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In vitro fertilization and embryo culture strongly impact the placental transcriptome in the mouse model.

Fauque P, Mondon F, Letourneur F, Ripoche MA, Journot L, Barbaux S, Dandolo L, Patrat C, Wolf JP, Jouannet P, Jammes H, Vaiman D - PLoS ONE (2010)

Bottom Line: Imprinted genes were modified similarly to the X.Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions.Our results highlight the importance of studying human placentas from ART.

View Article: PubMed Central - PubMed

Affiliation: Service d'Histologie-Embryologie, Biologie de la Reproduction, Hôpital Cochin, Paris, France. patricia.fauque@cch.aphp.fr

ABSTRACT

Background: Assisted Reproductive Technologies (ART) are increasingly used in humans; however, their impact is now questioned. At blastocyst stage, the trophectoderm is directly in contact with an artificial medium environment, which can impact placental development. This study was designed to carry out an in-depth analysis of the placental transcriptome after ART in mice.

Methodology/principal findings: Blastocysts were transferred either (1) after in vivo fertilization and development (control group) or (2) after in vitro fertilization and embryo culture. Placentas were then analyzed at E10.5. Six percent of transcripts were altered at the two-fold threshold in placentas of manipulated embryos, 2/3 of transcripts being down-regulated. Strikingly, the X-chromosome harbors 11% of altered genes, 2/3 being induced. Imprinted genes were modified similarly to the X. Promoter composition analysis indicates that FOXA transcription factors may be involved in the transcriptional deregulations.

Conclusions: For the first time, our study shows that in vitro fertilization associated with embryo culture strongly modify the placental expression profile, long after embryo manipulations, meaning that the stress of artificial environment is memorized after implantation. Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions. Our results highlight the importance of studying human placentas from ART.

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Magnitude of induced (up-regulated more than two-fold), repressed (down-regulated more than two fold) and unchanged genes located on the X-chromosome (A) and imprinted genes (B) compared to the complete set of genes in IVF G1/G2 samples (P<0.0001, χ2-test).
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pone-0009218-g005: Magnitude of induced (up-regulated more than two-fold), repressed (down-regulated more than two fold) and unchanged genes located on the X-chromosome (A) and imprinted genes (B) compared to the complete set of genes in IVF G1/G2 samples (P<0.0001, χ2-test).

Mentions: We attempted to analyze gene expression modifications according to the chromosome localization. We used the information available from the Affymetrix database to sort the data per chromosome, and we performed a Chi2 test to compare the number of induced/repressed/unmodified genes (at the two-fold threshold) between each chromosome and the rest of the genome (See the Supplemental Table S1). A correction was then applied in order to take into account the multiple testing; with this correction the statistical test was considered significant if below 0.0025. Using this threshold, only the X chromosome was different from the rest of the genome (Figure 5A, χ2-test  = 2.8 10−30). This skewed proportion was essentially due to the striking abundance of up-regulated genes located on this chromosome (7.4% vs 2.6% for the rest of the genome). By contrast, repressed genes were not different (3.2% vs 3.6% for the rest of the genome). The effect on non pseudoautosomal X genes was apparently not linked to the distance from the X inactivation center (Xic) (Figure 6). This effect was not due to a skewed representation of male and female embryos in the different RNA pools that were used. Since at this early stage, sex determination is starting (Sry is expressed at 10.5 dpc, the possible skews in representation were followed using the expression levels of Y-specific markers such as UtY, which were not different between the groups. Moreover, a skewed representation of male and female embryos would have the same consequences on induced and repressed genes, which is not what we observed. Thus, the X-specific transcriptome modifications described here appear genuine.


In vitro fertilization and embryo culture strongly impact the placental transcriptome in the mouse model.

Fauque P, Mondon F, Letourneur F, Ripoche MA, Journot L, Barbaux S, Dandolo L, Patrat C, Wolf JP, Jouannet P, Jammes H, Vaiman D - PLoS ONE (2010)

Magnitude of induced (up-regulated more than two-fold), repressed (down-regulated more than two fold) and unchanged genes located on the X-chromosome (A) and imprinted genes (B) compared to the complete set of genes in IVF G1/G2 samples (P<0.0001, χ2-test).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2821408&req=5

pone-0009218-g005: Magnitude of induced (up-regulated more than two-fold), repressed (down-regulated more than two fold) and unchanged genes located on the X-chromosome (A) and imprinted genes (B) compared to the complete set of genes in IVF G1/G2 samples (P<0.0001, χ2-test).
Mentions: We attempted to analyze gene expression modifications according to the chromosome localization. We used the information available from the Affymetrix database to sort the data per chromosome, and we performed a Chi2 test to compare the number of induced/repressed/unmodified genes (at the two-fold threshold) between each chromosome and the rest of the genome (See the Supplemental Table S1). A correction was then applied in order to take into account the multiple testing; with this correction the statistical test was considered significant if below 0.0025. Using this threshold, only the X chromosome was different from the rest of the genome (Figure 5A, χ2-test  = 2.8 10−30). This skewed proportion was essentially due to the striking abundance of up-regulated genes located on this chromosome (7.4% vs 2.6% for the rest of the genome). By contrast, repressed genes were not different (3.2% vs 3.6% for the rest of the genome). The effect on non pseudoautosomal X genes was apparently not linked to the distance from the X inactivation center (Xic) (Figure 6). This effect was not due to a skewed representation of male and female embryos in the different RNA pools that were used. Since at this early stage, sex determination is starting (Sry is expressed at 10.5 dpc, the possible skews in representation were followed using the expression levels of Y-specific markers such as UtY, which were not different between the groups. Moreover, a skewed representation of male and female embryos would have the same consequences on induced and repressed genes, which is not what we observed. Thus, the X-specific transcriptome modifications described here appear genuine.

Bottom Line: Imprinted genes were modified similarly to the X.Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions.Our results highlight the importance of studying human placentas from ART.

View Article: PubMed Central - PubMed

Affiliation: Service d'Histologie-Embryologie, Biologie de la Reproduction, Hôpital Cochin, Paris, France. patricia.fauque@cch.aphp.fr

ABSTRACT

Background: Assisted Reproductive Technologies (ART) are increasingly used in humans; however, their impact is now questioned. At blastocyst stage, the trophectoderm is directly in contact with an artificial medium environment, which can impact placental development. This study was designed to carry out an in-depth analysis of the placental transcriptome after ART in mice.

Methodology/principal findings: Blastocysts were transferred either (1) after in vivo fertilization and development (control group) or (2) after in vitro fertilization and embryo culture. Placentas were then analyzed at E10.5. Six percent of transcripts were altered at the two-fold threshold in placentas of manipulated embryos, 2/3 of transcripts being down-regulated. Strikingly, the X-chromosome harbors 11% of altered genes, 2/3 being induced. Imprinted genes were modified similarly to the X. Promoter composition analysis indicates that FOXA transcription factors may be involved in the transcriptional deregulations.

Conclusions: For the first time, our study shows that in vitro fertilization associated with embryo culture strongly modify the placental expression profile, long after embryo manipulations, meaning that the stress of artificial environment is memorized after implantation. Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions. Our results highlight the importance of studying human placentas from ART.

Show MeSH