mTORC1/2 signaling is downregulated by amino acid-free culture of mouse preimplantation embryos and is only partially restored by amino acid readdition
| Autor: | Michael B. Morris, Margot L. Day, Radu C. Zamfirescu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Male Time Factors Physiology P70-S6 Kinase 1 Cell Cycle Proteins mTORC1 Mechanistic Target of Rapamycin Complex 2 Mechanistic Target of Rapamycin Complex 1 Embryo Culture Techniques 03 medical and health sciences Mice 0302 clinical medicine Pregnancy Animals Amino Acids Phosphorylation Autocrine signalling Protein kinase B PI3K/AKT/mTOR pathway Adaptor Proteins Signal Transducing Ribosomal Protein S6 Chemistry Ribosomal Protein S6 Kinases 70-kDa Embryo culture Cell Biology Cell biology Culture Media 030104 developmental biology Blastocyst 030220 oncology & carcinogenesis Ribosomal protein s6 Female biological phenomena cell phenomena and immunity Phosphatidylinositol 3-Kinase Proto-Oncogene Proteins c-akt Signal Transduction |
| Zdroj: | American journal of physiology. Cell physiology. 320(1) |
| ISSN: | 1522-1563 |
| Popis: | Development of the mammalian preimplantation embryo is influenced by autocrine/paracrine factors and the availability of nutrients. Deficiencies of these during in vitro culture reduce the success of assisted reproductive technologies. The mechanistic target of rapamycin complex 1 (mTORC1) pathway integrates external and internal signals, including those by amino acids (AAs), to promote normal preimplantation development. For this reason, AAs are often included in embryo culture media. In this study, we examined how withdrawal and addition of AAs to culture media modulate mTORC1 pathway activity compared with its activity in mouse embryos developed in vivo. Phosphorylation of signaling components downstream of mTORC1, namely, p70 ribosomal protein S6 kinase (p70S6K), ribosomal protein S6, and 4E binding protein 1 (4E-BP1), and that of protein kinase B (Akt), which lies upstream of mTORC1, changed significantly across stages of embryos developed in vivo. For freshly isolated blastocysts placed in vitro, the absence of AAs in the culture medium, even for a few hours, decreased mTORC1 signaling, which could only be partially restored by their addition. Long-term culture of early embryos to blastocysts in the absence of AAs decreased mTORC1 signaling to a greater extent and again this could only be partially restored by their inclusion. This failure to fully restore is probably due to decreased phosphatidylinositol 3-kinase (PI3K)/Akt/mTORC2 signaling in culture, as indicated by decreased P-AktS473. mTORC2 lies upstream of mTORC1 and is insensitive to AAs, and its reduced activity probably results from loss of maternal/autocrine factors. These data highlight reduced mTORC1/2 signaling activity correlating with compromised development in vitro and show that the addition of AAs can only partially offset these effects. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|