Targeted ablation ofWnt4andWnt5ain Müllerian duct mesenchyme impedes endometrial gland development and causes partial Müllerian agenesis†

Abstract

Both Wnt4 and Wnt5a have well-established roles in the embryonic development of the female reproductive tract, as well as in implantation, decidualization and ovarian function in adult mice. Although these roles appear to overlap, whether Wnt5a and Wnt4 are functionally redundant in these tissues has not been determined. Here, we addressed this by concomitantly inactivating Wnt4 and Wnt5a in the Müllerian mesenchyme and in ovarian granulosa cells by crossing mice bearing floxed alleles to the Amhr2cre strain. Whereas fertility was reduced by ∼50% in Wnt4flox/flox; Amhr2cre/+ and Wnt5aflox/flox; Amhr2cre/+ females, Wnt4flox/flox; Wnt5aflox/flox; Amhr2cre/+ mice were either nearly or completely sterile. Loss of fertility was not due to an ovarian defect, as serum ovarian hormone levels, follicle counts and ovulation rates were comparable to controls. Conversely, the uterus was abnormal in Wnt4flox/flox; Wnt5aflox/flox; Amhr2cre/+ mice, with thin myometrial and stromal layers, frequent fibrosis and a >90% reduction in numbers of uterine glands, suggesting redundant or additive roles of Wnt4 and Wnt5a in uterine adenogenesis. Loss of fertility in Wnt4flox/flox; Wnt5aflox/flox; Amhr2cre/+ mice was attributed to defects in decidualization, implantation and placental development, the severity of which were proportional to the extent of gland loss. Furthermore, a third of Wnt4flox/flox; Wnt5aflox/flox; Amhr2cre/+ females had a partial agenesis of Müllerian duct-derived structures (anterior vagina and cervix, or a partial or complete uterine horn), but with normal oviducts and ovaries. Together, our results suggest that Wnt4 and Wnt5a play redundant roles in the development of the female reproductive tract, and may provide insight into the etiology of certain cases of Müllerian agenesis in women.

Lats1 and Lats2 are required for the maintenance of multipotency in the Müllerian duct mesenchyme

“…However, we were unable to find any evidence of enhanced CTNNB1 expression. Consistent with this, the phenotypic changes observed in the reproductive tracts of Lats1 flox/flox ; Lats2 flox/flox ; Amhr2 cre/+ mice appeared completely unrelated to those in any previously reported mouse models in which WNT signaling was altered in the Müllerian duct (Dunlap et al, 2011;Farah et al, 2017;Franco et al, 2011;Mericskay et al, 2004;Prunskaite-Hyyrylainen et al, 2016;St-Jean et al, 2019;Vainio et al, 1999). Inactivation of Hippo in Lats1 flox/flox ; Lats2 flox/flox ; Amhr2 cre/+ mice did, however, clearly result in the activation of the canonical Hippo effectors YAP and TAZ, as shown by their increased expression, along with that of their transcriptional target genes.…”

“…Moreover, deletion of the Wnt7a gene results in a partially posteriorized female reproductive tract, with uterus-like oviducts and a uterus with histological characteristics of the vagina (Dunlap et al, 2011). Wnt4, Wnt5a and Wnt7a have also all been implicated in uterine gland formation (Dunlap et al, 2011;Farah et al, 2017;Franco et al, 2011;Mericskay et al, 2004;St-Jean et al, 2019). Although the signaling processes whereby WNT ligands direct the development of the female reproductive tract are poorly understood, the canonical WNT signaling effector β-catenin (CTNNB1) is believed to play an important role, largely based on phenotypic abnormalities observed in Ctnnb1 conditional knockout models that mimic to some extent those observed in knockout models of specific WNT genes (Deutscher and Hung-Chang Yao, 2007;Hernandez Gifford et al, 2009).…”

Transcriptional landscape of the embryonic chicken Müllerian duct

“…Terms related to positive and negative Wnt signaling also featured prominently in the GO analysis reported here. Wnt signaling is a well-established conserved pathway required for proper Müllerian duct formation in chicken, mouse and human [ 22 , 35 , 40 , 65 , 66 ]. Wnt9b derived from the Wolffian duct is required for inductive signaling to the incipient Müllerian duct [ 34 ].…”

Protein–protein interaction network analysis applied to DNA copy number profiling suggests new perspectives on the aetiology of Mayer–Rokitansky–Küster–Hauser syndrome

“…Indeed, HNF1B haploinsufficiency is related to uterine and renal malformations in MRKH patients 3 . Notably, in our PPI network LHX1 is a central node of a cluster, interacting with WNT4 and WNT5A, which together with PAX2 and WNT9B are main regulators of Müllerian ducts formation 48,49 . In view of these considerations, our findings confirm LHX1 and HFN1B as strong candidate genes for MRKH syndrome and push towards additional functional studies to better understand their biological role in this syndrome.…”