Limits...
Msx homeobox genes critically regulate embryo implantation by controlling paracrine signaling between uterine stroma and epithelium.

Nallasamy S, Li Q, Bagchi MK, Bagchi IC - PLoS Genet. (2012)

Bottom Line: The mammalian Msx homeobox genes, Msx1 and Msx2, encode transcription factors that control organogenesis and tissue interactions during embryonic development.We observed overlapping expression of these factors in uterine epithelial and stromal compartments of pregnant mice prior to embryo implantation.Increased canonical Wnt signaling in the stromal cells activated β-catenin, stimulating the production of a subset of fibroblast growth factors (FGFs) in these cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America.

ABSTRACT
The mammalian Msx homeobox genes, Msx1 and Msx2, encode transcription factors that control organogenesis and tissue interactions during embryonic development. We observed overlapping expression of these factors in uterine epithelial and stromal compartments of pregnant mice prior to embryo implantation. Conditional ablation of both Msx1 and Msx2 in the uterus resulted in female infertility due to a failure in implantation. In these mutant mice (Msx1/2(d/d)), the uterine epithelium exhibited persistent proliferative activity and failed to attach to the embryos. Gene expression profiling of uterine epithelium and stroma of Msx1/2(d/d) mice revealed an elevated expression of several members of the Wnt gene family in the preimplantation uterus. Increased canonical Wnt signaling in the stromal cells activated β-catenin, stimulating the production of a subset of fibroblast growth factors (FGFs) in these cells. The secreted FGFs acted in a paracrine manner via the FGF receptors in the epithelium to promote epithelial proliferation, thereby preventing differentiation of this tissue and creating a non-receptive uterus refractory to implantation. Collectively, these findings delineate a unique signaling network, involving Msx1/2, Wnts, and FGFs, which operate in the uterus at the time of implantation to control the mesenchymal-epithelial dialogue critical for successful establishment of pregnancy.

Show MeSH

Related in: MedlinePlus

Enhanced ESR1 activity in the luminal epithelium of Msx1d/dMsx2d/d uteri.A. Uterine sections obtained from Msx1f/f Msx2f/f (left panel) and Msx1d/dMsx2d/d (right panel) mice on day 4 of pregnancy were subjected to IHC using antibodies against PGR (top panel, a and b), ESR1 (middle panel, c and d) and phospho-ESR1 (lower panel, e and f). B. Real-time PCR was performed to analyze the expression of E-regulated genes, lactotransferrin (Ltf), Clca3, lipocalin2 and Muc-1 in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Ck18 was used as internal control to normalize gene expression. The data are represented as the mean fold induction ± SEM, *p<0.05. C. Real-time PCR was performed to analyze the expression of P-regulated genes, Ihh, COUP-TF II, Hand2 and Hoxa10, in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Rplp0 or Ck18 was used as internal control to normalize gene expression.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3285581&req=5

pgen-1002500-g003: Enhanced ESR1 activity in the luminal epithelium of Msx1d/dMsx2d/d uteri.A. Uterine sections obtained from Msx1f/f Msx2f/f (left panel) and Msx1d/dMsx2d/d (right panel) mice on day 4 of pregnancy were subjected to IHC using antibodies against PGR (top panel, a and b), ESR1 (middle panel, c and d) and phospho-ESR1 (lower panel, e and f). B. Real-time PCR was performed to analyze the expression of E-regulated genes, lactotransferrin (Ltf), Clca3, lipocalin2 and Muc-1 in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Ck18 was used as internal control to normalize gene expression. The data are represented as the mean fold induction ± SEM, *p<0.05. C. Real-time PCR was performed to analyze the expression of P-regulated genes, Ihh, COUP-TF II, Hand2 and Hoxa10, in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Rplp0 or Ck18 was used as internal control to normalize gene expression.

Mentions: While Msx1f/fMsx2f/f mice exhibited normal litter size and pregnancy rates, the Msx1d/dMsx2d/d females failed to become pregnant when mated with wild-type males. However, copulatory plugs were observed upon mating, indicating normal mating behavior. To investigate the cause of infertility in Msx1d/dMsx2d/d females, we examined their ovarian functions by inducing superovulation. Prepubertal Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice were treated with a regimen of gonadotropin hormones as described in Materials and Methods. We observed that, upon gonadotropin stimulation, the number of eggs produced by Msx1d/dMsx2d/d was comparable to that produced by the Msx1f/fMsx2f/f females (Figure S3A), indicating that ovulation is not affected in the absence of Msx1 and Msx2. To further examine the ovulation and fertilization in these mice under normal physiological conditions, blastocysts were recovered from uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy prior to implantation. Once again, no significant difference was found in either the number or the morphology of the embryos recovered from Msx1f/fMsx2f/f and Msx1d/dMsx2d/d uteri (Figure S3B and Figure 3C). In further support of normal ovarian activity, the serum levels of progesterone and estrogen were comparable in Msx1f/fMsx2f/f and Msx1d/dMsx2d/d females on day 4 of pregnancy (Figure S3D and Figure S3E). Collectively, these results suggested that the infertility of Msx1d/dMsx2d/d females is not due to impairment in the hypothalamic-pituitary-ovarian axis or lack of fertilization, but is likely due to defective implantation or pregnancy failure following implantation.


Msx homeobox genes critically regulate embryo implantation by controlling paracrine signaling between uterine stroma and epithelium.

Nallasamy S, Li Q, Bagchi MK, Bagchi IC - PLoS Genet. (2012)

Enhanced ESR1 activity in the luminal epithelium of Msx1d/dMsx2d/d uteri.A. Uterine sections obtained from Msx1f/f Msx2f/f (left panel) and Msx1d/dMsx2d/d (right panel) mice on day 4 of pregnancy were subjected to IHC using antibodies against PGR (top panel, a and b), ESR1 (middle panel, c and d) and phospho-ESR1 (lower panel, e and f). B. Real-time PCR was performed to analyze the expression of E-regulated genes, lactotransferrin (Ltf), Clca3, lipocalin2 and Muc-1 in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Ck18 was used as internal control to normalize gene expression. The data are represented as the mean fold induction ± SEM, *p<0.05. C. Real-time PCR was performed to analyze the expression of P-regulated genes, Ihh, COUP-TF II, Hand2 and Hoxa10, in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Rplp0 or Ck18 was used as internal control to normalize gene expression.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3285581&req=5

pgen-1002500-g003: Enhanced ESR1 activity in the luminal epithelium of Msx1d/dMsx2d/d uteri.A. Uterine sections obtained from Msx1f/f Msx2f/f (left panel) and Msx1d/dMsx2d/d (right panel) mice on day 4 of pregnancy were subjected to IHC using antibodies against PGR (top panel, a and b), ESR1 (middle panel, c and d) and phospho-ESR1 (lower panel, e and f). B. Real-time PCR was performed to analyze the expression of E-regulated genes, lactotransferrin (Ltf), Clca3, lipocalin2 and Muc-1 in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Ck18 was used as internal control to normalize gene expression. The data are represented as the mean fold induction ± SEM, *p<0.05. C. Real-time PCR was performed to analyze the expression of P-regulated genes, Ihh, COUP-TF II, Hand2 and Hoxa10, in uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy. The level of Rplp0 or Ck18 was used as internal control to normalize gene expression.
Mentions: While Msx1f/fMsx2f/f mice exhibited normal litter size and pregnancy rates, the Msx1d/dMsx2d/d females failed to become pregnant when mated with wild-type males. However, copulatory plugs were observed upon mating, indicating normal mating behavior. To investigate the cause of infertility in Msx1d/dMsx2d/d females, we examined their ovarian functions by inducing superovulation. Prepubertal Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice were treated with a regimen of gonadotropin hormones as described in Materials and Methods. We observed that, upon gonadotropin stimulation, the number of eggs produced by Msx1d/dMsx2d/d was comparable to that produced by the Msx1f/fMsx2f/f females (Figure S3A), indicating that ovulation is not affected in the absence of Msx1 and Msx2. To further examine the ovulation and fertilization in these mice under normal physiological conditions, blastocysts were recovered from uteri of Msx1f/fMsx2f/f and Msx1d/dMsx2d/d mice on day 4 of pregnancy prior to implantation. Once again, no significant difference was found in either the number or the morphology of the embryos recovered from Msx1f/fMsx2f/f and Msx1d/dMsx2d/d uteri (Figure S3B and Figure 3C). In further support of normal ovarian activity, the serum levels of progesterone and estrogen were comparable in Msx1f/fMsx2f/f and Msx1d/dMsx2d/d females on day 4 of pregnancy (Figure S3D and Figure S3E). Collectively, these results suggested that the infertility of Msx1d/dMsx2d/d females is not due to impairment in the hypothalamic-pituitary-ovarian axis or lack of fertilization, but is likely due to defective implantation or pregnancy failure following implantation.

Bottom Line: The mammalian Msx homeobox genes, Msx1 and Msx2, encode transcription factors that control organogenesis and tissue interactions during embryonic development.We observed overlapping expression of these factors in uterine epithelial and stromal compartments of pregnant mice prior to embryo implantation.Increased canonical Wnt signaling in the stromal cells activated β-catenin, stimulating the production of a subset of fibroblast growth factors (FGFs) in these cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, Illinois, United States of America.

ABSTRACT
The mammalian Msx homeobox genes, Msx1 and Msx2, encode transcription factors that control organogenesis and tissue interactions during embryonic development. We observed overlapping expression of these factors in uterine epithelial and stromal compartments of pregnant mice prior to embryo implantation. Conditional ablation of both Msx1 and Msx2 in the uterus resulted in female infertility due to a failure in implantation. In these mutant mice (Msx1/2(d/d)), the uterine epithelium exhibited persistent proliferative activity and failed to attach to the embryos. Gene expression profiling of uterine epithelium and stroma of Msx1/2(d/d) mice revealed an elevated expression of several members of the Wnt gene family in the preimplantation uterus. Increased canonical Wnt signaling in the stromal cells activated β-catenin, stimulating the production of a subset of fibroblast growth factors (FGFs) in these cells. The secreted FGFs acted in a paracrine manner via the FGF receptors in the epithelium to promote epithelial proliferation, thereby preventing differentiation of this tissue and creating a non-receptive uterus refractory to implantation. Collectively, these findings delineate a unique signaling network, involving Msx1/2, Wnts, and FGFs, which operate in the uterus at the time of implantation to control the mesenchymal-epithelial dialogue critical for successful establishment of pregnancy.

Show MeSH
Related in: MedlinePlus