Mouse embryonic stem cells and preimplantation embryos require signaling through the phosphatidylinositol 3‐kinase pathway to suppress apoptosis

Gross, Vera; Hess, Mailee; Cooper, Geoffrey M.

doi:10.1002/mrd.20212

Cited by 35 publications

(29 citation statements)

References 53 publications

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“…Previously we and others demonstrated that the PI3K pathway is present and functional during murine preimplantation development (32,34,35,42); however, there is still relatively little data regarding the physiologic ramifications of inhibiting this pathway in preimplantation embryos. Because of the connection between the PI3K signal transduction pathway, growth factors, and cell survival in other systems (18,43), we first investigated whether inhibition of PI3K results in the induction of apoptosis.…”

Section: Resultsmentioning

confidence: 99%

“…There is a deficit in the number of homozygous knock-out embryos detected at E3.5 (blastocyst stage) implying that this protein is important during early development. In addition, studies have shown that the inhibition of PI3K leads to decreased numbers of embryos that develop to the morula and blastocyst stage when cultured in vitro and to the induction of apoptosis during this developmental period (34,35).…”

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confidence: 99%

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Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

Riley

Carayannopoulos

Wyman

et al. 2006

Journal of Biological Chemistry

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The phosphatidylinositol 3-kinase (PI3K) signal transduction pathway is a well known mediator of cell growth, proliferation, and survival signals. Whereas the expression and function of this pathway has been documented during mammalian development, evidence demonstrating the physiologic importance of this pathway in murine preimplantation embryos is beginning to emerge. This study demonstrates that inhibition of the PI3K pathway leads to the induction of apoptosis in both murine blastocysts and trophoblast stem cells. The apoptosis induced in both model systems correlates with a decrease in the expression of the glucose transporter GLUT1 at the plasma membrane. In addition, blastocysts cultured in the presence of the PI3K inhibitor LY-294002 display a decrease in both 2-deoxyglucose uptake and hexokinase activity as compared with control blastocysts. To determine the impact of PI3K inhibition on pregnancy outcome, embryo transfer experiments were performed. Blastocysts cultured in the presence of LY-294002 demonstrate a dramatic increase in fetal resorptions as compared with control embryos. Finally, we demonstrate that impairment of glucose metabolism via iodoacetate, a glyceraldehyde-3-phosphate dehydrogenase inhibitor, is sufficient to induce apoptosis in both blastocysts and trophoblast stem cells. Moreover, blastocysts treated with iodoacetate result in poor pregnancy outcome as determined by embryo transfer experiments. Taken together these data demonstrate the critical importance of the PI3K pathway in preimplantation embryo survival and pregnancy outcome and further emphasize the importance of glucose utilization and metabolism in cell survival pathways.The blastocyst stage of murine preimplantation development occurs approximately 4 days post-fertilization. At this stage of embryonic development the first cell differentiation step has occurred. The blastocyst is comprised of the epithelial trophectoderm, which is the layer of cells that develop into the placenta, and the inner cell mass, which consists of the pluripotent cells that gives rise to the embryo proper. Prior to implantation, the developing embryo is dependent on signals generated by growth factors that are either made by the embryo itself or are present in the maternal environment. These growth factors are known to regulate cellular proliferation and differentiation during mammalian preimplantation development (1, 2). Importantly, the preimplantation embryo expresses a number of growth factor receptors known to activate the phosphatidylinositol 3-kinase (PI3K) 2 pathway including the insulin and insulin-like growth factor-I receptors (3, 4).PI3K is a lipid kinase that phosphorylates the D-3 position on the inositol ring in phosphoinositides (5-7). It is a heterodimeric enzyme that consists of an 85-kDa regulatory subunit and a 110-kDa catalytic subunit. A number of extracellular signals activate PI3K including insulin and other growth factors. Insulin and insulin-like growth factor-I have been shown to have both mitogenic and anti-apoptotic ...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

Riley

Carayannopoulos

Wyman

et al. 2006

Journal of Biological Chemistry

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“…Also, several studies reported that IGF-I promotes pre-implantation embryo development and cell numbers in many species, including mouse [15], cow [18], and human [17]. The antiapoptotic effects of IGF-I generally act through a phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway which subsequently inactivates pro-apoptotic proteins such as Bad and caspase-9 and stimulates anti-apoptotic proteins, including Bcl-2, a number of transcription factors and translational regulatory proteins [41,42]. Therefore, IGF-I may promote embryonic development by an anti-apoptotic effect instead of increasing HIF-1α expression.…”

Section: Discussionmentioning

confidence: 99%

Effects of oxygen tension and IGF-I on HIF-1α protein expression in mouse blastocysts

Yoon

Juhn

et al. 2012

J Assist Reprod Genet

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Purpose Hypoxia inducible factors (HIFs) are key regulators of oxygen homeostasis in response to reduced oxygenation in somatic cells. In addition, HIF-1α protein can be also induced by insulin-like growth factor I (IGF-I) treatment in various cell lines under normoxic condition. However, the expression and function of HIF-1α in embryogenesis are still unclear. Therefore, the objectives of this study were to examine the expression of HIF-1α in mouse blastocysts cultured under hypoxic and normoxic conditions, and to determine whether oxygen tension and IGF-I influence embryonic development through stimulation of HIF-1α expression. Methods Mouse embryos were cultured from the 1-cell to blastocyst stage under 5 % or 20 % O 2 in both the absence and presence of IGF-I. Results The embryonic development rates to the blastocyst stage were not affected by oxygen tension or IGF-I treatment. HIF-1α protein was localized to the cytoplasm of blastocysts, and its levels were independent of oxygen concentration or IGF-I treatment. Blastocysts cultured under 5 % O 2 exhibited significantly higher total cell numbers (83.4±18.1) and lower apoptotic index (3.7±1.5) than those cultured under 20 % O 2 (67.4±15.6) (6.9±3.5) (P<0.05). IGF-I reduced the apoptotic index in both oxygen conditions, but a significant decrease was detected in the 20 % O 2 group. Conclusions HIF-1α may not be a major mediator that responds to change in oxygen tension within blastocysts, inconsistent with that of somatic cells. Supplementation of culture media with IGF-I has been shown to promote embryo development by an anti-apoptotic effect, instead of increasing HIF-1α protein expression.

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“…In Experiment, 2 the effect of LY294002 [27], an inhibitor of PI3K-a second messenger present in the mouse preimplantation embryo involved in the maintenance of pluripotency [25,28]-was examined in the presence or absence of insulin to determine whether insulin was acting via PI3K. Since the PI3K second messenger pathway involves the subsequent phosphorylation and inactivation of GSK3 [29], which has been shown to be beneficial for maintaining cells in a pluripotent state in outgrown ICMs [30], we hypothesized that the activation of GSK3 would inhibit the positive response of insulin, while inactivation would mimic the effects of insulin.…”

Section: Experimental Designmentioning

confidence: 99%

Insulin Increases Epiblast Cell Number of In Vitro Cultured Mouse Embryos via the PI3K/GSK3/p53 Pathway

Campbell

Nottle

Vassiliev

et al. 2012

Stem Cells and Development

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Authors may also deposit this version on his/her funder's or funder's designated repository at the funder's request or as a result of a legal obligation, provided it is not made publicly available until 12 months after official publication. th March 2013Insulin High-quality embryos give rise to embryonic stem cells (ESCs) at greater efficiencies than poor-quality embryos. However, most embryos available for human ESC derivation are of a reduced quality as a result of culture in relatively simple media up to 10 years earlier, before cryopreservation, or before compaction. In the present study, we used a mouse model to determine whether a culture with insulin from the 8-cell stage could increase the number of ESC progenitor epiblast cells in blastocysts, as well as endeavor to determine the molecular mechanism of the insulin's effect. Culture in media containing 1.7 rM insulin increased epiblast cell number (determined by Oct4 and Nanog co-expression), and proportion in day 6 blastocysts. The inhibition of phosphoinositide 3 kinase (PI3K) (via LY294002), an early second messenger of the insulin receptor, blocked this effect. The inhibition of glycogen synthase kinase 3 (GSK3) or p53, 2 s messengers inactivated by insulin signaling (via CT99021 or pifithrin-a, respectively), increased epiblast cell numbers. When active, GSK3 and p53 block the transcription of Nanog, which is important for maintaining pluripotency. A simultaneous inhibition of GSK3 and p53 had no synergistic effects on epiblast cell number. The induced activation of GSK3 and p53, via the inhibition of proteins responsible for their inactivation (PKA via H-89 and SIRT-1 via nicotinamide, respectively), blocked the insulin's effect on the epiblast.From our findings, we conclude that insulin increases epiblast cell number via the activation of PI3K, which ultimately inactivates GSK3 and p53. Furthermore, we suggest that the inclusion of insulin in culture media could be used as a strategy for increasing the efficiency with which the ESC lines can be derived from cultured embryos.

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Mouse embryonic stem cells and preimplantation embryos require signaling through the phosphatidylinositol 3‐kinase pathway to suppress apoptosis

Cited by 35 publications

References 53 publications

Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

Effects of oxygen tension and IGF-I on HIF-1α protein expression in mouse blastocysts

Insulin Increases Epiblast Cell Number of In Vitro Cultured Mouse Embryos via the PI3K/GSK3/p53 Pathway

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