Müllerian inhibiting substance regulates its receptor/SMAD signaling and causes mesenchymal transition of the coelomic epithelial cells early in Müllerian duct regression

Abstract

Examination of Müllerian inhibiting substance (MIS) signaling in the rat in vivo and in vitro revealed novel developmental stageand tissue-specific events that contributed to a window of MIS responsiveness in Müllerian duct regression. The MIS type II receptor (MISRII)-expressing cells are initially present in the coelomic epithelium of both male and female urogenital ridges, and then migrate into the mesenchyme surrounding the male Müllerian duct under the influence of MIS. Expression of the genes encoding MIS type I receptors, Alk2 and Alk3, is also spatiotemporally controlled; Alk2 expression appears earlier and increases predominantly in the coelomic epithelium, whereas Alk3 expression appears later and is restricted to the mesenchyme, suggesting sequential roles in Müllerian duct regression. MIS induces expression of Alk2, Alk3 and Smad8, but downregulates Smad5 in the urogenital ridge. Alk2-specific small interfering RNA (siRNA) blocks both the transition of MISRII expression from the coelomic epithelium to the mesenchyme and Müllerian duct regression in organ culture. Müllerian duct regression can also be inhibited or accelerated by siRNA targeting Smad8 and Smad5, respectively. Thus, the early action of MIS is to initiate an epithelial-tomesenchymal transition of MISRII-expressing cells and to specify the components of the receptor/SMAD signaling pathway by differentially regulating their expression. Development 133, 2359Development 133, -2369Development 133, (2006Development 133, ) doi:10.1242 Pediatric Surgical Research Laboratories, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. KEY WORDS: MIS, MIS type I/II receptor, SMAD, Epithelial-to-mesenchymal transition, RNA interference, Organ culture, Rat*Author for correspondence (e-mail: donahoe.patricia@mgh.harvard.edu) Accepted 30 March 2006DEVELOPMENT 2360 phosphorylated SMADs translocate into the nucleus complexed with SMAD4 and transcriptionally regulate specific sets of targeted genes (for reviews, see Massagué, 2000; Attisano and Wrana, 2002). MIS has been shown to activate SMAD1 (Gouédard et al., 2000;Clarke et al., 2001;Visser et al., 2001) and SMAD5 (Visser et al., 2001) in vitro, implying that R-SMADs 1, 5 and 8 may mediate Müllerian duct regression (Kobayashi and Behringer, 2003).The present study was undertaken to define when and where the MIS type I receptors are employed and to determine which SMADs transduce MIS signals in the urogenital ridge during Müllerian duct regression. We adapted RNA interference (RNAi) (Calegari et al., 2002;Sakai et al., 2003;Soutschek et al., 2004) to test functional activity of the components of the MIS signaling pathway in a urogenital ridge organ culture assay, which recapitulates the morphological events occurring in vivo during Müllerian duct regression . We show that ALK2-mediated MIS signaling induces migration of MISRII-expressing cells from the coelomic epithelium into the Müllerian duct mesenchyme, and thus is responsible for the sexual dimorp...

Normal ovarian surface epithelial label-retaining cells exhibit stem/progenitor cell characteristics

“…2 A-C), which lends support to the dual epithelial/mesenchymal potential ascribed to the ovarian coelomic epithelium (34,35). Interestingly, whereas ovarian cancer cells express the surface marker EpCam (36,37), the CE LRCs were negative (see Fig.…”

Molecular analysis of the β-catenin gene in patients with the Mayer-Rokitansky-Küster-Hauser syndrome

“…CTNNB1 seemed a particularly interesting candidate gene, since β-catenin is a downstream effector of both AMH and WNT signaling pathways, which may function cooperatively in mediating Müllerian duct regression [24]. Whether the effect of AMH involves WNT signaling in the Müllerian mesenchyme is unknown.…”

Mullerian Inhibiting Substance enhances subclinical doses of chemotherapeutic agents to inhibit human and mouse ovarian cancer

“…The present studies were undertaken to determine the agents with which MIS could be used most efficaciously. For example, MIS exerts its effect in the embryonic urogenital ridge by activating MISRII, Alk2 and Alk3, and the Smad 1͞5͞8 differentiation and growth inhibitory pathway (35). In addition, MIS up-regulates pocket proteins p130 and p107 in human ovarian (10) and endometrial cancer cell lines (9).…”

“…Comprehensive studies in our laboratory, and in those of many others, have shown that MIS downstream signal transduction pathways include MISRII (28)(29)(30), the type I receptors Alk2 (31) and Alk3 (32), Smads 1͞5͞8 (33)(34)(35), cyclin-dependent kinase inhibitors (4, 9, 10), and cytokine-inducible pathways (36)(37)(38)(39), suggesting mechanisms of action that are potentially different from those of most cytotoxic drugs.…”