SMAD Signaling Is Required for Structural Integrity of the Female Reproductive Tract and Uterine Function During Early Pregnancy in Mice.

Pregnancy is a complex physiological process tightly controlled by the interplay among hormones, morphogens, transcription factors, and signaling pathways. Although recent studies using genetically engineered mouse models have revealed that ligands and receptors of transforming growth factor beta (TGFbeta) and bone morphogenetic protein (BMP) signaling pathways are essential for multiple reproductive events during pregnancy, the functional role of SMAD transcription factors, which serve as the canonical signaling platform for the TGFbeta/BMP pathways, in the oviduct and uterus is undefined. Here, we used a mouse model containing triple conditional deletion of the BMP receptor signaling Smads (Smad1 and Smad5) and Smad4, the central mediator of both TGFbeta and BMP signaling, to investigate the role of the SMADs in reproductive tract structure and function in cells from the Amhr2 lineage. Unlike the respective single- or double-knockouts, female Smad1(flox/flox) Smad5(flox/flox) Smad4(flox/flox) Amhr2(cre/+)conditional knockout (i.e., Smad1/5/4-Amhr2-cre KO) mice are sterile. We discovered that Smad1/5/4-Amhr2-cre KO females have malformed oviducts that subsequently develop oviductal diverticuli. These oviducts showed dysregulation of multiple genes essential for oviduct and smooth muscle development. In addition, uteri from Smad1/5/4-Amhr2-cre KO females exhibit multiple defects in stroma, epithelium, and smooth muscle layers and fail to assemble a closed uterine lumen upon embryo implantation, with defective uterine decidualization that led to pregnancy loss at early to mid-gestation. Taken together, our study uncovers a new role for the SMAD transcription factors in maintaining the structural and functional integrity of oviduct and uterus, required for establishment and maintenance of pregnancy.

Constitutive Notch Signaling Causes Abnormal Development of the Oviducts, Abnormal Angiogenesis, and Cyst Formation in Mouse Female Reproductive Tract.

The Notch signaling pathway is critical for the differentiation of many tissues and organs in the embryo. To study the consequences of Notch1 gain-of-function signaling on female reproductive tract development, we used a cre-loxP strategy and Amhr2-cre transgene to generate mice with conditionally activated Notch1 (Rosa(Notch1)). The Amhr2-cre transgene is expressed in the mesenchyme of developing female reproductive tract and in granulosa cells in the ovary. Double transgenic Amhr2-cre, Rosa(Notch1) females were infertile, whereas control Rosa(Notch1) mice had normal fertility. All female reproductive organs in mutants showed hemorrhaging of blood vessels progressing with age. The mutant oviducts did not develop coiling, and were instead looped around the ovary. There were multiple blockages in the lumen along the oviduct length, creating a barrier for sperm or oocyte passage. Mutant females demonstrated inflamed uteri with increased vascularization and an influx of inflammatory cells. Additionally, older females developed ovarian, oviductal, and uterine cysts. The significant change in gene expression was detected in the mutant oviduct expression of Wnt4, essential for female reproductive tract development. Similar oviductal phenotypes have been detected previously in mice with activated Smo and in beta-catenin, Wnt4, Wnt7a, and Dicer conditional knockouts, indicating a common regulatory pathway disrupted by these genetic abnormalities.

Reproductive and developmental effects of transovarian exposure to o,p'-DDT in Japanese quails.

Avian species have the possible risk of embryonic exposure to persistent, lipophilic environmental contaminants, such as dichlorodiphenyltrichloroethane (DDT), by transfer of chemicals accumulated in mother birds to eggs. To model developmental and reproductive disorders of wild birds living in contaminated areas, we exposed Japanese quails in ovo to o,p'-DDT prior to incubation. A positive estrogenic substance diethylstilbestrol (DES; 1 and 10 ng/g of egg) and o,p'-DDT (1-100 microg/g of egg) were injected into the yolk before incubation. Treatment with o,p'-DDT (10 or 100 microg/g) but not with DES significantly reduced the hatchability of eggs. After sexual maturation, o,p'-DDT affected eggshell formation in female quails but had little influence on laying; high doses of o,p'-DDT significantly reduced eggshell strength, shell weight, and shell thickness, and several females treated with 100 microg o,p'-DDT/g laid eggs lacking shells. Diethylstilbestrol decreased egg production itself but had little effect on the eggshell. Both o,p'-DDT and DES caused dose-dependent shortening of the left oviduct and abnormal development of the right oviduct in females, while testis asymmetry was observed in males treated with a high dose of DES. In the uterus of the oviduct, the mRNAs for calcium-regulating factors osteopontin and calbindin D28K were reduced by both treatments, particularly that with o,p'-DDT. The results indicated that transovarian exposure to o,p'-DDT could bring about population declines in avian species through loss of fecundity caused by depression of hatchability and dysfunction of the reproductive tract.

Hereditary persistent right oviduct in the chicken PNP/DO line.

Hereditary, persistent, right oviduct manifested in an inbred line (PNP/DO line) from the Fayoumi breed of chickens was investigated for form of expression and mode of inheritance. Females in the PNP/DO line have varying lengths of elongated right oviducts, besides the normal left ovary, and oviducts that generally possess, irrespective of their total length, regions similar to those normally observed in a left oviduct. Observations of embryos indicated that the existence of right oviduct in this line could be attributed to the slow regression of right Müllerian duct during the embryonic stage, and left-right asymmetry in female genital system is intrinsic in this line. Intracrosses of the PNP/DO line produced 93% of female embryos with persistent right Müllerian ducts at the next generation, and reciprocal crosses of the PNP/DO line and control strains produced 5 and 30% of female embryos with persistent right Müllerian ducts in the F1 and N2 generations, respectively. Mating results suggested that this mutant trait is controlled by two pairs of autosomal recessive genes with major effects and numerous loci that have minor effects. Thus, expression of this trait is due to the interaction of major loci and the background genotype.

Sexually dimorphic development of the mammalian reproductive tract requires Wnt-7a.

An important feature of mammalian development is the generation of sexually dimorphic reproductive tracts from the Müllerian and Wolffian ducts. In females, Müllerian ducts develop into the oviduct, uterus, cervix and upper vagina, whereas Wolffian ducts regress. In males, testosterone promotes differentiation of Wolffian ducts into the epididymis, vas deferens and seminal vesicle. The Sertoli cells of the testes produce Müllerian-inhibiting substance, which stimulates Müllerian duct regression in males. The receptor for Müllerian-inhibiting substance is expressed by mesenchymal cells underlying the Müllerian duct that are thought to mediate regression of the duct. Mutations that inactivate either Müllerian-inhibiting substance or its receptor allow development of the female reproductive tract in males. These pseudohermaphrodites are frequently infertile because sperm passage is blocked by the presence of the female reproductive system. Here we show that male mice lacking the signalling molecule Wnt-7a fail to undergo regression of the Müllerian duct as a result of the absence of the receptor for Müllerian-inhibiting substance. Wnt7a-deficient females are infertile because of abnormal development of the oviduct and uterus, both of which are Müllerian duct derivatives. Therefore, we propose that signalling by Wnt-7a allows sexually dimorphic development of the Müllerian ducts.

[Deficiencies of the müllerian ducts induced by norethindrone in the female chick embryo]. / Sur les déficiences des canaux de Müller induites par la noréthindrone chez l'embryon femelle de poulet.

Norethindrone produces two effects on müllerian ducts (MD) of female chick embryos. It induces the loss of the lower end of both ducts, as a result of a stop in their development, before 8 days. After 12 days NET causes regressions of the upper part of the MD particularly of the oviduct. NET like estrogens are the only known substances which present these both properties.

Effect of embryonic treatment with oestradiol benzoate on reproductive morphology, ovulation and oviposition and plasma LH concentrations in female quail (Coturnix coturnix japonica).

Quail eggs were injected on Day 10 of incubation with 0, 5, 10, 20 or 40 micrograms oestradiol benzoate. Females hatching from these eggs were reared on a 16L: 8D photoperiod and egg laying was recorded. Blood samples were taken at 37, 40, 43, 46, 49, 52, 55, 58 or 61 days of age and LH concentrations were measured by a double-antibody radioimmunoassay. Birds were killed at 61 days of age; ovaries and oviducts were weighed and examined. Egg laying was greatly reduced by oestradiol benzoate treatment, but for birds that did lay, age at first oviposition was normal. LH levels were not affected by oestradiol benzoate treatment, and were highest at 40 and 49 days of age. Oestradiol benzoate had no effect on ovarian weight, number of follicles with diameter greater than 1 cm, or number of post-ovulatory follicles. Oestradiol benzoate had a dose-related effect on the likelihood that females would have two oviducts, and for those females that had retained the right oviduct, the left oviduct was smaller than normal. Oestradiol benzoate-treated females were more likely to have ovulated yolks in the body cavity. Embryonic treatment with oestradiol benzoate therefore appears to inhibit egg laying by causing oviduct abnormalities, rather than by (as happens in mammals) inhibiting ovulation.

Developmentally arrested oviduct: a structural and functional defect in mice following prenatal exposure to diethylstilbestrol.

To determine the effects of exposure to diethylstilbestrol (DES) on the developing oviduct, timed pregnant CD-1 mice were treated with DES (10-100 micrograms/kg subcutaneous) on days 9-16 of gestation. Prenatal DES-exposed and age-matched control mice were sacrificed from day 16 of gestation to 15 weeks of age and oviductal development was compared. Following prenatal exposure to DES (100 micrograms/kg), the oviduct at all ages examined was uncoiled and shorter, closely adherent to and wrapped around the ovary in an anatomical configuration similar to the fetal mouse. In addition, the demarcation between the oviduct and uterus was not readily apparent. Histological changes in the DES (100 micrograms/kg) oviduct as compared with control at 10-15 weeks of age included a proliferation of columnar epithelium lining the lumen with gland formation extending into the underlying stroma, absence of or a reduced amount of fimbrial tissue, increased thickness of the muscular wall, and inflammatory cell infiltration. Also, as a functional test of uterotubal junction integrity, Coomassie Blue dye was injected into the uterus. The control uterotubal junction confined the fluid to the uterus. In 80% and 100% of the animals exposed prenatally to DES (10 and 100 micrograms/kg, respectively), independent of the extent of the gross abnormality, the dye readily flowed into the oviduct and filled the ovarian bursa. We conclude that prenatal DES exposure can alter fetal development of the mouse oviduct, resulting in an apparent developmental arrest and functional disruption of the integrity of the uterotubal junction. The fetal like configuration of the ovary, oviduct, and uterus suggests the term developmentally arrested oviduct (DAO).

Persistent right oviduct in ring-necked pheasant.

1. A right oviduct, approximately two-thirds the length of the left oviduct, and with a separate opening into the cloaca was observed in a female Ring-necked pheasant. 2. It is suggested that interference of the synthesis of Müllerian inhibiting factor from the gonads may have allowed its development.