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Статті в журналах з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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Cao, Junguo, Qingchun Mu, and Haiyan Huang. "The Roles of Insulin-Like Growth Factor 2 mRNA-Binding Protein 2 in Cancer and Cancer Stem Cells." Stem Cells International 2018 (2018): 1–15. http://dx.doi.org/10.1155/2018/4217259.
Повний текст джерелаАнотація:
RNA-binding proteins (RBPs) mediate the localization, stability, and translation of the target transcripts and fine-tune the physiological functions of the proteins encoded. The insulin-like growth factor (IGF) 2 mRNA-binding protein (IGF2BP, IMP) family comprises three RBPs, IGF2BP1, IGF2BP2, and IGF2BP3, capable of associating with IGF2 and other transcripts and mediating their processing. IGF2BP2 represents the least understood member of this family of RBPs; however, it has been reported to participate in a wide range of physiological processes, such as embryonic development, neuronal differentiation, and metabolism. Its dysregulation is associated with insulin resistance, diabetes, and carcinogenesis and may potentially be a powerful biomarker and candidate target for relevant diseases. This review summarizes the structural features, regulation, and functions of IGF2BP2 and their association with cancer and cancer stem cells.
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Palanichamy, Jayanth Kumar, Tiffany Tran, Jorge Contreras, Thilini R. Fernando, and Dinesh S. Rao. "Role Of Insulin Like Growth Factor mRNA Binding Protein-3 (IGF2BP3) In Mixed Lineage Leukemia (MLL) Positive B-Cell Lymphomas." Blood 122, no. 21 (November 15, 2013): 3816. http://dx.doi.org/10.1182/blood.v122.21.3816.3816.
Повний текст джерелаАнотація:
Abstract Oncogenic transformation of early B-cell progenitors leads to the human disease of B-acute lymphoblastic leukemia or B-ALL, which affects both children and adults. Among the different subtypes of B-ALL, defined by particular cytogenetic anomalies, there are two which are difficult to treat and have a dismal prognosis. These are B-ALL with chromosomal translocation t (9; 22)/BCR-ABL and MLL gene rearrangements, which show distinctive gene expression profiles. Gene expression is now known to be significantly regulated by post-transcriptional mechanisms. These involve RNA binding proteins and microRNAs. Deregulation of microRNAs as well as RNA binding protein expression is associated with numerous cancers. Here, we hypothesized that RNA binding proteins may be important in regulating gene expression in MLL rearranged leukemias. To examine this hypothesis, we undertook a microarray study examining the expression of both protein-coding and non-coding genes in B-ALL, including MLL translocations. A total of 44 samples were used for the microarray. Supervised class prediction was carried out using the R library of prediction analysis for microarrays (PAM). One of the most significantly differentially expressed genes was Insulin Like Growth Factor mRNA Binding Protein-3 (IGF2BP3). The expression of IGF2BP3 was highest in the MLL rearranged B-ALL group. IGF2BP3 is an oncofetal protein known to be highly expressed in a number of epithelial malignancies such as glioblastomas. IGF2BP3 has been known to bind to the 5’-UTR and stabilize mRNAs like CD44 the expression of which correlates with epithelial tumors metastasis. IGF2BP3 has been shown to bind to the Insulin like Growth Factor-2 (IGF-2) mRNA and enhance translation in glioblastomas. We confirmed the expression of IGF2BP3 and CD44 in these 44 tumor samples and 90 other B-cell lymphoma samples by RT-qPCR. This corroborated with our previous data showing that the expression of both these genes is significantly higher in the group with MLL translocations. In the MLL rearranged leukemias, there was a significant correlation between the expression of CD44 and IGF2BP3. Interestingly however, there was no significant difference in the expression of IGF2 mRNA between these different subsets, indicating either that IGF2BP3 might be acting on IGF-2 mRNA at the translational level or that IGF-2 regulation may be cell-type specific. To evaluate whether IGF2BP3 affects the growth of B-ALL cells, we used NALM6, a B-ALL cell line which expresses IGF2BP3. We generated microRNA-155 formatted siRNAs against human IGF2BP3 and subcloned them into pHAGE6 based lentiviral vectors. Our preliminary data demonstrates that these vectors are capable of knocking down IGF2BP3 in the NALM6 cell line. In addition, cells with knockdown showed a dramatic decrease in their growth rates, as measured by the MTS assay. The IGF-2 paracrine signaling system is thought to be important in the maintenance of HSCs as well as in lymphocyte development. We separated different precursors of B-cells (Hardy fractions) from murine bone marrow using FACS and measured the mRNA expression of CD44 and IGF2BP3 in these different subsets. The expression of both these genes correlated well with each other and showed a dynamic expression pattern with the highest expression seen in the Hardy Fraction C (late pro-B cells). This indicates that the IGF2BP3/CD44 axis might play a role in regulating normal B-cell development and this may be dysregulated in MLL-translocated B-ALL. To examine whether IGF2BP3 overexpression causes leukemia, we cloned the murine and human IGF2BP3 coding regions in a murine retroviral expression vector, MIG (MSCV-IGF2BP3-IRES-GFP). Retroviral packaging was done using 293T cell line, virus was collected and used to infect 7Oz/3, a murine pre-B ALL cell line. Western blot and qPCR confirmed overexpression of IGF2BP3. We have infected bone marrow cells from CD 45.2 positive wild type donor mice with the virus and transferred them into irradiated CD 45.1 recipient mice. We have confirmed engraftment in these mice using flowcytometry for CD 45.1/2 and are presently following the mice for the development of leukemia. In summary, IGF2BP3 is dysregulated in MLL-rearranged leukemia, and its knockdown can cause decreased growth rates in B-ALL cell lines. The current study explores whether IGF2BP3 is oncogenic and the mechanisms of action of IGF2BP3 in B-cell development and neoplasia. Disclosures: No relevant conflicts of interest to declare.
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Yin, Huadong, Haorong He, Xiaoxu Shen, Jing Zhao, Xinao Cao, Shunshun Han, Can Cui, et al. "miR-9-5p Inhibits Skeletal Muscle Satellite Cell Proliferation and Differentiation by Targeting IGF2BP3 through the IGF2-PI3K/Akt Signaling Pathway." International Journal of Molecular Sciences 21, no. 5 (February 28, 2020): 1655. http://dx.doi.org/10.3390/ijms21051655.
Повний текст джерелаАнотація:
MicroRNAs are evolutionarily conserved, small non-coding RNAs that play critical post-transcriptional regulatory roles in skeletal muscle development. We previously found that miR-9-5p is abundantly expressed in chicken skeletal muscle. Here, we demonstrate a new role for miR-9-5p as a myogenic microRNA that regulates skeletal muscle development. The overexpression of miR-9-5p significantly inhibited the proliferation and differentiation of skeletal muscle satellite cells (SMSCs), whereas miR-9-5p inhibition had the opposite effect. We show that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is a target gene of miR-9-5p, using dual-luciferase assays, RT-qPCR, and Western Blotting, and that it promotes proliferation and differentiation of SMSCs. In addition, we found that IGF2BP3 regulates IGF-2 expression, using overexpression and knockdown studies. We show that Akt is activated by IGF2BP3 and is essential for IGF2BP3-induced cell development. Together, our results indicate that miR-9-5p could regulate the proliferation and differentiation of myoblasts by targeting IGF2BP3 through IGF-2 and that this activity results in the activation of the PI3K/Akt signaling pathway in skeletal muscle cells.
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Wächter, Kristin, Marcel Köhn, Nadine Stöhr, and Stefan Hüttelmaier. "Subcellular localization and RNP formation of IGF2BPs (IGF2 mRNA-binding proteins) is modulated by distinct RNA-binding domains." Biological Chemistry 394, no. 8 (August 1, 2013): 1077–90. http://dx.doi.org/10.1515/hsz-2013-0111.
Повний текст джерелаАнотація:
Abstract The IGF2 mRNA-binding protein family (IGF2BPs) directs the cytoplasmic fate of various target mRNAs and controls essential cellular functions. The three IGF2BP paralogues expressed in mammals comprise two RNA-recognition motifs (RRM) as well as four KH domains. How these domains direct IGF2BP paralogue-dependent protein function remains largely elusive. In this study, we analyze the role of KH domains in IGF2BPs by the mutational GXXG-GEEG conversion of single KH domain loops in the context of full-length polypeptides. These analyses reveal that all four KH domains of IGF2BP1 and IGF2BP2 are essentially involved in RNA-binding in vitro and the cellular association with RNA-binding proteins (RBPs). Moreover the KH domains prevent the nuclear accumulation of these two paralogues and facilitate their recruitment to stress granules. The role of KH domains appears less pronounced in IGF2BP3, because GxxG-GEEG conversion in all four KH domains only modestly affects RNA-binding, subcellular localization and RNA-dependent protein association of this paralogue. These findings indicate paralogue-dependent RNA-binding properties of IGF2BPs which likely direct distinct cellular functions. Our findings suggest that IGF2BPs contact target RNAs via all four KH domains. This implies significant structural constraints, which presumably allow the formation of exceedingly stable protein-RNA complexes.
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Wang, Peng-Fei, Xiaoyu Wang, Min Liu, Zheng Zeng, Caiji Lin, Wenwen Xu, Wenqing Ma, et al. "The Oncogenic Functions of Insulin-like Growth Factor 2 mRNA-Binding Protein 3 in Human Carcinomas." Current Pharmaceutical Design 26, no. 32 (September 24, 2020): 3939–54. http://dx.doi.org/10.2174/1381612826666200413080936.
Повний текст джерелаАнотація:
IGF2BP3 (also known as IMP3, KOC), a member of the insulin-like growth factor mRNA-binding protein family (IMPs), has been a research target in recent studies of promoting embryo development and exacerbating cancer. IGF2BP3 is ubiquitously expressed in early embryogenesis stages but limited in postembryonic stages, which is important in many physiological aspects such as stem cell renewal, morphological development and metabolism. A large number of studies show that IGF2BP3 interacts with many kinds of non-coding RNAs and proteins to promote cancer cell proliferation and metastasis and inhibit cancer cell apoptosis. As IGF2BP3 is highly expressed in advanced cancers and associated with poor overall survival rates of patients, it may be a potential molecular marker in cancer diagnosis for the detection of cancerous tissues and an indicator of cancer stages. Therefore, anti-IGF2BP3 drugs or monoclonal antibodies are expected as new therapeutic methods in cancer treatment. This review summarizes recent findings among IGF2BP3, RNA and proteins in cancer processes, with a focus on its cancer-promoting mechanisms and potential application as a new biomarker for cancer diagnosis and treatment.
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Panebianco, Federica, Lindsey M. Kelly, Pengyuan Liu, Shan Zhong, Sanja Dacic, Xiaosong Wang, Aatur D. Singhi, et al. "THADA fusion is a mechanism of IGF2BP3 activation and IGF1R signaling in thyroid cancer." Proceedings of the National Academy of Sciences 114, no. 9 (February 13, 2017): 2307–12. http://dx.doi.org/10.1073/pnas.1614265114.
Повний текст джерелаАнотація:
Thyroid cancer development is driven by known point mutations or gene fusions found in ∼90% of cases, whereas driver mutations in the remaining tumors are unknown. The insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) plays an important role in cancer, yet the mechanisms of its activation in cancer cells remain poorly understood. Using whole-transcriptome and whole-genome analyses, we identified a recurrent fusion between the thyroid adenoma-associated (THADA) gene on chromosome 2 and the LOC389473 gene on chromosome 7 located 12 kb upstream of the IGF2BP3 gene. We show that THADA fusion to LOC389473 and other regions in the vicinity does not result in the formation of a chimeric protein but instead leads to strong overexpression of the full-length IGF2BP3 mRNA and protein, increased IGF2 translation and IGF1 receptor (IGF1R) signaling via PI3K and MAPK cascades, and promotion of cell proliferation, invasion, and transformation. THADA fusions and IGF2BP3 overexpression are found in ∼5% of thyroid cancers that lack any other driver mutations. We also find that strong IGF2BP3 overexpression via gene fusion, amplification, or other mechanisms occurs in 5 to 15% of several other cancer types. Finally, we provide in vitro and in vivo evidence that growth of IGF2BP3-driven cells and tumors may be blocked by IGF1R inhibition, raising the possibility that IGF2BP3 overexpression in cancer cells may predict an anti-IGF1R benefit.
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Zhang, Haotian, Junjie Tang, Xiaowei Gong, and Chenjun Huang. "Insulin-Like Growth Factor 2 mRNA Binding Protein 3 Suppresses Ferroptosis in Non-Small Cell Lung Cancer via Stabilizing m6A Modification of Fanconi Anemia Group D2 Protein." Journal of Biomedical Nanotechnology 19, no. 8 (August 1, 2023): 1390–99. http://dx.doi.org/10.1166/jbn.2023.3643.
Повний текст джерелаАнотація:
This study investigated the role of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) in non-small cell lung cancer (NSCLC) and its association with N6-methyladenosine (m6A) modification. The study analyzes the expression levels and stability of IGF2BP3, as well as its impact on NSCLC cell functions. The findings indicate that IGF2BP3 is upregulated in NSCLC patients and cell lines. Knocking down IGF2BP3 reduces cell proliferation and promotes ferroptosis in A549 and H1299 cells. Additionally, the study reveals that IGF2BP3 regulates the m6A modification of the fanconi anemia group D2 protein (FANCD2) and influences its mRNA stability. Overexpressing FANCD2 counteracts the effects of IGF2BP3 silencing and increases the aggressiveness of NSCLC. Furthermore, treatment with celastrol induces ferroptosis in NSCLC cells and inhibits tumor growth in vivo. In conclusion, these findings suggest that IGF2BP3 acts as an oncogene in NSCLC. Its interaction with FANCD2 through m6A modification suppresses ferroptosis in NSCLC cells. Thus, the IGF2BP3/FANCD2 signaling pathway may serve as a potential therapeutic target for NSCLC.
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de Vasconcellos, Jaira F., Colleen Byrnes, Y. Terry Lee, Pauline C. Xu, Antoinette Rabel, and Jeffery L. Miller. "IGF2BP3 Moderately Increases Fetal Hemoglobin Levels in Human Adult Erythroblasts." Blood 128, no. 22 (December 2, 2016): 2464. http://dx.doi.org/10.1182/blood.v128.22.2464.2464.
Повний текст джерелаАнотація:
Abstract Recent studies demonstrated that IGF2BP1 over-expression (IGF2BP1-OE) in adult erythroblasts has robust effects on fetal hemoglobin (HbF; >65% of the total globin levels), accompanied by reversal of the beta-like globin expression patterns to a fetal-like phenotype. Here we investigated if another member of the insulin-like growth factor 2 mRNA-binding protein family, IGF2BP3, also has potential for HbF regulation that may be useful for therapeutic application among patients with beta-hemoglobin disorders. The developmental pattern and expression levels for IGF2BP3 were initially determined in cord blood versus adult blood CD34(+) samples cultivated ex vivo in erythropoietin-supplemented serum-free media for 21 days. RNA samples were collected at culture day 14 and expression levels were measured by qRT-PCR. IGF2BP3 showed a developmentally regulated expression pattern similar to IGF2BP1 (IGF2BP1: cord blood: 1.3.E+03 ± 4.3.E+02 and adult blood: below detection limits; IGF2BP3: cord blood: 5.8.E+02 ± 2.4.E+02 and adult blood: below detection limits). These results were confirmed in vivo by comparing human fetal liver to adult bone marrow samples (IGF2BP1: fetal liver: 3.5.E+02 ± 5.7.E+01, adult bone marrow: below detection limits and IGF2BP3: fetal liver: 2.0.E+01 ± 2.7.E+00, adult bone marrow: below detection limits). To investigate the effects of IGF2BP3 upon erythropoiesis and globin expression, a lentiviral construct was designed for expression of IGF2BP3 driven by the erythroid-specific gene promoter region of the human SPTA1 gene (IGF2BP3-OE), with a matched empty vector control. Transductions were performed in CD34(+) cells from four adult healthy volunteers cultivated ex vivo in erythropoietin-supplemented serum-free media for 21 days. Over-expression of IGF2BP3 was confirmedby qRT-PCR and Western blot analyses at culture day 14. IGF2BP3-OE cells maintained their ability to differentiate and enucleate ex vivo compared to donor-matched controls. The expression levels of globin genes were evaluated at culture day 14 by qRT-PCR and showed that IGF2BP3-OE caused significantly increased gamma-globin expression levels compared to control transductions (control: 7.7.E+05 ± 1.7.E+05; IGF2BP3-OE: 8.4.E+06 ± 3.2.E+06; p=0.018). Consistent with increased gamma-globin, HbF rose to moderately high levels upon IGF2BP3-OE (control: 4.0 ± 2.1%; IGF2BP3-OE: 18.6 ± 1.0%; p=0.0021). In addition, the expression pattern of the erythroid transcription factor BCL11A was investigated by qRT-PCR at culture day 14 and no significant changes were observed (control: 5.6.E+02 ± 2.7.E+02; IGF2BP3-OE: 6.7.E+02 ± 3.5.E+02; p=0.694). However, minor decreases in BCL11A protein levels were detected by Western analysis. These results demonstrate that IGF2BP3 is developmentally regulated in human erythroid tissues with silencing during the fetal-to-adult transition. However, the effects of IGF2BP3-OE on HbF levels were less robust when compared to IGF2BP1-OE in cultured adult erythroblasts. Disclosures No relevant conflicts of interest to declare.
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Zhang, Jing, Fanghui Ding, Dan Jiao, Qiaozhi Li, and Hong Ma. "The Aberrant Expression of MicroRNA-125a-5p/IGF2BP3 Axis in Advanced Gastric Cancer and Its Clinical Relevance." Technology in Cancer Research & Treatment 19 (January 1, 2020): 153303382091733. http://dx.doi.org/10.1177/1533033820917332.
Повний текст джерелаАнотація:
RNA-binding proteins have been associated with cancer development. The overexpression of a well-known RNA-binding protein, insulin-like growth factor 2 messenger RNA–binding protein 3, has been identified as an indicator of poor prognosis in patients with various types of cancer. Although gastric cancer is a relatively frequent and potentially fatal malignancy, the mechanism by which insulin-like growth factor 2 messenger RNA–binding protein 3 regulates the development of this cancer remains unclear. This study aimed to investigate the role and regulatory mechanism of insulin-like growth factor 2 messenger RNA–binding protein 3 in gastric cancer. An analysis of IGF2BP3 expression patterns reported in 4 public gastric cancer–related microarray data sets from the Gene Expression Omnibus and The Cancer Genome Atlas-Stomach Adenocarcinoma revealed strong expression of this gene in gastric cancer tissues. Insulin-like growth factor 2 messenger RNA–binding protein 3 expression in gastric cancer was further confirmed via quantitative reverse transcription polymerase chain reaction and immunohistochemistry, respectively, in an in-house gastric cancer cohort (n = 30), and the association of insulin-like growth factor 2 messenger RNA–binding protein 3 expression with clinical parameters and prognosis was analyzed. Notably, stronger IGF2BP3 expression significantly correlated with poor prognosis, and significant changes in insulin-like growth factor 2 messenger RNA–binding protein 3 expression were only confirmed in patients with advanced-stage gastric cancer in an independent cohort. The effects of insulin-like growth factor 2 messenger RNA–binding protein 3 on cell proliferation were confirmed through in vitro experiments involving the HGC-27 gastric cancer cell line. MicroR-125a-5p, a candidate microRNA that target on insulin-like growth factor 2 messenger RNA–binding protein 3, decreased in advanced-stage gastric cancer. Upregulation of microR-125a-5p inhibited insulin-like growth factor 2 messenger RNA–binding protein 3, and dual-luciferase report assay indicated that microR-125a-5p inhibited the translation of IGF2BP3 by directly targeting the 3′ untranslated region. These results indicate that the microR-125a-5p/insulin-like growth factor 2 messenger RNA–binding protein 3 axis contributes to the oncogenesis of advanced gastric cancer.
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Liu, Xin, Jiayu Chen, Wenliang Chen, Yangtao Xu, Yang Shen, and Ximing Xu. "Targeting IGF2BP3 in Cancer." International Journal of Molecular Sciences 24, no. 11 (May 29, 2023): 9423. http://dx.doi.org/10.3390/ijms24119423.
Повний текст джерелаАнотація:
RNA-binding proteins (RBPs) can regulate multiple pathways by binding to RNAs, playing a variety of functions, such as localization, stability, and immunity. In recent years, with the development of technology, researchers have discovered that RBPs play a key role in the N6-methyladenosine (m6A) modification process. M6A methylation is the most abundant form of RNA modification in eukaryotes, which is defined as methylation on the sixth N atom of adenine in RNA. Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is one of the components of m6A binding proteins, which plays an important role in decoding m6A marks and performing various biological functions. IGF2BP3 is abnormally expressed in many human cancers, often associated with poor prognosis. Here, we summarize the physiological role of IGF2BP3 in organisms and describe its role and mechanism in tumors. These data suggest that IGF2BP3 may be a valuable therapeutic target and prognostic marker in the future.
Дисертації з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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Simon, Yvette [Verfasser], and Alexandra K. [Akademischer Betreuer] Kiemer. "The insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IGF2BP2-2 amplifies steatosis, inflammation, and fibrosis in murine non-alcoholic steatohepatitis (NASH) / Yvette Simon. Betreuer: Alexandra K. Kiemer." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2013. http://d-nb.info/1053681836/34.
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Okeke, Joy C. "The Effects of Ellagic Acid on Insulin-Like Growth Factor Binding Protein-2 in Human Prostate Cancer Cells." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1162343994.
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Laggai, Stephan [Verfasser], and Alexandra K. [Akademischer Betreuer] Kiemer. "Hepatic steatosis and cancer development : role of insulin-like growth factor 2 mRNA binding protein p62, IGF2BP2, IMP2-2 and fatty acid elongase ELOVL6 / Stephan Laggai. Betreuer: Alexandra K. Kiemer." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1059390469/34.
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Bayayibign, Biruhalem Assefa [Verfasser]. "Insulin-like growth factor (IGF) binding protein-2, independently of IGF-1, induces GLUT-4 translocation and glucose uptake in 3T3-L1 adipocytes / Biruhalem Assefa Bayayibign." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2018. http://d-nb.info/1172074402/34.
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Bode-Rhoads, Michelle Lynn. "Regulation of the growth hormone receptor, insulin-like growth factor (IGF) I and IGF binding protein 2 in reproductive tissues of dairy cattle during lactation and associated effects on fertility." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3164490.
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Meichsner, Anke [Verfasser]. "Konstruktion einer nicht-IGF-bindenden Insulin-like Growth Factor Binding Protein-2-Variante und Untersuchung ihrer Wirkung auf das Tumorzellwachstum / Anke Meichsner." Magdeburg : Universitätsbibliothek, 2012. http://d-nb.info/1053227299/34.
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Robinson, Rose Marie. "Regulation of Bovine Mammary Epithelial Cell Response by Autocrine IGF-I and by Collagen I." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/26520.
Повний текст джерелаАнотація:
Understanding how insulin-like growth factor-I (IGF-I) signaling in mammary epithelial cells may be modified or interrupted by modifications in the cellular environment may lead to 1) methods to increase the growth and proliferation of normal mammary epithelial cells for an increase in the amount of milk produced on a per animal basis or to 2) the development of medical interventions to disrupt the growth and proliferation of cancerous mammary epithelial cells. IGF-I, a signaling protein provided by stromal cells and through the bloodstream, stimulates the proliferation of mammary epithelial cells and is crucial for mammary development. Collagen I is an extracellular matrix protein (ECM) found in skin and in other connective tissues throughout the body. The guiding question in this dissertation was how IGF-I signaling and how binding protein profile were influenced by autocrine IGF-I and by collagen I. The MAC-T cell line was chosen as the cell model utilized in these investigations because it is an immortalized bovine mammary epithelial cell line known to retain hormonal responsiveness to IGF-I.
It was hypothesized that the production of IGF-I by mammary epithelial cells (autocrine secretion) would alter the response of these cells to additional IGF-I by de-sensitizing the IGF-I receptor on the cell surface. The normal mammary epithelial cell does not produce IGF-I and responds to IGF-I supplied either by stromal cells (paracrine pathway) or through the bloodstream (endocrine pathway). The IGF-I secreting bovine mammary epithelial cell line was investigated for the response of the cells to autocrine IGF-I, and the response was compared to the normal, parental cell line. To examine the effect of autocrine IGF-I on the cells, IGF-I was added both to MAC-T cells and to cells transfected to secrete IGF-I (SV40-IGF-I). The cell response of the two cell lines was compared using microphysiometry, a tool that measures IGF-IR stimulation by detecting resultant extracellular acidification. It was found that the SV40-IGF-I cell line retains IGF-I receptor sensitivity, yet, unlike the parental cell line, does not proliferate in response to IGF-I. Both cell lines exhibited increased protein synthesis in response to IGF-I as measured by amino acid uptake (AIB incorporation), but the lack of a proliferation response to additional IGF-I in the SV40-IGF-I cell line suggested that the autocrine cell line exhibited an un-coupling of IGF-IR stimulation with downstream cell proliferation. Both autocrine IGF-I and added IGF-I increased the amount of IGFBP-3 secreted by the cells into growth media.
Additionally, it was hypothesized that the presence of collagen I, an important ECM protein, would alter the cell production of insulin-like binding protein-3 (IGFBP-3), a protein that modulates IGF-I interaction with the IGF-I receptor (IGF-IR). The literature reports that surface substrate can affect the phenotypic expression of cells, presumably via interaction with integrins, the cell surface receptors that connect cells to ECM proteins and that are responsible for cell adhesion and for cell migration. It was hypothesized that the MAC-T cells would interact with a collagen I surface (possibly via the a2b1 integrin) and that the stimulation of this transmembrane signaling molecule would in turn impact the IGF-I signaling pathway. Comparison studies on tissue culture plastic, collagen I BIOCOAT, and collagen I gel were performed. It was found that collagen I gel increased IGFBP-3 secretion and decreased insulin-like binding protein-2 (IGFBP-2) secretion in MAC-T cells. The collagen I BIOCOAT did not induce this response.
Additional studies were performed to determine if there were differences in IGF-IR phosphorylation, exogenous IGF-I utilization, and IGFBP mRNA production by cells cultured on the three different substrates. IGF-IR phosphorylation was only evident following the addition of IGF-I to MAC-T cells on all three substrates. Measurement of residual IGF-I present in the cultured media of cells on all three substrates by radioimmunoassay did not reveal any differences in the amount of IGF-I present. Northern blot analysis revealed that the addition of IGF-I caused an increase in detected IGFBP-3 mRNA and a decrease in detected IGFBP-2 mRNA across all three surfaces. As measured by ligand blot analysis, cells cultured on all three surfaces showed an increase in IGFBP-3 protein in the media with IGF-I addition, and the collagen I gel showed more IGFBP-3 protein than the other two surfaces. However, cells cultured on collagen I gel showed a decrease in IGFBP-2 protein expression compared to cells cultured on tissue culture both with and without the addition of IGF-I. Cells cultured on tissue culture plastic and on collagen I BIOCOAT did not show a decrease in IGFBP-2 to correspond with the decreased IGFBP-2 mRNA detected in the presence of IGF-I on all three substrates. DNA assays to detect cell proliferation revealed no differences in cell DNA content in the absence of exogenous IGF-I and revealed similar increases in response to IGF-I addition on all three substrates.
In conclusion, it was found that autocrine IGF-I un-couples increased IGF-IR stimulation by exogenous IGF-I from a downstream cell proliferation response. IGFBP-3 inhibits the ability of IGF-I to interact with the IGF-IR in MAC-T cells and inhibits subsequent cell proliferation. Collagen I gel increases IGFBP-3 secretion and decreases IGFBP-2 secretion by MAC-T cells.
The relevance of this work is that it adds to the body of knowledge in understanding cellular function in mammary epithelial cells. It is known that the growth and the maintenance of living tissue are dependent on an intricate system of intercellular and intracellular responses which are orchestrated by the movement and secretion of proteins and other molecules. Goals of understanding mammary epithelial cell function include having the means to find ways to increase cell functionality via bioengineering and having the means to find ways to restore cells to normal function in disease processes such as cancer.Ph. D.
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Pazaitis, Nikolaos [Verfasser], Stefan [Gutachter] Hüttelmaier, Jan-Henning [Gutachter] Klussmann, and Martin [Gutachter] Pichler. "In vitro und in vivo Untersuchungen zur Tumorigenität des Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) : [kumulative Dissertation] / Nikolaos Pazaitis ; Gutachter: Stefan Hüttelmaier, Jan-Henning Klussmann, Martin Pichler." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2020. http://d-nb.info/122112997X/34.
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Lubik, Amy Anne. "The role of insulin and IGF2 signalling on metabolic pathways in prostate cancer progression." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/49029/1/Amy_Lubik_Thesis.pdf.
Повний текст джерелаАнотація:
Prostate cancer (CaP) is the most commonly diagnosed cancer in males in Australia, North America, and Europe. If found early and locally confined, CaP can be treated with radical prostatectomy or radiation therapy; however, 25-40% patients will relapse and go on to advanced disease. The most common therapy in these cases is androgen deprivation therapy (ADT), which suppresses androgen production from the testis. Lack of the testicular androgen supply causes cells of the prostate to undergo apoptosis. However, in some cases the regression initially seen with ADT eventually gives way to a growth of a population of cancerous cells that no longer require testicular androgens. This phenotype is essentially fatal and is termed castrate resistant prostate cancer (CRPC). In addition to eventual regression, there are many undesirable side effects which accompany ADT, including development of a metabolic syndrome, which is defined by the U.S. National Library of Medicine as “a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes.” This project will focus on the effect of ADT induced hyperinsulinemia, as mimicked by treating androgen receptor positive CaP cells with insulin in a serum (hormone) deprived environment. While this side effect is not widely explored, in this thesis it is demonstrated for the first time that insulin upregulates pathways important to CaP progression.
Our group has previously shown that during CaP progression, the enzymes necessary for de novo steroidogenesis are upregulated in the LNCaP xenograft model, total steroid levels are increased in tumours compared to pre castrate levels, and de novo steroidogenesis from radio-labelled acetate has been demonstrated. Because of the CaP dependence on AR for survival, we and other groups believe that CaP cells carry out de novo steroidogenesis to survive in androgen deprived conditions. Because (a) men on ADT often develop metabolic syndrome, and (b) men with lifestyle-induced obesity and hyperinsulinemia have worse prognosis and faster disease progression, and because (c) insulin causes steroidogenesis in other cell lines, the hypothesis that insulin may contribute to CaP progression through upregulation of steroidogenesis was explored.
Insulin upregulates steroidogenesis enzymes at the mRNA level in three AR positive cell lines, as well as upregulating these enzymes at the protein level in two cell lines. It has also been demonstrated that insulin increases mitochondrial (functional) levels of steroid acute regulatory protein (StAR). Furthermore, insulin causes increased levels of total steroids in and induction of de novo steroid synthesis by insulin has been demonstrated at levels induced sufficient to activate AR.
The effect of insulin analogs on CaP steroidogenesis in LNCaP and VCaP cells has also been investigated because epidemiological studies suggest that some of the analogs developed may have more cancer stimulatory effects than normal insulin. In this project, despite the signalling differences between glargine, X10, and insulin, these analogs did not appear to induce steroidogenesis any more potently that normal insulin. The effect of insulin of MCF7breast cancer cells was also investigated with results suggesting that breast cancer cells may be capable of de novo steroidogenesis, and that increase in estradiol production may be exacerbated by insulin.
Insulin has also been long known to stimulate lipogenesis in the liver and adipocytes, and has been demonstrated to increase lipogenesis in breast cancer cells; therefore, investigation of the effect of insulin on lipogenesis, which is a hallmark of aggressive cancers, was investigated. In CaP progression sterol regulatory element binding protein (SREBP) is dysregulated and upregulates fatty acid synthase (FASN), acetyl CoA-carboxylase, and other lipogenesis genes. SREBP is important for steroidogenesis and in this project has been shown to be upregulated by insulin in CaP cells. Fatty acid synthesis provides building blocks of membrane growth, provides substrates for acid oxidation, the main energy source for CaP cells, provides building blocks for anti-apoptotic and proinflammatory molecules, and provides molecules that stimulate steroidogenesis. In this project it has been shown that insulin upregulates FASN and ACC, which synthesize fatty acids, as well as upregulating hormone sensitive lipase (HSL), diazepam-binding inhibitor (DBI), and long-chain acyl-CoA synthetase 3 (ACSL3), which contribute to lipid activation of steroidogenesis. Insulin also upregulates total lipid levels and de novo lipogenesis, which can be suppressed by inhibition of the insulin receptor (INSR). The fatty acids synthesized after insulin treatment are those that have been associated with CaP; furthermore, microarray data suggests insulin may upregulate fatty acid biosynthesis, metabolism and arachidonic acid metabolism pathways, which have been implicated in CaP growth and survival.
Pharmacological agents used to treat patients with hyperinsulinemia/ hyperlipidemia have gained much interest in regards to CaP risk and treatment; however, the scientific rationale behind these clinical applications has not been examined. This thesis explores whether the use of metformin or simvastatin would decrease either lipogenesis or steroidogenesis or both in CaP cells. Simvastatin is a 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibitor, which blocks synthesis of cholesterol, the building block of steroids/ androgens. It has also been postulated to down regulate SREBP in other metabolic disorders. It has been shown in this thesis, in LNCaP cells, that simvastatin inhibited and decreased insulin induced steroidogenesis and lipogenesis, respectively, but increased these pathways in the absence of insulin. Conversely, metformin, which activates AMP-activated protein kinase (AMPK) to shut down lipogenesis, cholesterol synthesis, and protein synthesis, highly suppresses both steroidogenesis and lipogenesis in the presence and absence of insulin.
Lastly, because it has been demonstrated to increase steroidogenesis in other cell lines, and because the elucidation of any factors affecting steroidogenesis is important to understanding CaP, the effect of IGF2 on steroidogenesis in CaP cells was investigated. In patient samples, as men progress to CRPC, IGF2 mRNA and the protein levels of the receptors it may signal through are upregulated. It has also been demonstrated that IGF2 upregulates steroidogenic enzymes at both the mRNA and protein levels in LNCaP cells, increases intracellular and secreted steroid/androgen levels in LNCaPs to levels sufficient to stimulate the AR, and upregulated de novo steroidogenesis in LNCaPs and VCaPs. As well, inhibition of INSR and insulin-like growth factor 1 receptor (IGF1R), which IGF2 signals through, suggests that induction of steroidogenesis may be occurring predominantly through IGF1R.
In summary, this project has illuminated for the first time that insulin is likely to play a large role in cancer progression, through upregulation of the steroidogenesis and lipogenesis pathways at the mRNA and protein levels, and production levels, and demonstrates a novel role for IGF-II in CaP progression through stimulation of steroidogenesis. It has also been demonstrated that metformin and simvastatin drugs may be useful in suppressing the insulin induction of these pathways. This project affirms the pathways by which ADT- induced metabolic syndrome may exacerbate CaP progression and strongly suggests that the monitoring and modulation of the metabolic state of CaP patients could have a strong impact on their therapeutic outcomes.
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Yen-YuLiu and 劉彥妤. "The clinical significances and regulatory mechanisms of IGF2 mRNA-binding protein 3 (IGF2BP3) in hepatocellular carcinoma." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/d6ean7.
Повний текст джерелаКниги з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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C, Baxter R., Gluckman Peter D, and Rosenfeld Ron G, eds. The insulin-like growth factors and their regulatory proteins: Proceedings of the Third International Symposium on Insulin-Like Growth Factors, Sydney, 6-10 February 1994. Amsterdam: Excerpta Medica, 1994.
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Baxter, R. C., and Peter D. Gluckman. The Insulin-Like Growth Factors and Their Regulatory Proteins: Proceedings of the Third International Symposium on Insulin-Like Growth Factors, Sydn (International Congress Series). Elsevier Science Pub Co, 1994.
Знайти повний текст джерелаЧастини книг з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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Li, Mingyu, Xiaozhi Rong, Dahong Chen, Ling Lu, Yun Li, and Cunming Duan. "Molecular and Functional Characterization of an IGF-II mRNA Binding Protein-(IGF2BP2b) Gene in Zebrafish." In BASIC/TRANSLATIONAL - IGF & IGF Binding Proteins, P1–136—P1–136. The Endocrine Society, 2011. http://dx.doi.org/10.1210/endo-meetings.2011.part1.p6.p1-136.
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Deochand, Chetram, Ming Tong, Amit R. Agarwal, Enrique Cadenas, and Suzanne M. de la Monte. "Tobacco Smoke Exposure Impairs Brain Insulin/IGF Signaling: Potential Co-Factor Role in Neurodegeneration." In Advances in Alzheimer’s Disease. IOS Press, 2021. http://dx.doi.org/10.3233/aiad210015.
Повний текст джерелаАнотація:
Background: Human studies suggest tobacco smoking is a risk factor for cognitive impairment and neurodegeneration, including Alzheimer’s disease (AD). However, experimental data linking tobacco smoke exposures to underlying mediators of neurodegeneration, including impairments in brain insulin and insulin-like growth factor (IGF) signaling in AD are lacking. Objective: This study tests the hypothesis that cigarette smoke (CS) exposures can impair brain insulin/IGF signaling and alter expression of AD-associated proteins. Methods: Adult male A/J mice were exposed to air for 8 weeks (A8), CS for 4 or 8 weeks (CS4, CS8), or CS8 followed by 2 weeks recovery (CS8+R). Gene expression was measured by qRT-PCR analysis and proteins were measured by multiplex bead-based or direct binding duplex ELISAs. Results: CS exposure effects on insulin/IGF and insulin receptor substrate (IRS) proteins and phosphorylated proteins were striking compared with the mRNA. The main consequences of CS4 or CS8 exposures were to significantly reduce insulin R, IGF-1R, IRS-1, and tyrosine phosphorylated insulin R and IGF-1R proteins. Paradoxically, these effects were even greater in the CS8+R group. In addition, relative levels of S312-IRS-1, which inhibits downstream signaling, were increased in the CS4, CS8, and CS8+R groups. Correspondingly, CS and CS8+R exposures inhibited expression of proteins and phosphoproteins required for signaling through Akt, PRAS40, and/or p70S6K, increased AβPP-Aβ, and reduced ASPH protein, which is a target of insulin/IGF-1 signaling. Conclusion: Secondhand CS exposures caused molecular and biochemical abnormalities in brain that overlap with the findings in AD, and many of these effects were sustained or worsened despite short-term CS withdrawal.
Тези доповідей конференцій з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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Fowke, Jay H., Scott Williams, Herbert Yu, Lisa Signorello, and William J. Blot. "Abstract PR-1: Genetic African ancestry and race differences in blood insulin-like growth factor 1 (IGF-1), IGF-2, and IGF binding protein 3 (IGFBP-3)." In Abstracts: AACR International Conference on the Science of Cancer Health Disparities‐‐ Sep 30-Oct 3, 2010; Miami, FL. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1055-9965.disp-10-pr-3.
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Mancarella, Caterina, Linda Calzolari, Stefano Ferrari, Davide Donati, Piero Picci, and Katia Scotlandi. "Abstract 3201: Insulin-like growth factor 2 (IGF-2) mRNA binding protein 3 predicts poor prognosis and promotes cell proliferation in Ewing sarcoma." In Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-3201.
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Sperling, F., L. Nietfeld, H. Griesmann, K. Theuerkorn, S. Hüttelmaier, and P. Michl. "Charakterisierung von IGF2-mRNA-Binding Proteinen (IGF2BPs/IMPs) in exokrinen und neuroendokrinen Tumorzellen des Pankreas." In Viszeralmedizin 2017. Georg Thieme Verlag KG, 2017. http://dx.doi.org/10.1055/s-0037-1605121.
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Mancarella, Caterina, Maria Cristina Manara, Arthur M. Mercurio, and Katia Scotlandi. "Abstract 3672: Insulin-like growth factor 2 (IGF-2) mRNA binding protein 3-mediated regulation of CD164-CXCR4 axis impacts aggressiveness of Ewing sarcoma." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.am2019-3672.
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Mancarella, Caterina, Maria Cristina Manara, Arthur M. Mercurio, and Katia Scotlandi. "Abstract 3672: Insulin-like growth factor 2 (IGF-2) mRNA binding protein 3-mediated regulation of CD164-CXCR4 axis impacts aggressiveness of Ewing sarcoma." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.sabcs18-3672.
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Pfaff, Liza E., Brian T. Kalet, Deanna D. Dailey, and Dawn L. Duval. "Abstract A23: Insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) drives growth, metastasis and chemoresistance in human and canine osteosarcoma." In Abstracts: AACR Special Conference: The Translational Impact of Model Organisms in Cancer; November 5-8, 2013; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1557-3125.modorg-a23.
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Faye, Mame Daro, Tyson Graber, Stephanie Langlois, Kyle Cowan, and Martin Holcik. "Abstract 827: Identification of the insulin-like growth factor 2 mRNA binding protein (IGF2BP1) as an important regulator of cIAP1 translation and apoptosis in rhabdomyosarcomas." In Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC. American Association for Cancer Research, 2013. http://dx.doi.org/10.1158/1538-7445.am2013-827.
Повний текст джерелаЗвіти організацій з теми "IGF-2 Binding Protein-2 (IGF2BP3)"
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Hansen, Peter J., and Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, September 2007. http://dx.doi.org/10.32747/2007.7587730.bard.
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The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
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Funkenstein, Bruria, and Cunming Duan. GH-IGF Axis in Sparus aurata: Possible Applications to Genetic Selection. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7580665.bard.
Повний текст джерелаАнотація:
Many factors affect growth rate in fish: environmental, nutritional, genetics and endogenous (physiological) factors. Endogenous control of growth is very complex and many hormone systems are involved. Nevertheless, it is well accepted that growth hormone (GH) plays a major role in stimulating somatic growth. Although it is now clear that most, if not all, components of the GH-IGF axis exist in fish, we are still far from understanding how fish grow. In our project we used as the experimental system a marine fish, the gilthead sea bream (Sparus aurata), which inhabits lagoons along the Mediterranean and Atlantic coasts of Europe, and represents one of the most important fish species used in the mariculture industry in the Mediterranean region, including Israel. Production of Sparus is rapidly growing, however, in order for this production to stay competitive, the farming of this fish species has to intensify and become more efficient. One drawback, still, in Sparus extensive culture is that it grows relatively slow. In addition, it is now clear that growth and reproduction are physiological interrelated processes that affect each other. In particular sexual maturation (puberty) is known to be closely related to growth rate in fish as it is in mammals, indicating interactions between the somatotropic and gonadotropic axes. The goal of our project was to try to identify the rate-limiting components(s) in Sparus aurata GH-IGF system which might explain its slow growth by studying the ontogeny of growth-related genes: GH, GH receptor, IGF-I, IGF-II, IGF receptor, IGF-binding proteins (IGFBPs) and Pit-1 during early stages of development of Sparus aurata larvae from slow and fast growing lines. Our project was a continuation of a previous BARD project and could be divided into five major parts: i) obtaining additional tools to those obtained in the previous project that are necessary to carry out the developmental study; ii) the developmental expression of growth-related genes and their cellular localization; iii) tissue-specific expression and effect of GH on expression of growth-related genes; iv) possible relationship between GH gene structure, growth rate and genetic selection; v) the possible role of the IGF system in gonadal development. The major findings of our research can be summarized as follows: 1) The cDNAs (complete or partial) coding for Sparus IGFBP-2, GH receptor and Pit-1 were cloned. Sequence comparison reveals that the primary structure of IGFBP-2 protein is 43-49% identical to that of zebrafish and other vertebrates. Intensive efforts resulted in cloning a fragment of 138 nucleotides, coding for 46 amino acids in the proximal end of the intracellular domain of GH receptor. This is the first fish GH receptor cDNA that had been cloned to date. The cloned fragment will enable us to complete the GH - receptor cloning. 2) IGF-I, IGF-II, IGFBP-2, and IGF receptor transcripts were detected by RT-PCR method throughout development in unfertilized eggs, embryos, and larvae suggesting that these mRNAs are products of both the maternal and the embryonic genomes. Preliminary RT-PCR analysis suggest that GH receptor transcript is present in post-hatching larvae already on day 1. 3) IGF-1R transcripts were detected in all tissues tested by RT-PCR with highest levels in gill cartilage, skin, kidney, heart, pyloric caeca, and brain. Northern blot analysis detected IGF receptor only in gonads, brain and gill cartilage but not in muscle; GH increased slightly brain and gill cartilage IGF-1R mRNA levels. 4) IGFBP-2 transcript were detected only in liver and gonads, when analyzed by Northern blots; RT-PCR analysis revealed expression in all tissues studied, with the highest levels found in liver, skin, gonad and pyloric caeca. 5) Expression of IGF-I, IGF-II, IGF-1R and IGFBP-2 was analyzed during gonadal development. High levels of IGF-I and IGFBP-2 expression were found in bisexual young gonads, which decreased during gonadal development. Regardless of maturational stage, IGF-II levels were higher than those of IGF-L 6) The GH gene was cloned and its structure was characterized. It contains minisatellites of tandem repeats in the first and third introns that result in high level of genetic polymorphism. 7) Analysis of the presence of IGF-I and two types of IGF receptor by immunohistochemistry revealed tissue- and stage-specific expression during larval development. Immunohistochemistry also showed that IGF-I and its receptors are present in both testicular and ovarian cells. Although at this stage we are not able to pinpoint which is the rate-limiting step causing the slow growth of Sparus aurata, our project (together with the previous BARD) yielded a great number of experimental tools both DNA probes and antibodies that will enable further studies on the factors regulating growth in Sparus aurata. Our expression studies and cellular localization shed new light on the tissue and developmental expression of growth-related genes in fish.
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Meidan, Rina, and Robert Milvae. Regulation of Bovine Corpus Luteum Function. United States Department of Agriculture, March 1995. http://dx.doi.org/10.32747/1995.7604935.bard.
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The main goal of this research plan was to elucidate regulatory mechanisms controlling the development, function of the bovine corpus luteum (CL). The CL contains two different sterodigenic cell types and therefore it was necessary to obtain pure cell population. A system was developed in which granulosa and theca interna cells, isolated from a preovulatory follicle, acquired characteristics typical of large (LL) and small (SL) luteal cells, respectively, as judged by several biochemical and morphological criteria. Experiments were conducted to determine the effects of granulosa cells removal on subsequent CL function, the results obtained support the concept that granulosa cells make a substaintial contribution to the output of progesterone by the cyclic CL but may have a limited role in determining the functional lifespan of the CL. This experimental model was also used to better understand the contribution of follicular granulosa cells to subsequent luteal SCC mRNA expression. The mitochondrial cytochrome side-chain cleavage enzyme (SCC), which converts cholesterol to pregnenolone, is the first and rate-limiting enzyme of the steroidogenic pathway. Experiments were conducted to characterize the gene expression of P450scc in bovine CL. Levels of P450scc mRNA were higher during mid-luteal phase than in either the early or late luteal phases. PGF 2a injection decreased luteal P450scc mRNA in a time-dependent manner; levels were significantly reduced by 2h after treatment. CLs obtained from heifers on day 8 of the estrous cycle which had granulosa cells removed had a 45% reduction in the levels of mRNA for SCC enzymes as well as a 78% reduction in the numbers of LL cells. To characterize SCC expression in each steroidogenic cell type we utilized pure cell populations. Upon luteinization, LL expressed 2-3 fold higher amounts of both SCC enzymes mRNAs than SL. Moreover, eight days after stimulant removal, LL retained their P4 production capacity, expressed P450scc mRNA and contained this protein. In our attempts to establish the in vitro luteinization model, we had to select the prevulatory and pre-gonadotropin surge follicles. The ratio of estradiol:P4 which is often used was unreliable since P4 levels are high in atretic follicles and also in preovulatory post-gonadotropin follicles. We have therefore examined whether oxytocin (OT) levels in follicular fluids could enhance our ability to correctly and easily define follicular status. Based on E2 and OT concentrations in follicular fluids we could more accurately identify follicles that are preovulatory and post gonadotropin surge. Next we studied OT biosynthesis in granulosa cells, cells which were incubated with forskolin contained stores of the precursor indicating that forskolin (which mimics gonadotropin action) is an effective stimulator of OT biosynthesis and release. While studying in vitro luteinization, we noticed that IGF-I induced effects were not identical to those induced by insulin despite the fact that megadoses of insulin were used. This was the first indication that the cells may secrete IGF binding protein(s) which regonize IGFs and not insulin. In a detailed study involving several techniques, we characterized the species of IGF binding proteins secreted by luteal cells. The effects of exogenous polyunsaturated fatty acids and arachidonic acid on the production of P4 and prostanoids by dispersed bovine luteal cells was examined. The addition of eicosapentaenoic acid and arachidonic acid resulted in a dose-dependent reduction in basal and LH-stimulated biosynthesis of P4 and PGI2 and an increase in production of PGF 2a and 5-HETE production. Indomethacin, an inhibitor of arachidonic acid metabolism via the production of 5-HETE was unaffected. Results of these experiments suggest that the inhibitory effect of arachidonic acid on the biosynthesis of luteal P4 is due to either a direct action of arachidonic acid, or its conversion to 5-HETE via the lipoxgenase pathway of metabolism. The detailed and important information gained by the two labs elucidated the mode of action of factors crucially important to the function of the bovine CL. The data indicate that follicular granulosa cells make a major contribution to numbers of large luteal cells, OT and basal P4 production, as well as the content of cytochrome P450 scc. Granulosa-derived large luteal cells have distinct features: when luteinized, the cell no longer possesses LH receptors, its cAMP response is diminished yet P4 synthesis is sustained. This may imply that maintenance of P4 (even in the absence of a Luteotropic signal) during critical periods such as pregnancy recognition, is dependent on the proper luteinization and function of the large luteal cell.