A distal super enhancer mediates estrogen-dependent mouse uterine–specific gene transcription of Igf1 (insulin-like growth factor 1) (original) (raw)
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Role of ERα in Mediating Female Uterine Transcriptional Responses to IGF1
Endocrinology, 2017
Estrogen (E2) signaling through its nuclear receptor, E2 receptor α (ERα) increases insulinlike growth factor 1 (IGF1) in the rodent uterus, which then initiates further signals via the IGF1 receptor. Directly administering IGF1 results in similar biological and transcriptional uterine responses. Our studies using global ERα-null mice demonstrated a loss of uterine biological responses of the uterus to E2 or IGF1 treatment, while maintaining transcriptional responses to IGF1. To address this discrepancy in the need for uterine ERα in mediating the IGF1 transcriptional vs growth responses, we assessed the IGF1 transcriptional responses in PgrCre+Esr1f/f (called ERαUtcKO) mice, which selectively lack ERα in progesterone receptor (PGR) expressing cells, including all uterine cells, while maintaining ERα expression in other tissues and cells that do not express Pgr. Additionally, we profiled IGF1-induced ERα binding sites in uterine chromatin using chromatin immunoprecipitation sequenci...
Endocrinology, 2002
IGF-I is a critical regulator of uterine growth, and locally produced uterine IGF-I could mediate the effects of 17-E2 on growth and cellular proliferation. We used IGF-I knockout (KO) mice and tissue grafting to determine the roles of local and systemic IGF-I in uterine growth and E2 responsiveness. Uteri from adult KO mice and neonatal and adult wild-type (WT) mice were grown under the renal capsule of female athymic mice for 4 wk. Initial uterine weights of adult KO and neonatal WT mice were 5% or less of those of adult WT uteri. Weights of adult WT uterine grafts did not increase during grafting. Weights of adult KO and neonatal WT uteri exposed to normal systemic levels of IGF-I in athymic hosts increased 20-to 30-fold to equal or exceed those of adult WT grafts. Uterine epithelial height, reduced in KO mice, was restored to WT levels in KO uteri grafted into athymic hosts. The absence of local IGF-I production in KO uteri did not impair E2induced epithelial proliferation in KO uterine grafts. Neonatal WT uteri grafted into KO hosts showed minimal growth, providing evidence that local uterine IGF-I production is insufficient to support uterine growth in the absence of systemic IGF-I. E2 treatment of KO females produced minimal uterine growth, confirming that lack of IGF-I, rather than E2, caused the uterine hypoplasia. In summary, systemic IGF-I supports normal uterine growth and E2 response in the absence of local IGF-I. Local IGF-I is not a direct mediator of E2 action in uterus, and systemic IGF-I may be more important than previously thought for growth of the uterus and other tissues.
Journal of Biological Chemistry, 2002
In the uterus insulin-like growth factor-1 (IGF-1) signaling can be initiated by estradiol acting through its nuclear receptor (estrogen receptor (ER)) to stimulate the local synthesis of IGF-1. Conversely, in vitro studies have demonstrated that estradiol-independent ER transcriptional activity can be induced by IGF-1 signaling, providing evidence for a cross-talk mechanism between IGF-1 and ER. To investigate whether ER␣ is required for uterine responses to IGF-1 in vivo, both wild-type (WT) and ER␣ knockout (␣ERKO) mice were administered IGF-1, and various uterine responses to IGF-1 were compared. In both WT and ␣ERKO mice, IGF-1 treatment resulted in phosphorylation of uterine IGF-1 receptor (IGF-1R) and formation of an IGF-1R/insulin receptor substrate-1/ phosphatidylinositol 3-kinase signaling complex. In addition, IGF-1 stimulated phosphorylation of uterine Akt and MAPK in both WT and ␣ERKO mice. However, IGF-1 treatment stimulated BrdUrd incorporation and proliferating cell nuclear antigen expression in WT uteri only. To determine whether ER␣ can be activated in vivo by IGF-1 signaling, transgenic mice carrying a luciferase gene driven by two estrogen response elements (ERE-luciferase mice) were utilized. Treatment of ovariectomized ERE-luciferase mice with IGF-1 resulted in an increase in uterine luciferase activity that was attenuated in the presence of the ER antagonist ICI 182,780. Together these data demonstrate that 1) functional signaling proximal to IGF-1R is maintained in the ␣ERKO mouse uterus, 2) ER␣ is necessary for IGF-1 induction of uterine nuclear proliferative responses, and 3) cross-talk between IGF-1R and ER signaling pathways exists in vivo.
Journal of Molecular Endocrinology, 1999
The coexpression of IGF (-I and -II) peptides, corresponding receptors, and IGF binding proteins (IGFBPs) in uterine endometrium suggests that a significant component of IGF action in this tissue is via autocrine or paracrine pathways, or both. The present study examined whether IGF-II and a major uterine-expressed IGF-II binding protein, IGFBP-2, modulate endometrial epithelial cell mitogenesis. Serum-deprived porcine endometrial glandular epithelial (GE) cells of early pregnancy were treated with various concentrations of IGFs, recombinant porcine (rp) IGFBP-2, or both, and examined for changes in cellular mitogenesis by incorporation of [ 3 H]thymidine into DNA. Recombinant human (rh) IGF-II stimulated DNA synthesis in a dose-dependent manner. Human [Leu 27 ]-IGF-II, an analog with selective affinity for the IGF-II (type II) receptor, increased thymidine uptake by twofold compared with untreated GE cells. When added in combination with an equimolar concentration of rhIGF-I, [Leu 27 ]-IGF-II or rhIGF-II stimulated thymidine incorporation to a greater extent than did rhIGF-I alone. Ligand blot analysis of GE cell conditioned medium revealed the presence of four IGFBPs with molecular masses of 48, 31, 23, and 15 kDa. Physiological concentrations of rpIGFBP-2 (nM range) increased both basal and IGF-induced DNA synthesis in GE cells. At equimolar concentrations, Des(1-6)IGF-II (an IGF-II analog with much reduced affinity for IGFBPs) and rpIGFBP-2 had additive effects on GE cell mitogenesis, suggesting that the IGFBP-2 modulation of uterine cell growth may involve both IGF-dependent and IGF-independent pathways. Our results demonstrate the complex interplay of IGF system components in uterine endometrial epithelial growth regulation in vitro, identify IGF-II and IGFBP-2 as locally coexpressed uterine epithelial cell mitogens, and suggest the presence of a functional signaling pathway by which IGF-II stimulates epithelial cell proliferation via the type II receptor.
DNA and Cell Biology, 2006
The regulation of insulin-like growth factor-binding protein-2 (IGFBP-2) gene transcription in specific cell and developmental contexts is not well understood. Here, we identified DNA regions that mediate IGFBP-2 gene transcription in two of the three major cell types of the uterine endometrium of the early pregnant pig. Two clusters of transcriptional start sites at nucleotides ؊109/؊105 and ؊96/؊87 (؉1, translational initiation site) in the porcine IGFBP-2 gene were localized in uterine endometrium and in primary cultures of endometrial glandular epithelial (GE) and stromal (ST) fibroblastic cells. Upstream regions of this gene (spanning ؊1397/؉73) were fused to a luciferase reporter gene, and the constructs were transiently transfected into endometrial GE and ST cells representative of pregnancy days 12 and 18 (day 115 ؍ parturition). A short (110 bp) upstream region (؊874/؊765) stimulated the IGFBP-2 and heterologous SV40 promoters in the two cell types at both pregnancy days. Two noncontiguous copies of the novel sequence motif TCAGGG within the 110-bp fragment were implicated in transcriptional activity, since block mutation of these sequences led to a repression of SV40 basal promoter activity in endometrial cells. Southwestern blotting identified an endometrial nuclear protein of 34-kDa molecular weight that bound an oligonucleotide containing this motif, and EMSA suggested robust expression of this protein in early pregnancy endometrium and in ovary but at much reduced levels in endometrium at later pregnancy. A pair of E-box elements (CANNTG) within the 110 bp region was stimulatory to IGFBP-2 promoter activity; block mutation of these converted the 110-bp region into a potent transcriptional silencer in all but day 18 ST cells. Results identify novel DNA motifs that regulate the IGFBP-2 gene promoter in uterine endometrium in pregnancy-associated fashion. KWAK ET AL. 16 FIG. 8. Mutation of E-boxes negates enhancer-like activity of the 110-bp fragment. DNAs were transfected in day 12 ST and GE, and day 18 ST and GE cells. Results for D12 GE and D18 ST cells were from three independent experiments (n ϭ 3 pigs) with each construct tested in triplicate per experiment. Results for D12 ST and D18 GE cells were from four independent experiments (n ϭ 4 pigs). *SV40P and SV40P-110 are different; † SV40P-110 and E-mut-110 are different; P Ͻ 0.05.
Endocrinology, 2000
Recent data indicate that insulin-like growth factor I (IGF-I) may have a function in mediating the mitogenic effects of 17-estradiol (E 2) in the uterus and in regulating the growth of uterine neoplasms. This study was designed to determine whether synthetic and plantderived chemicals that interact with estrogen receptor-␣ (ER␣) and elicit estrogenic responses also mimic E 2 by activating the uterine IGF-I signaling pathway. Ovariectomized adult female mice were treated with both environmental and clinically relevant chemicals previously reported to display estrogenic and/or antiestrogenic properties, and their uteri were evaluated for an activated IGF-I signaling pathway. Diethylstilbestrol, 4-hydroxytamoxifen, the raloxifene analog LY353381, 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE), bis-phenol A, and genistein were shown to mimic E 2 in the uterus by increasing the level of IGF-I messenger RNA, inducing IGF-I receptor (IGF-IR) tyrosine phosphorylation, stimulating the formation of IGF-IR signaling complexes, and increasing both proliferating cell nuclear antigen expression and the number of mitotic cells in the epithelium. The dose of chemical necessary to activate IGF-I signaling varied, with the order of potency: E 2 ϭ diethylstilbestrol Ͼ LY353381 Ͼ 4-hydroxytamoxifen Ͼ genistein Ͼ HPTE Ͼ bisphenol A. Administration of the chemicals to ER␣ knockout mice did not activate IGF-IR, indicating that ER␣ is required for activation of uterine IGF-IR by these diverse chemicals. This study demonstrates that several chemicals shown previously to display estrogenic activities also mimic E 2 by activating uterine IGF-I signaling.
Physiological genomics, 2007
17beta-Estradiol (E2) is well known to be associated with uterine cancer, endometriosis, and leiomyomas. Although insulin-like growth factor I (IGF-I) has been identified as a mediator of the uterotrophic effect of E2 in several studies, this mechanism is still not well understood. In the present study, identification of the genes modulated by a physiological dose of E2, in the uterus, has been done in ovariectomized mice using Affymetrix microarrays. The E2-induced genomic profile shows that multiple genes belonging to the IGF-I pathway are affected after exposure to E2. Two phases of regulation could be identified. First, from 0 to 6 h, the expression of genes involved in the cell cycle, growth factors, protein tyrosine phosphatases, and MAPK phosphatases is quickly upregulated by E2, while IGF-I receptor and several genes of the MAPK and phosphatidylinositol 3-kinase pathways are downregulated. Later, i.e., from 6 to 24 h, transporters and peptidases/proteases are stimulated, whe...
2016
transcriptional induction of PTP and MKP and downregulation of IGF-I pathway key components in the mouse uterus. Physiol Genomics 29: 13–23, 2007; doi:10.1152/physiolgenomics.00291.2005.—17-Estradiol (E2) is well known to be associated with uterine cancer, endometriosis, and leiomyomas. Although insulin-like growth factor I (IGF-I) has been identified as a mediator of the uterotrophic effect of E2 in several studies, this mechanism is still not well understood. In the present study, identification of the genes modulated by a physio-logical dose of E2, in the uterus, has been done in ovariectomized mice using Affymetrix microarrays. The E2-induced genomic profile shows that multiple genes belonging to the IGF-I pathway are affected after exposure to E2. Two phases of regulation could be identified. First, from 0 to 6 h, the expression of genes involved in the cell cycle, growth factors, protein tyrosine phosphatases, and MAPK phospha-tases is quickly upregulated by E2, while IGF-I re...
Roles of insulin-like growth factor II in regulating female reproductive physiology
Science China Life Sciences, 2020
The number of growth factors involved in female fertility has been extensively studied, but reluctance to add essential growth factors in culture media has limited progress in optimizing embryonic growth and implantation outcomes, a situation that has ultimately led to reduced pregnancy outcomes. Insulin-like growth factor II (IGF-II) is the most intricately regulated of all known reproduction-related growth factors characterized to date, and is perhaps the predominant growth factor in human ovarian follicles. This review aims to concisely summarize what is known about the role of IGF-II in follicular development, oocyte maturation, embryonic development, implantation success, placentation, fetal growth, and in reducing placental cell apoptosis, as well as present strategies that use growth factors in culture systems to improve the developmental potential of oocytes and embryos in different species. Synthesizing the present knowledge about the physiological roles of IGF-II in follicular development, oocyte maturation, and early embryonic development should, on the one hand, deepen our overall understanding of the potential beneficial effects of growth factors in female reproduction and on the other hand support development (optimization) of improved outcomes for assisted reproductive technologies.