhibition of weight gain, reduced glucose tolerance and significant increase in serum levels of GH, IGF1 and IGFBP3. Flow cytometric analysis identified GR1/CD11b-positive cells as the highest IGF1R-expressing cells in murine peripheral blood. Administration of ganitumab led to a dose-dependent, reversible decrease in the number of peripheral neutrophils with no effect on erythrocytes or platelets. These findings indicate that acute IGF availability for its receptor plays a critical role in physiological growth, glucose metabolism and neutrophil physiology and support the presence of a pituitary IGF1R-driven negative feedback loop that tightly regulates serum IGF1 levels through Gh signaling. PMID:24492468

Insulin-like growth factor (IGF) binding protein from human decidua inhibits the binding and biological action of IGF-I in cultured choriocarcinoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritvos, O.; Ranta, T.; Jalkanen, J.

1988-05-01

The placenta expresses genes for insulin-like growth factors (IGFs) and possesses IGF-receptors, suggesting that placental growth is regulated by IGFs in an autocrine manner. We have previously shown that human decidua, but not placenta, synthesizes and secretes a 34 K IGF-binding protein (34 K IGF-BP) called placental protein 12. We now used human choriocarcinoma JEG-3 cell monolayer cultures and recombinant (Thr59)IGF-I as a model to study whether the decidual 34 K IGF-BP is able to modulate the receptor binding and biological activity of IGFs in trophoblasts. JEG-3 cells, which possess type I IGF receptors, were unable to produce IGF-BPs. Purifiedmore » 34 K IGF-BP specifically bound (125I)iodo-(Thr59)IGF-I. Multiplication-stimulating activity had 2.5% the potency of (Thr59)IGF-I, and insulin had no effect on the binding of (125I) iodo-(Thr59)IGF-I. 34 K IGF-BP inhibited the binding of (125I) iodo-(Thr59)IGF-I to JEG-3 monolayers in a concentration-dependent manner by forming with the tracer a soluble complex that could not bind to the cell surface as demonstrated by competitive binding and cross-linking experiments. After incubating the cell monolayers with (125I)iodo-(Thr59)IGF-I in the presence of purified binding protein, followed by cross-linking, no affinity labeled bands were seen on autoradiography. In contrast, an intensely labeled band at 40 K was detected when the incubation medium was analyzed, suggesting that (Thr59)IGF-I and 34 K IGF-BP formed a complex in a 1:1 molar ratio. Also, 34 K IGF-BP inhibited both basal and IGF-I-stimulated uptake of alpha-(3H)aminoisobutyric acid in JEG-3 cells. RNA analysis revealed that IGF-II is expressed in JEG-3 cells.« less

Regulation of surface expression of TRPV2 channels in the retinal pigment epithelium.

PubMed

Reichhart, Nadine; Keckeis, Susanne; Fried, Frederik; Fels, Gabriele; Strauss, Olaf

2015-06-01

The retinal pigment epithelium (RPE) interacts closely with the photoreceptors in fulfilling tasks of visual function. Since an understanding of the RPE function is essential for understanding the patho-mechanisms involved in vision loss, we explored the regulation of the vanilloid receptor subtype transient receptor potential TRPV2 channels that trigger insulin-like growth factor-1 (IGF-1)-induced vascular endothelial growth factor A (VEGF-A) secretion. Immunohistochemistry was used to assess TRPV2 expression in retinal cross-sections or ARPE-19 cells, and surface expression of TRPV2 was quantified using confocal microscopy. Membrane currents of ARPE-19 cells were recorded using a whole-cell configuration of the patch-clamp technique. TRPV2 expression was detected in the RPE of the mouse retina as well as in ARPE-19 cells. Increasing the temperature to 45 °C activated membrane conductance sensitive to SKF-96365 and ruthenium red in 60 % of cells. Preincubation with either cannabidiol (CBD) or IGF-1 led to a three- or fourfold increase in current density, respectively, in all cells, which was blocked by SKF-96365. In contrast to IGF-1, CBD stimulation of membrane conductance was further increased by heat. TRPV2 surface expression was increased by both IGF-1 and CBD, with the increase by CBD twice as large as that by IGF-1. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 abolished the effects on membrane conductance and surface expression. Both CBD and IGF-1 enhance TRPV2 channel activity by specific proportions of both channel activation and PI 3-kinase-dependent surface expression: IGF-1 predominantly increases ion channel activity, whereas CBD is more active in increasing TRPV2 surface expression. Thus, differential regulation of TRPV2 surface expression is an important mechanism for modulating the responsiveness of the RPE to growth factors.

Can insulin-like growth factor 1 (IGF-1), IGF-1 receptor connective tissue growth factor and Ki-67 labelling index have a prognostic role in pulmonary carcinoids?

PubMed

Kanakis, Georgios A; Grimelius, Lars; Papaioannou, Dimitrios; Kaltsas, Gregory; Tsolakis, Apostolos V

2018-04-27

Altered expression of Insulin-like Growth Factor-1 (IGF-1), its receptor (IGF-1R), Connective Tissue Growth Factor (CTGF) and Hypoxia Inducible Factor-1 (HIF-1), has been implicated in tumorigenesis. So far, these factors have not been studied systematically in Pulmonary Carcinoids (PCs). To examine IGF-1, IGF-1R, CTGF and HIF-1 expression in PCs, and assess their prognostic value over established factors. Retrospective study of 121 PCs (104 Typical and 17 Atypical). The expression of growth factors was studied immunohistochemically and tumors were considered positive if immunoreactivity appeared in >50% of cells. All studied parameters were expressed in the majority of tumors (IGF-1, IGF-1R, CTGF and HIF-1, in 78.5%, 67%, 72% and 78%, respectively). Their expression tended to be more frequent in TCs and in tumors with Ki-67≤2% (significant only for HIF-1; 82 vs. 53%; p=0.023 and 83 vs. 63%; p=0.025 respectively). CTGF was the only factor correlated with more extensive disease (larger size; presence of lymph node and distant metastases). According to logistic regression analysis, only advanced age, Ki-67≥3.4% and lymph node involvement could predict the development of distant metastases. IGF-1, IGF-1R, CTGF and HIF-1 are avidly expressed in PCs; however, their presence did not appear to be of statistically significant value over established prognostic factors.

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker

PubMed Central

Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E.; Whitley, Guy; Johnsen, Guro M.; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C.; Müller, Dominik N.; Staff, Anne Cathrine

2017-01-01

Background: Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. Methods: We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. Results: We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5, with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker.

PubMed

Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E; Whitley, Guy; Johnsen, Guro M; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C; Müller, Dominik N; Staff, Anne Cathrine; Hurst, Laurence D; Dechend, Ralf; Izsvák, Zsuzsanna

2017-11-07

Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5 , with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5 high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in

The imprinted gene Magel2 regulates normal circadian output.

PubMed

Kozlov, Serguei V; Bogenpohl, James W; Howell, Maureen P; Wevrick, Rachel; Panda, Satchin; Hogenesch, John B; Muglia, Louis J; Van Gelder, Russell N; Herzog, Erik D; Stewart, Colin L

2007-10-01

Mammalian circadian rhythms of activity are generated within the suprachiasmatic nucleus (SCN). Transcripts from the imprinted, paternally expressed Magel2 gene, which maps to the chromosomal region associated with Prader-Willi Syndrome (PWS), are highly enriched in the SCN. The Magel2 message is circadianly expressed and peaks during the subjective day. Mice deficient in Magel2 expression entrain to light cycles and express normal running-wheel rhythms, but with markedly reduced amplitude of activity and increased daytime activity. These changes are associated with reductions in food intake and male fertility. Orexin levels and orexin-positive neurons in the lateral hypothalamus are substantially reduced, suggesting that some of the consequences of Magel2 loss are mediated through changes in orexin signaling. The robust rhythmicity of Magel2 expression in the SCN and the altered behavioral rhythmicity of null mice reveal Magel2 to be a clock-controlled circadian output gene whose disruption results in some of the phenotypes characteristic of PWS.

R1507, an Anti-Insulin-Like Growth Factor-1 Receptor (IGF-1R) Antibody, and EWS/FLI-1 siRNA in Ewing's Sarcoma: Convergence at the IGF/IGFR/Akt Axis

PubMed Central

Rodon, Jordi; Sun, Michael; Kuenkele, Klaus-Peter; Parsons, Henrique A.; Trent, Jonathan C.; Kurzrock, Razelle

2011-01-01

A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R) antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si) RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71) was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays). TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney) cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt. PMID:22022506

Nandrolone and stanozolol upregulate aromatase expression and further increase IGF-I-dependent effects on MCF-7 breast cancer cell proliferation.

PubMed

Sirianni, Rosa; Capparelli, Claudia; Chimento, Adele; Panza, Salvatore; Catalano, Stefania; Lanzino, Marilena; Pezzi, Vincenzo; Andò, Sebastiano

2012-11-05

Several doping agents, such as anabolic androgenic steroids (AAS) and peptide hormones like insulin-like growth factor-I (IGF-I), are employed without considering the potential deleterious effects that they can cause. In addition, androgens are used in postmenopausal women as replacement therapy. However, there are no clear guidelines regarding the optimal therapeutic doses of androgens or long-term safety data. In this study we aimed to determine if two commonly used AAS, nandrolone and stanozolol, alone or in combination with IGF-I, could activate signaling involved in breast cancer cell proliferation. Using a human breast cancer cell line, MCF-7, as an experimental model we found that both nandrolone and stanozolol caused a dose-dependent induction of aromatase expression and, consequently, estradiol production. Moreover, when nandrolone and stanozolol were combined with IGF-I, higher induction in aromatase expression was observed. This increase involved phosphatidylinositol 3-kinase (PI3K)/AKT and phospholipase C (PLC)/protein kinase C (PKC), which are part of IGF-I transductional pathways. Specifically, both AAS were able to activate membrane rapid signaling involving IGF-I receptor, extracellular regulated protein kinases 1/2 (ERK1/2) and AKT, after binding to estrogen receptor (ER), as confirmed by the ability of the ER antagonist ICI182, 780 to block such activation. The estrogenic activity of nandrolone and stanozolol was further confirmed by their capacity to induce the expression of the ER-regulated gene, CCND1 encoding for the cell cycle regulator cyclin D1, which represents a key protein for the control of breast cancer cell proliferation. In fact, when nandrolone and stanozolol were combined with IGF-I, they increased cell proliferation to levels higher than those elicited by the single factors. Taken together these data clearly indicate that the use of high doses of AAS, as occurs in doping practice, may increase the risk of breast cancer. This

mRNA levels of imprinted genes in bovine in vivo oocytes, embryos and cross species comparisons in humans, mice and pigs

USDA-ARS?s Scientific Manuscript database

Twenty-six confirmed imprinted genes in the bovine were quantified in in vivo produced oocytes and embryos. Eighteen were detectable and their transcriptional abundance were categorized into five patterns: largely decreased (MEST and PLAGL1); first decreased and then increased (CDKN1C and IGF2R); p...

IGF-1 prevents simvastatin-induced myotoxicity in C2C12 myotubes.

PubMed

Bonifacio, Annalisa; Sanvee, Gerda M; Brecht, Karin; Kratschmar, Denise V; Odermatt, Alex; Bouitbir, Jamal; Krähenbühl, Stephan

2017-05-01

Statins are generally well tolerated, but treatment with these drugs may be associated with myopathy. The mechanisms of statin-associated myopathy are not completely understood. Statins inhibit AKT phosphorylation by an unclear mechanism, whereas insulin-like growth factor (IGF-1) activates the IGF-1/AKT signaling pathway and promotes muscle growth. The aims of the study were to investigate mechanisms of impaired AKT phosphorylation by simvastatin and to assess effects of IGF-1 on simvastatin-induced myotoxicity in C2C12 myotubes. C2C12 mouse myotubes were exposed to 10 μM simvastatin and/or 10 ng/mL IGF-1 for 18 h. Simvastatin inhibited the IGF-1/AKT signaling pathway, resulting in increased breakdown of myofibrillar proteins, impaired protein synthesis and increased apoptosis. Simvastatin inhibited AKT S473 phosphorylation, indicating reduced activity of mTORC2. In addition, simvastatin impaired stimulation of AKT T308 phosphorylation by IGF-1, indicating reduced activation of the IGF-1R/PI3K pathway by IGF-1. Nevertheless, simvastatin-induced myotoxicity could be at least partially prevented by IGF-1. The protective effects of IGF-1 were mediated by activation of the IGF-1R/AKT signaling cascade. Treatment with IGF-1 also suppressed muscle atrophy markers, restored protein synthesis and inhibited apoptosis. These results were confirmed by normalization of myotube morphology and protein content of C2C12 cells exposed to simvastatin and treated with IGF-1. In conclusion, impaired activity of AKT can be explained by reduced function of mTORC2 and of the IGF-1R/PI3K pathway. IGF-1 can prevent simvastatin-associated cytotoxicity and metabolic effects on C2C12 cells. The study gives insight into mechanisms of simvastatin-associated myotoxicity and provides potential targets for therapeutic intervention.

Expressions of IGF-1, ERK, GLUT4, IRS-1 in metabolic syndrome complicated with colorectal cancer and their associations with the clinical characteristics of CRC.

PubMed

Hu, Jianxia; Liu, Xiaoyi; Chi, Jingwei; Che, Kui; Feng, Yan; Zhao, Shihua; Wang, Zhongchao; Wang, Yangang

2018-01-01

Epidemiological data have revealed that colorectal cancer (CRC) risk is increased in patients with Metabolic syndrome. To explore the expressions of IGF-1, ERK, GLUT4, IRS-1 in MS patients with CRC and their associations with the clinical characteristics of CRC. We investigated the expressions of IGF-1, ERK, GLUT4 and IRS-1 in greater omental adipose tissues of 168 MS patients with/without CRC, 85 CRC patients without MS and 98 healthy controls by RT-PCR, and analyzed the relationships between their expressions and clinical characteristics of CRC. The expression levels of IGF-1 and ERK in MS patients with/without CRC were higher while the expression levels of GLUT4 were lower compared with CRC patients without MS and healthy controls (P< 0.01). The expression levels of IGF-1 and ERK in MS patients with CRC were higher while expression levels of GLUT4 were lower compared to MS patients without CRC (P< 0.01). Expression levels of ERK, IGF-1, GLUT4 were associated with clinical characteristics of CRC, including tumor size, distant metastasis and advanced stages (III/IV) (P< 0.05). Expressions of IGF-1, ERK and GLUT4 in greater omental adipose tissues might be useful biomarkers and predictive targets in the diagnosis of CRC.

Assessment of imprinting- and genetic variation-dependent monoallelic expression using reciprocal allele descendants between human family trios.

PubMed

Chuang, Trees-Juen; Tseng, Yu-Hsiang; Chen, Chia-Ying; Wang, Yi-Da

2017-08-01

Genomic imprinting is an important epigenetic process that silences one of the parentally-inherited alleles of a gene and thereby exhibits allelic-specific expression (ASE). Detection of human imprinting events is hampered by the infeasibility of the reciprocal mating system in humans and the removal of ASE events arising from non-imprinting factors. Here, we describe a pipeline with the pattern of reciprocal allele descendants (RADs) through genotyping and transcriptome sequencing data across independent parent-offspring trios to discriminate between varied types of ASE (e.g., imprinting, genetic variation-dependent ASE, and random monoallelic expression (RME)). We show that the vast majority of ASE events are due to sequence-dependent genetic variant, which are evolutionarily conserved and may themselves play a cis-regulatory role. Particularly, 74% of non-RAD ASE events, even though they exhibit ASE biases toward the same parentally-inherited allele across different individuals, are derived from genetic variation but not imprinting. We further show that the RME effect may affect the effectiveness of the population-based method for detecting imprinting events and our pipeline can help to distinguish between these two ASE types. Taken together, this study provides a good indicator for categorization of different types of ASE, opening up this widespread and complex mechanism for comprehensive characterization.

Secretion pathway of liver IGF-1 via JAK2/STAT3 in chick embryo under the monochromatic light.

PubMed

Wang, Tuanjie; Dong, Yulan; Wang, Zixu; Cao, Jing; Chen, Yaoxing

2016-02-01

This study reveals mechanism of monochromatic light on the IGF-1 secretion of chick embryo liver. The chick embryos were incubated and exposed to continuous red, green, blue light or a dark environment. Compared to other light-treated groups, green light increased IGF-1 and melatonin concentrations both in plasma and liver, and Mel1a, Mel1b and Mel1c receptors expressions in liver but decreased p-JAK2, p-STAT3 and ROS in liver. IGF-1 had a positive correlation with melatonin, but a negative relevance with p-JAK2 and p-STAT3. In vitro, the IGF-1 level in the hepatocyte supernatant was enhanced by melatonin with lower p-JAK2/p-STAT3 and ROS levels, which was suppressed by Mel1c antagonist but not Mel1a/Mel1b or Mel1b antagonists. AG490 (JAK/STAT inhibitor) promoted role of melatonin-Mel1c modulated IGF-1 secretion. These results suggest the antioxidant effect of melatonin mediated the green light-enhanced IGF-1 secretion of chick embryo liver through Mel1c receptor to inhibit the JAK2/STAT3 pathway.

Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Hua; Lin, Yingbo; Badin, Margherita

2011-01-14

Research highlights: {yields} SUMOylation mediates nuclear translocation of IGF-1R which activates transcription. {yields} Here we show that nuclear IGF-1R over-accumulates in tumor cells. {yields} This requires overexpression of the receptor that is a common feature in tumor cells. {yields} An increased expression of the SUMO ligase Ubc9 seems to be an involved mechanism too. -- Abstract: The insulin-like growth factor 1 receptor (IGF-1R) plays crucial roles in tumor cell growth and is overexpressed in many cancers. IGF-1R's trans-membrane kinase signaling pathways have been well characterized. Very recently, we showed that SUMOylation mediates nuclear translocation of the IGF-1R, and that nuclearmore » IGF-1R (nIGF-1R) binds to enhancer regions and activates transcription. We identified three lysine residues in the {beta}-subunit of the receptor and that mutation of these blocks nuclear translocation and gene activation. Furthermore, accumulation of nIGF-1R was proven strongly dependent on the specific SUMO-conjugating enzyme Ubc9. Here we show that nIGF-1R originates solely from the cell membrane and that phosphorylation of the core tyrosine residues of the receptor kinase is crucial for nuclear accumulation. We also compared the levels of nIGF-1R, measured as nuclear/membrane ratios, in tumor and normal cells. We found that the breast cancer cell line MCF-7 has 13-fold higher amounts of nIGF-1R than breast epithelial cells (IME) which showed only a small amount of nIGF-1R. In comparison, the total expression of IGF-1R was only 3.7- higher in MCF-7. Comparison of several other tumor and normal cell lines showed similar tumor cell over-accumulation of nIGF-1R, exceeding the total receptor expression substantially. Ectopic overexpression (>10-fold) of the receptor increased nIGF-1R in IME cells but not to that high level as in wild type MCF-7. The levels of Ubc9 were higher in all tumor cell lines, compared to the normal cells, and this probably contributes to

Phosphatidylinositol 3-Kinase (PI3K) Activity Bound to Insulin-like Growth Factor-I (IGF-I) Receptor, which Is Continuously Sustained by IGF-I Stimulation, Is Required for IGF-I-induced Cell Proliferation*

PubMed Central

Fukushima, Toshiaki; Nakamura, Yusaku; Yamanaka, Daisuke; Shibano, Takashi; Chida, Kazuhiro; Minami, Shiro; Asano, Tomoichiro; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

2012-01-01

Continuous stimulation of cells with insulin-like growth factors (IGFs) in G1 phase is a well established requirement for IGF-induced cell proliferation; however, the molecular components of this prolonged signaling pathway that is essential for cell cycle progression from G1 to S phase are unclear. IGF-I activates IGF-I receptor (IGF-IR) tyrosine kinase, followed by phosphorylation of substrates such as insulin receptor substrates (IRS) leading to binding of signaling molecules containing SH2 domains, including phosphatidylinositol 3-kinase (PI3K) to IRS and activation of the downstream signaling pathways. In this study, we found prolonged (>9 h) association of PI3K with IGF-IR induced by IGF-I stimulation. PI3K activity was present in this complex in thyrocytes and fibroblasts, although tyrosine phosphorylation of IRS was not yet evident after 9 h of IGF-I stimulation. IGF-I withdrawal in mid-G1 phase impaired the association of PI3K with IGF-IR and suppressed DNA synthesis the same as when PI3K inhibitor was added. Furthermore, we demonstrated that Tyr1316-X-X-Met of IGF-IR functioned as a PI3K binding sequence when this tyrosine is phosphorylated. We then analyzed IGF signaling and proliferation of IGF-IR−/− fibroblasts expressing exogenous mutant IGF-IR in which Tyr1316 was substituted with Phe (Y1316F). In these cells, IGF-I stimulation induced tyrosine phosphorylation of IGF-IR and IRS-1/2, but mutated IGF-IR failed to bind PI3K and to induce maximal phosphorylation of GSK3β and cell proliferation in response to IGF-I. Based on these results, we concluded that PI3K activity bound to IGF-IR, which is continuously sustained by IGF-I stimulation, is required for IGF-I-induced cell proliferation. PMID:22767591

Sexual dimorphism in parental imprint ontogeny and contribution to embryonic development.

PubMed

Bourc'his, Déborah; Proudhon, Charlotte

2008-01-30

Genomic imprinting refers to the functional non-equivalence of parental genomes in mammals that results from the parent-of-origin allelic expression of a subset of genes. Parent-specific expression is dependent on the germ line acquisition of DNA methylation marks at imprinting control regions (ICRs), coordinated by the DNA-methyltransferase homolog DNMT3L. We discuss here how the gender-specific stages of DNMT3L expression may have influenced the various sexually dimorphic aspects of genomic imprinting: (1) the differential developmental timing of methylation establishment at paternally and maternally imprinted genes in each parental germ line, (2) the differential dependence on DNMT3L of parental methylation imprint establishment, (3) the unequal duration of paternal versus maternal methylation imprints during germ cell development, (4) the biased distribution of methylation-dependent ICRs towards the maternal genome, (5) the different genomic organization of paternal versus maternal ICRs, and finally (6) the overwhelming contribution of maternal germ line imprints to development compared to their paternal counterparts.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins.

PubMed

González-Guerra, José Luis; Castilla-Cortazar, Inma; Aguirre, Gabriel A; Muñoz, Úrsula; Martín-Estal, Irene; Ávila-Gallego, Elena; Granado, Miriam; Puche, Juan E; García-Villalón, Ángel Luis

2017-01-01

Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins

PubMed Central

Aguirre, Gabriel A.; Muñoz, Úrsula; Martín-Estal, Irene; Ávila-Gallego, Elena; Granado, Miriam; Puche, Juan E.; García-Villalón, Ángel Luis

2017-01-01

Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions. PMID:28806738

Cell cycle distribution, cellular viability and mRNA expression of hGCase-gene-transfected cells in dairy goat.

PubMed

Zhang, Yan-Li; Wan, Yong-Jie; Wang, Zi-Yu; Qi, Wei-Wei; Zhou, Zheng-Rong; Huang, Rong; Wang, Feng

2010-05-07

Nuclear transfer using transgenic donor cells is an efficient way of generating transgenic goats, wherein the preparation of competent transgenic donor cells is the pivotal upstream step. We have measured the efficiency of transfection with a plasmid containing hGCase (human lysosomal acid beta-glucosidase) gene into goat FFC (fetal-derived fibroblast cells), MEC (mammary epithelial cells) and AEFC (adult ear skin-derived fibroblast cells), and the characteristics of cell cycle, apoptosis and chromosome abnormalities after transfection. The expression of genes involved in imprinting [IGF2 (insulin-like growth factor 2), IGF2R (IGF2 receptor)], apoptosis (Bax), stress (heat-shock protein, Hsp70.1), cellular connections [Cx43 (connexin 43)] and DNA methylation [DNMT1 (DNA methyltransferase 1)] in transgenic fetal cells has been investigated. The hGCase transgene was successfully detected in the transfected cell lines, and chromosomal stability remained similar in FFC and transgenic FFC (70.9 compared with 66.8%), whereas a smaller percentage (P<0.05) of cells at G(0)/G(1) in the transgenic FFC, MEC and AEFC (T-FFC, T-MEC and T-AEFC), and higher percentage (P<0.05) of apoptotic cells in T-FFC than the non-transfected controls were detected by flow cytometric analysis. Among the genes tested, the relative expressions of IGF2, IGF2R and transcripts of Cx43 were significantly higher (P<0.05) in T-FFC compared with non-transfected FFC. These novel findings on gene expression in transgenic fetal cells may have certain implications in the biopharming industry and in our understanding the low efficiency of transgenic cloning.

The Gpr1/Zdbf2 locus provides new paradigms for transient and dynamic genomic imprinting in mammals

PubMed Central

Duffié, Rachel; Ajjan, Sophie; Greenberg, Maxim V.; Zamudio, Natasha; Escamilla del Arenal, Martin; Iranzo, Julian; Okamoto, Ikuhiro; Barbaux, Sandrine; Fauque, Patricia; Bourc'his, Déborah

2014-01-01

Many loci maintain parent-of-origin DNA methylation only briefly after fertilization during mammalian development: Whether this form of transient genomic imprinting can impact the early embryonic transcriptome or even have life-long consequences on genome regulation and possibly phenotypes is currently unknown. Here, we report a maternal germline differentially methylated region (DMR) at the mouse Gpr1/Zdbf2 (DBF-type zinc finger-containing protein 2) locus, which controls the paternal-specific expression of long isoforms of Zdbf2 (Liz) in the early embryo. This DMR loses parental specificity by gain of DNA methylation at implantation in the embryo but is maintained in extraembryonic tissues. As a consequence of this transient, tissue-specific maternal imprinting, Liz expression is restricted to the pluripotent embryo, extraembryonic tissues, and pluripotent male germ cells. We found that Liz potentially functions as both Zdbf2-coding RNA and cis-regulatory RNA. Importantly, Liz-mediated events allow a switch from maternal to paternal imprinted DNA methylation and from Liz to canonical Zdbf2 promoter use during embryonic differentiation, which are stably maintained through somatic life and conserved in humans. The Gpr1/Zdbf2 locus lacks classical imprinting histone modifications, but analysis of mutant embryonic stem cells reveals fine-tuned regulation of Zdbf2 dosage through DNA and H3K27 methylation interplay. Together, our work underlines the developmental and evolutionary need to ensure proper Liz/Zdbf2 dosage as a driving force for dynamic genomic imprinting at the Gpr1/Zdbf2 locus. PMID:24589776

The role of selenium in insulin-like growth factor I receptor (IGF-IR) expression and regulation of apoptosis in mouse osteoblasts.

PubMed

Ren, Gaixian; Ali, Tariq; Chen, Wei; Han, Dandan; Zhang, Limei; Gu, Xiaolong; Zhang, Shiyao; Ding, Laidi; Fanning, Séamus; Han, Bo

2016-02-01

Selenium (Se) is an essential component for animals and human beings. The chemoprotective role of Se, via the regulation of the cell cycle, stimulation of apoptosis and activation of some cytokines among others, is well known; however, the comprehensive effects of Se on the expression of IGF-IR and its regulation of apoptosis have not been investigated. Thus the aim of this study was to report on the effects that different concentrations of Se extert on body weight, blood serum IGF-IR levels and histopathology in mice; and on IGF-IR expression, proliferation and apoptosis in mouse osteoblasts. In vivo experiments showed a significant decrease in body weight, serum levels of IGF-IR and prominent toxicant effects on the liver, kidney, heart and spleen following the administration of defined concentrations of Se for 30 d. However, moderate levels (0.1 mg/kg) of Se gradually improved weight and serum IGF-IR. In vitro osteoblast experiments revealed that at concentrations of 5 × 10(-6) and 10(-5) mol/L Se, MTT activity decreased in comparison with control cells. Cell cycle, TEM and caspase-3 activity supported these observations including an increase in the sub-G1 phase and notable apoptosis in osteoblasts, along with a decrease in the expression of mRNA and protein levels of IGF-IR. Moreover, the MTT activity, mRNA and protein levels of IGF-IR in osteoblasts were decreased and caspase-3 activity was increased in siRNA groups as compared with non-siRNA groups. These data suggest that Se significantly affects IGF-IR expression, and that it contributes to the proliferation and regulation of apoptosis in osteoblasts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genomic Imprinting Was Evolutionarily Conserved during Wheat Polyploidization.

PubMed

Yang, Guanghui; Liu, Zhenshan; Gao, Lulu; Yu, Kuohai; Feng, Man; Yao, Yingyin; Peng, Huiru; Hu, Zhaorong; Sun, Qixin; Ni, Zhongfu; Xin, Mingming

2018-01-01

Genomic imprinting is an epigenetic phenomenon that causes genes to be differentially expressed depending on their parent of origin. To evaluate the evolutionary conservation of genomic imprinting and the effects of ploidy on this process, we investigated parent-of-origin-specific gene expression patterns in the endosperm of diploid ( Aegilops spp), tetraploid, and hexaploid wheat ( Triticum spp) at various stages of development via high-throughput transcriptome sequencing. We identified 91, 135, and 146 maternally or paternally expressed genes (MEGs or PEGs, respectively) in diploid, tetraploid, and hexaploid wheat, respectively, 52.7% of which exhibited dynamic expression patterns at different developmental stages. Gene Ontology enrichment analysis suggested that MEGs and PEGs were involved in metabolic processes and DNA-dependent transcription, respectively. Nearly half of the imprinted genes exhibited conserved expression patterns during wheat hexaploidization. In addition, 40% of the homoeolog pairs originating from whole-genome duplication were consistently maternally or paternally biased in the different subgenomes of hexaploid wheat. Furthermore, imprinted expression was found for 41.2% and 50.0% of homolog pairs that evolved by tandem duplication after genome duplication in tetraploid and hexaploid wheat, respectively. These results suggest that genomic imprinting was evolutionarily conserved between closely related Triticum and Aegilops species and in the face of polyploid hybridization between species in these genera. © 2018 American Society of Plant Biologists. All rights reserved.

CD24 cell surface expression in Mvt1 mammary cancer cells serves as a biomarker for sensitivity to anti-IGF1R therapy.

PubMed

Rostoker, Ran; Ben-Shmuel, Sarit; Rashed, Rola; Shen Orr, Zila; LeRoith, Derek

2016-05-14

The pro-tumorigenic effects of the insulin-like growth factor receptor (IGF1R) are well described. IGF1R promotes cancer cell survival and proliferation and prevents apoptosis, and, additionally it was shown that IGF1R levels are significantly elevated in most common human malignancies including breast cancer. However, results from phase 3 clinical trials in unselected patients demonstrated lack of efficacy for anti-IGF1R therapy. These findings suggest that predictive biomarkers are greatly warranted in order to identify patients that will benefit from anti-IGF1R therapeutic strategies. Using the delivery of shRNA vectors into the Mvt1 cell line, we tested the role of the IGF1R in the development of mammary tumors. Based on CD24 cell surface expression, control and IGF1R-knockdown (IGF1R-KD) cells were FACS sorted into CD24(-) and CD24(+) subsets and further characterized in vitro. The tumorigenic capacity of each was determined following orthotopic inoculation into the mammary fat pad of female mice. Tumor cells were FACS characterized upon sacrifice to determine IGF1R effect on the plasticity of this cell's phenotype. Metastatic capacity of the cells was assessed using the tail vein assay. In this study we demonstrate that downregulation of the IGF1R specifically in cancer cells expressing CD24 on the cell surface membrane affect both their morphology (from mesenchymal-like into epithelial-like morphology) and phenotype in vitro. Moreover, we demonstrate that IGF1R-KD abolished both CD24(+) cells capacity to form mammary tumors and lung metastatic lesions. We found in both cells and tumors a marked upregulation in CTFG and a significant reduction of SLP1 expression in the CD24(+)/IGF1R-KD; tumor-suppressor and tumor-promoting genes respectively. Moreover, we demonstrate here that the IGF1R is essential for the maintenance of stem/progenitor-like cancer cells and we further demonstrate that IGF1R-KD induces in vivo differentiation of the CD24(+) cells toward the

The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuloaga, R.; Fuentes, E.N.; Molina, A.

2013-10-18

Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP{sub 3}/calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1more » during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation.« less

Insulin-like growth factors (IGF-I, free IGF-I and IGF-II) and insulin-like growth factor binding proteins (IGFBP-2, IGFBP-3, IGFBP-6, and ALS) in blood circulation.

PubMed

Yu, H; Mistry, J; Nicar, M J; Khosravi, M J; Diamandis, A; van Doorn, J; Juul, A

1999-01-01

Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) play an important role in cell growth and differentiation. Clinical and epidemiological studies have indicated that measuring IGFs and IGFBPs in blood has potential implications in assessing growth-related abnormalities and risks of certain types of cancer. To facilitate the application, we reported a large collection of reference ranges of IGFs and IGFBPs in normal population and evaluations of these molecules in serum and plasma as well as the impact of freeze-thaw cycles on the measurement. IGF-I, IGFBP-3 andALS showed a similar pattern of change associated with age. Levels of these molecules were low at birth and increased with age through puberty. After puberty the levels declined slowly with age. Overall, IGF-I, IGFBP-3 and ALS were slightly higher in females than in males. Free IGF-I accounted for about 1% of the total IGF-I and its variation with age was similar to total IGF-I. IGF-II levels were also increased with age from birth to puberty, but became stable after puberty. There was little difference in IGF-II levels between genders. IGFBP-2 levels declined with age from birth to puberty. Levels of IGFBP-6 in contrast were increased with age. These IGF binding proteins were higher in males than in females. IGFs, IGFBP-3 and ALS were 5-10% higher in serum than in plasma. IGFBP-2 and IGFBP-6 differed substantially between serum and plasma. Freeze-thaw treatment up to five cycles had little impact on plasma levels of IGFs and IGFBP-3. Our observations suggest that levels of IGFs and their binding proteins are varied with age, gender, and types of specimen and that these variations need to be taken into consideration when IGFs and their binding proteins are utilized in clinic and research.

Extracorporeal shock waves promote healing of collagenase-induced Achilles tendinitis and increase TGF-beta1 and IGF-I expression.

PubMed

Chen, Yeung-Jen; Wang, Ching-Jen; Yang, Kuender D; Kuo, Yur-Ren; Huang, Hui-Chen; Huang, Yu-Ting; Sun, Yi-Chih; Wang, Feng-Sheng

2004-07-01

Extracorporeal shock waves (ESW) have recently been used in resolving tendinitis. However, mechanisms by which ESW promote tendon repair is not fully understood. In this study, we reported that an optimal ESW treatment promoted healing of Achilles tendintis by inducing TGF-beta1 and IGF-I. Rats with the collagenease-induced Achilles tendinitis were given a single ESW treatment (0.16 mJ/mm(2) energy flux density) with 0, 200, 500 and 1000 impulses. Achilles tendons were subjected to biomechanical (load to failure and stiffness), biochemical properties (DNA, glycosaminoglycan and hydroxyproline content) and histological assessment. ESW with 200 impulses restored biomechanical and biochemical characteristics of healing tendons 12 weeks after treatment. However, ESW treatments with 500 and 1000 impulses elicited inhibitory effects on tendinitis repair. Histological observation demonstrated that ESW treatment resolved edema, swelling, and inflammatory cell infiltration in injured tendons. Lesion site underwent intensive tenocyte proliferation, neovascularization and progressive tendon tissue regeneration. Tenocytes at the hypertrophied cellular tissue and newly developed tendon tissue expressed strong proliferating cell nuclear antigen (PCNA) after ESW treatment, suggesting that physical ESW could increase the mitogenic responses of tendons. Moreover, the proliferation of tenocytes adjunct to hypertrophied cell aggregate and newly formed tendon tissue coincided with intensive TGF-beta1 and IGF-I expression. Increasing TGF-beta1 expression was noted in the early stage of tendon repair, and elevated IGF-I expression was persisted throughout the healing period. Together, low-energy shock wave effectively promoted tendon healing. TGF-beta1 and IGF-I played important roles in mediating ESW-stimulated cell proliferation and tissue regeneration of tendon.

IGF-1R Promotes Symmetric Self-Renewal and Migration of Alkaline Phosphatase+ Germ Stem Cells through HIF-2α-OCT4/CXCR4 Loop under Hypoxia.

PubMed

Kuo, Yung-Che; Au, Heng-Kien; Hsu, Jue-Liang; Wang, Hsiao-Feng; Lee, Chiung-Ju; Peng, Syue-Wei; Lai, Ssu-Chuan; Wu, Yu-Chih; Ho, Hong-Nerng; Huang, Yen-Hua

2018-02-13

Hypoxia cooperates with endocrine signaling to maintain the symmetric self-renewal proliferation and migration of embryonic germline stem cells (GSCs). However, the lack of an appropriate in vitro cell model has dramatically hindered the understanding of the mechanism underlying this cooperation. Here, using a serum-free system, we demonstrated that hypoxia significantly induced the GSC mesenchymal transition, increased the expression levels of the pluripotent transcription factor OCT4 and migration-associated proteins (SDF-1, CXCR4, IGF-1, and IGF-1R), and activated the cellular expression and translocalization of the CXCR4-downstream proteins ARP3/pFAK. The underlying mechanism involved significant IGF-1/IGF-1R activation of OCT4/CXCR4 expression through HIF-2α regulation. Picropodophyllin-induced inhibition of IGF-1R phosphorylation significantly suppressed hypoxia-induced SDF-1/CXCR4 expression and cell migration. Furthermore, transactivation between IGF-1R and CXCR4 was involved. In summary, we demonstrated that niche hypoxia synergistically cooperates with its associated IGF-1R signaling to regulate the symmetric division (self-renewal proliferation) and cell migration of alkaline phosphatase-positive GSCs through HIF-2α-OCT4/CXCR4 during embryogenesis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Fetal growth restriction and the programming of heart growth and cardiac insulin-like growth factor 2 expression in the lamb.

PubMed

Wang, Kimberley C W; Zhang, Lei; McMillen, I Caroline; Botting, Kimberley J; Duffield, Jaime A; Zhang, Song; Suter, Catherine M; Brooks, Doug A; Morrison, Janna L

2011-10-01

Reduced growth in fetal life together with accelerated growth in childhood, results in a ~50% greater risk of coronary heart disease in adult life. It is unclear why changes in patterns of body and heart growth in early life can lead to an increased risk of cardiovascular disease in adulthood. We aimed to investigate the role of the insulin-like growth factors in heart growth in the growth-restricted fetus and lamb. Hearts were collected from control and placentally restricted (PR) fetuses at 137-144 days gestation and from average (ABW) and low (LBW) birth weight lambs at 21 days of age. We quantified cardiac mRNA expression of IGF-1, IGF-2 and their receptors, IGF-1R and IGF-2R, using real-time RT-PCR and protein expression of IGF-1R and IGF-2R using Western blotting. Combined bisulphite restriction analysis was used to assess DNA methylation in the differentially methylated region (DMR) of the IGF-2/H19 locus and of the IGF-2R gene. In PR fetal sheep, IGF-2, IGF-1R and IGF-2R mRNA expression was increased in the heart compared to controls. LBW lambs had a greater left ventricle weight relative to body weight as well as increased IGF-2 and IGF-2R mRNA expression in the heart, when compared to ABW lambs. No changes in the percentage of methylation of the DMRs of IGF-2/H19 or IGF-2R were found between PR and LBW when compared to their respective controls. In conclusion, a programmed increased in cardiac gene expression of IGF-2 and IGF-2R may represent an adaptive response to reduced substrate supply (e.g. glucose and/or oxygen) in order to maintain heart growth and may be the underlying cause for increased ventricular hypertrophy and the associated susceptibility of cardiomyocytes to ischaemic damage later in life.

Role of androgen receptor on cyclic mechanical stretch-regulated proliferation of C2C12 myoblasts and its upstream signals: IGF-1-mediated PI3K/Akt and MAPKs pathways.

PubMed

Ma, Yiming; Fu, Shaoting; Lu, Lin; Wang, Xiaohui

2017-07-15

To detect the effects of androgen receptor (AR) on cyclic mechanical stretch-modulated proliferation of C2C12 myoblasts and its pathways: roles of IGF-1, PI3K and MAPK. C2C12 were randomly divided into five groups: un-stretched control, six or 8 h of fifteen percent stretch, and six or 8 h of twenty percent stretch. Cyclic mechanical stretch of C2C12 were completed using a computer-controlled FlexCell Strain Unit. Cell proliferation and IGF-1 concentration in medium were detected by CCK8 and ELISA, respectively. Expressions of AR and IGF-1R, and expressions and activities of PI3K, p38 and ERK1/2 in stretched C2C12 cells were determined by Western blot. ①The proliferation of C2C12 cells, IGF-1 concentration in medium, expressions of AR and IGF-1R, and activities of PI3K, p38 and ERK1/2 were increased by 6 h of fifteen percent stretch, while decreased by twenty percent stretch for six or 8 h ②The fifteen percent stretch-increased proliferation of C2C12 cells was reversed by AR inhibitor, Flutamide. ③The increases of AR expression, activities of PI3K, p38 and ERK1/2 resulted from fifteen percent stretch were attenuated by IGF-1 neutralizing antibody, while twenty percent stretch-induced decreases of the above indicators were enhanced by recombinant IGF-1. ④Specific inhibitors of p38, ERK1/2 and PI3K all decreased the expression of AR in fifteen percent and twenty percent of stretched C2C12 cells. Cyclic mechanical stretch modulated the proliferation of C2C12 cells, which may be attributed to the alterations of AR via IGF-1-PI3K/Akt and IGF-1-MAPK (p38, ERK1/2) pathways in C2C12 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Global survey of genomic imprinting by transcriptome sequencing.

PubMed

Babak, Tomas; Deveale, Brian; Armour, Christopher; Raymond, Christopher; Cleary, Michele A; van der Kooy, Derek; Johnson, Jason M; Lim, Lee P

2008-11-25

Genomic imprinting restricts gene expression to a paternal or maternal allele. To date, approximately 90 imprinted transcripts have been identified in mouse, of which the majority were detected after intense interrogation of clusters of imprinted genes identified by phenotype-driven assays in mice with uniparental disomies [1]. Here we use selective priming and parallel sequencing to measure allelic bias in whole transcriptomes. By distinguishing parent-of-origin bias from strain-specific bias in embryos derived from a reciprocal cross of mice, we constructed a genome-wide map of imprinted transcription. This map was able to objectively locate over 80% of known imprinted loci and allowed the detection and confirmation of six novel imprinted genes. Even in the intensely studied embryonic day 9.5 developmental stage that we analyzed, more than half of all imprinted single-nucleotide polymorphisms did not overlap previously discovered imprinted transcripts; a large fraction of these represent novel noncoding RNAs within known imprinted loci. For example, a previously unnoticed, maternally expressed antisense transcript was mapped within the Grb10 locus. This study demonstrates the feasibility of using transcriptome sequencing for mapping of imprinted gene expression in physiologically normal animals. Such an approach will allow researchers to study imprinting without restricting themselves to individual loci or specific transcripts.

Identification of an Imprinted Gene Cluster in the X-Inactivation Center

PubMed Central

Kobayashi, Shin; Totoki, Yasushi; Soma, Miki; Matsumoto, Kazuya; Fujihara, Yoshitaka; Toyoda, Atsushi; Sakaki, Yoshiyuki; Okabe, Masaru; Ishino, Fumitoshi

2013-01-01

Mammalian development is strongly influenced by the epigenetic phenomenon called genomic imprinting, in which either the paternal or the maternal allele of imprinted genes is expressed. Paternally expressed Xist, an imprinted gene, has been considered as a single cis-acting factor to inactivate the paternally inherited X chromosome (Xp) in preimplantation mouse embryos. This means that X-chromosome inactivation also entails gene imprinting at a very early developmental stage. However, the precise mechanism of imprinted X-chromosome inactivation remains unknown and there is little information about imprinted genes on X chromosomes. In this study, we examined whether there are other imprinted genes than Xist expressed from the inactive paternal X chromosome and expressed in female embryos at the preimplantation stage. We focused on small RNAs and compared their expression patterns between sexes by tagging the female X chromosome with green fluorescent protein. As a result, we identified two micro (mi)RNAs–miR-374-5p and miR-421-3p–mapped adjacent to Xist that were predominantly expressed in female blastocysts. Allelic expression analysis revealed that these miRNAs were indeed imprinted and expressed from the Xp. Further analysis of the imprinting status of adjacent locus led to the discovery of a large cluster of imprinted genes expressed from the Xp: Jpx, Ftx and Zcchc13. To our knowledge, this is the first identified cluster of imprinted genes in the cis-acting regulatory region termed the X-inactivation center. This finding may help in understanding the molecular mechanisms regulating imprinted X-chromosome inactivation during early mammalian development. PMID:23940725

Identification of an imprinted gene cluster in the X-inactivation center.

PubMed

Kobayashi, Shin; Totoki, Yasushi; Soma, Miki; Matsumoto, Kazuya; Fujihara, Yoshitaka; Toyoda, Atsushi; Sakaki, Yoshiyuki; Okabe, Masaru; Ishino, Fumitoshi

2013-01-01

Mammalian development is strongly influenced by the epigenetic phenomenon called genomic imprinting, in which either the paternal or the maternal allele of imprinted genes is expressed. Paternally expressed Xist, an imprinted gene, has been considered as a single cis-acting factor to inactivate the paternally inherited X chromosome (Xp) in preimplantation mouse embryos. This means that X-chromosome inactivation also entails gene imprinting at a very early developmental stage. However, the precise mechanism of imprinted X-chromosome inactivation remains unknown and there is little information about imprinted genes on X chromosomes. In this study, we examined whether there are other imprinted genes than Xist expressed from the inactive paternal X chromosome and expressed in female embryos at the preimplantation stage. We focused on small RNAs and compared their expression patterns between sexes by tagging the female X chromosome with green fluorescent protein. As a result, we identified two micro (mi)RNAs-miR-374-5p and miR-421-3p-mapped adjacent to Xist that were predominantly expressed in female blastocysts. Allelic expression analysis revealed that these miRNAs were indeed imprinted and expressed from the Xp. Further analysis of the imprinting status of adjacent locus led to the discovery of a large cluster of imprinted genes expressed from the Xp: Jpx, Ftx and Zcchc13. To our knowledge, this is the first identified cluster of imprinted genes in the cis-acting regulatory region termed the X-inactivation center. This finding may help in understanding the molecular mechanisms regulating imprinted X-chromosome inactivation during early mammalian development.

Genomic Imprinting Was Evolutionarily Conserved during Wheat Polyploidization[OPEN

PubMed Central

Yang, Guanghui; Liu, Zhenshan; Gao, Lulu; Yu, Kuohai; Feng, Man; Peng, Huiru; Sun, Qixin; Ni, Zhongfu

2018-01-01

Genomic imprinting is an epigenetic phenomenon that causes genes to be differentially expressed depending on their parent of origin. To evaluate the evolutionary conservation of genomic imprinting and the effects of ploidy on this process, we investigated parent-of-origin-specific gene expression patterns in the endosperm of diploid (Aegilops spp), tetraploid, and hexaploid wheat (Triticum spp) at various stages of development via high-throughput transcriptome sequencing. We identified 91, 135, and 146 maternally or paternally expressed genes (MEGs or PEGs, respectively) in diploid, tetraploid, and hexaploid wheat, respectively, 52.7% of which exhibited dynamic expression patterns at different developmental stages. Gene Ontology enrichment analysis suggested that MEGs and PEGs were involved in metabolic processes and DNA-dependent transcription, respectively. Nearly half of the imprinted genes exhibited conserved expression patterns during wheat hexaploidization. In addition, 40% of the homoeolog pairs originating from whole-genome duplication were consistently maternally or paternally biased in the different subgenomes of hexaploid wheat. Furthermore, imprinted expression was found for 41.2% and 50.0% of homolog pairs that evolved by tandem duplication after genome duplication in tetraploid and hexaploid wheat, respectively. These results suggest that genomic imprinting was evolutionarily conserved between closely related Triticum and Aegilops species and in the face of polyploid hybridization between species in these genera. PMID:29298834

Prader-Willi Syndrome: Obesity due to Genomic Imprinting

PubMed Central

Butler, Merlin G

2011-01-01

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder due to errors in genomic imprinting with loss of imprinted genes that are paternally expressed from the chromosome 15q11-q13 region. Approximately 70% of individuals with PWS have a de novo deletion of the paternally derived 15q11-q13 region in which there are two subtypes (i.e., larger Type I or smaller Type II), maternal disomy 15 (both 15s from the mother) in about 25% of cases, and the remaining subjects have either defects in the imprinting center controlling the activity of imprinted genes or due to other chromosome 15 rearrangements. PWS is characterized by a particular facial appearance, infantile hypotonia, a poor suck and feeding difficulties, hypogonadism and hypogenitalism in both sexes, short stature and small hands and feet due to growth hormone deficiency, mild learning and behavioral problems (e.g., skin picking, temper tantrums) and hyperphagia leading to early childhood obesity. Obesity is a significant health problem, if uncontrolled. PWS is considered the most common known genetic cause of morbid obesity in children. The chromosome 15q11-q13 region contains approximately 100 genes and transcripts in which about 10 are imprinted and paternally expressed. This region can be divided into four groups: 1) a proximal non-imprinted region; 2) a PWS paternal-only expressed region containing protein-coding and non-coding genes; 3) an Angelman syndrome region containing maternally expressed genes and 4) a distal non-imprinted region. This review summarizes the current understanding of the genetic causes, the natural history and clinical presentation of individuals with PWS. PMID:22043168