Estimation of Isotonic Point of Incubation Medium For Two-Cell Mouse Embryo

Pogorelova, M. A.; Голиченков, В. А.; Pogorelova, V. N.; Kornienko, E. V.; Panait, A. I.; Pogorelov, A. G.

doi:10.1007/s10517-011-1474-x

Cited by 5 publications

(5 citation statements)

References 10 publications

(22 reference statements)

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“…Although we used 370 mOsM medium here to obtain a maximum difference between development with and without glycine, a significant decrease in development was evident between 310 and 330 mOsM. This is nearer to the in vivo osmolarity of oviductal fluid, which has been measured to be ~300 mOsM [42][43][44], although calculations have indicated it may reach as high as 350 mOsM during early preimplantation embryo development [3]. This is supportive of a possible role for glycine in vivo, since relatively small increases in oviductal fluid osmolarity would have an impact on embryo development even at the lower values proposed for oviductal fluid.…”

Section: Discussionmentioning

confidence: 84%

Oocyte-Specific Deletion of Slc6a9 Encoding the GLYT1 Glycine Transporter Eliminates Glycine Transport in Mouse Preimplantation Embryos and Their Ability to Counter Hypertonic Stress

Tscherner,

McClatchie,

Kaboba

et al. 2023

Cells

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Early preimplantation mouse embryos are sensitive to increased osmolarity, which can block their development. To overcome this, they accumulate organic osmolytes to maintain cell volume. The main organic osmolyte used by early mouse embryos is glycine. Glycine is transported during the mature egg and 1-cell to 4-cell embryo stages by a transporter identified as GLYT1, encoded by the Slc6a9 gene. Here, we have produced an oocyte-specific knockout of Slc6a9 by crossing mice that have a segment of the gene flanked by LoxP elements with transgenic mice expressing iCre driven by the oocyte-specific Gdf9 promoter. Slc6a9 null oocytes failed to develop glycine transport activity during meiotic maturation. However, females with these oocytes were fertile. When enclosed in their cumulus-oocyte complex, Slc6a9 null oocytes could accumulate glycine via GLYT1 transport in their coupled cumulus cells, which may support female fertility in vivo. In vitro, embryos derived from Slc6a9 null oocytes displayed a clear phenotype. While glycine rescued complete preimplantation development of wild type embryos from increased osmolarity, embryos derived from null oocytes failed to develop past the 2-cell stage even with glycine. Thus, Slc6a9 is required for glycine transport and protection against increased osmolarity in mouse eggs and early embryos.

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Section: Discussionmentioning

confidence: 84%

Oocyte-Specific Deletion of Slc6a9 Encoding the GLYT1 Glycine Transporter Eliminates Glycine Transport in Mouse Preimplantation Embryos and Their Ability to Counter Hypertonic Stress

Tscherner,

McClatchie,

Kaboba

et al. 2023

Cells

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show abstract

“…It was concluded that this fluid has an osmolality of about 290-300 mOsmol/ kg based, in part, on the osmolality at which zygotes did not shrink or swell beginning 1.8 min after they were placed in media of various osmolalities between 200 and 400 mOsmol/ kg. The same approach for two-cell embryos yielded a similar conclusion (Collins and Baltz, 1999;Pogorelova et al, 2011). Not considered, however, were initial changes in zygote and embryo volume from when they were in oviductal fluid (e.g., Figure 2 in Collins and Baltz, 1999) to when volumes were measured in media 1.8 min later ( Figure 3 in Collins and Baltz, 1999).…”

Section: Attempts To Measure Oviductal Fluid Osmolality May Have Expomentioning

confidence: 78%

“…Perhaps more importantly, when glycine is present in the medium, it protects against one-cell embryo shrinkage even in medium of 350 mOsmol/kg (Steeves et al, 2003). Hence, most of the data in Figure 1, and data reported elsewhere (Collins and Baltz, 1999;Pogorelova et al, 2011), were collected under non-physiological conditions (in particular, in the absence of extracellular glycine in the medium).…”

Section: Attempts To Measure Oviductal Fluid Osmolality May Have Expomentioning

confidence: 99%

Perspective: One-Cell and Cleavage-Stage Mouse Embryos Thrive in Hyperosmotic Oviductal Fluid Through Expression of a Glycine Neurotransmitter Transporter and a Glycine-Gated Chloride Channel: Clinical and Transgenerational Implications

Winkle

2020

Front. Physiol.

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The osmolality of mouse oviductal fluid ranges from about 300 mOsmol/kg in the ampulla 0–3 h post coitus (h p.c.) to more than 350 mOsmol/kg in the isthmus 34–36 h p.c. Thus, it has been surprising to find that development of one-cell and cleavage-stage mouse embryos arrests in vitro in media exceeding 300 mOsmol/kg, and they develop best in unphysiological, hypotonic media. The glycine concentration in oviductal fluid can, however, rescue development in hypertonic media, so physiological conditions in vivo and in vitro likely work together to foster embryo well-being. Glycine acts on one-cell and cleavage-stage mouse embryos through the glycine-gated chloride channel, GLRA4, and uptake via the glycine neurotransmitter transporter, GLYT1. Since these processes lead to further signaling in neurons, the presence and function of such signaling in preimplantation embryos also should be investigated. The more we know about the interactions of physiological processes and conditions in vivo, the better we would be able to reproduce them in vitro. Such improvements in assisted reproductive technology (ART) could improve patient outcomes for IVF and potentially help prevent unwanted developmental abnormalities in early embryos, which might include undesirable epigenetic DNA and histone modifications. These epigenetic modifications may lead to transgenerational adult disorders such as metabolic syndrome and related conditions.

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“…It was possible that the lower osmolarity of the media that supported complete preimplantation development could have been explained by their mimicking a low osmolarity environment of early embryos in the oviduct in vivo. However, measurements of the osmolarity of oviductal fluid instead showed that it was similar to the osmolarity of the fluids surrounding most cells and to that of culture media in which embryo development was blocked, with a range of about 290–310 mOsM for mouse oviductal fluid (Collins & Baltz, 1999; Fiorenza et al, 2004; Pogorelova et al, 2011), a similar range in rat (Waring, 1976), and somewhat higher at 320 mOsM in pig (Li et al, 2007). Indeed, these values may actually be low.…”

Section: Role Of Osmolarity In Developmental Arrest Of Early Embryosmentioning

confidence: 99%

Initiation of cell volume regulation and unique cell volume regulatory mechanisms in mammalian oocytes and embryos

Tscherner

Macaulay

Ortman

et al. 2021

Journal Cellular Physiology

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The period beginning with the signal for ovulation, when a fully‐grown oocyte progresses through meiosis to become a mature egg that is fertilized and develops as a preimplantation embryo, is crucial for healthy development. The early preimplantation embryo is unusually sensitive to cell volume perturbations, with even moderate decreases in volume or dysregulation of volume‐regulatory mechanisms resulting in developmental arrest. To prevent this, early embryos possess mechanisms of cell volume control that are apparently unique to them. These rely on the accumulation of glycine and betaine (N, N, N‐trimethylglycine) as organic osmolytes—compounds that can provide intracellular osmotic support without the deleterious effects of inorganic ions. Preimplantation embryos also have the same mechanisms as somatic cells that mediate rapid responses to deviations in cell volume, which rely on inorganic ion transport. Both the unique, embryo‐specific mechanisms that use glycine and betaine and the inorganic ion‐dependent mechanisms undergo major changes during meiotic maturation and preimplantation development. The most profound changes occur immediately after ovulation is triggered. Before this, oocytes cannot regulate their volume, since they are strongly attached to their rigid extracellular matrix shell, the zona pellucida. After ovulation is triggered, the oocyte detaches from the zona pellucida and first becomes capable of independent volume regulation. A complex set of developmental changes in each cell volume‐regulatory mechanism continues through egg maturation and preimplantation development. The unique cell volume‐regulatory mechanisms in eggs and preimplantation embryos and the developmental changes they undergo appear critical for normal healthy embryo development.

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Estimation of Isotonic Point of Incubation Medium For Two-Cell Mouse Embryo

Cited by 5 publications

References 10 publications

Oocyte-Specific Deletion of Slc6a9 Encoding the GLYT1 Glycine Transporter Eliminates Glycine Transport in Mouse Preimplantation Embryos and Their Ability to Counter Hypertonic Stress

Oocyte-Specific Deletion of Slc6a9 Encoding the GLYT1 Glycine Transporter Eliminates Glycine Transport in Mouse Preimplantation Embryos and Their Ability to Counter Hypertonic Stress

Perspective: One-Cell and Cleavage-Stage Mouse Embryos Thrive in Hyperosmotic Oviductal Fluid Through Expression of a Glycine Neurotransmitter Transporter and a Glycine-Gated Chloride Channel: Clinical and Transgenerational Implications

Initiation of cell volume regulation and unique cell volume regulatory mechanisms in mammalian oocytes and embryos

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