Gja1 acts downstream of Acvr1 to regulate uterine decidualization via Hand2 in mice

et al. 2018

J Exp Zool Pt B

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Although Egr2 is involved in regulating the folliculogenesis and ovulation, there is almost no data describing its physiological function in embryo implantation and decidualization. Here, we showed that Egr2 mRNA was distinctly accumulated in subluminal stromal cells around implanting blastocyst on day 5 of pregnancy as well as in estrogen-activated implantation uterus. Estrogen induced the expression of Egr2 in uterine epithelia. Elevated expression of Egr2 mRNA was also observed in the decidual cells. Silencing of Egr2 by specific siRNA weakened the proliferation of uterine stromal cells and reduced the expression of Ccnd1, Ccnd3, Cdk4, and Cdk6. Furthermore, Egr2 advanced the expression of Prl8a2, Prl3c1, and Pgr, the well-established differentiation markers for decidualization. Administration of exogenous recombinant heparin-binding EGF-like growth factor (rHB-EGF) to uterine stromal cells resulted in an increase in the level of Egr2 mRNA. Moreover, siRNA-mediated attenuation of Egr2 impeded the stimulation of HB-EGF on stromal cell differentiation. Knockdown of Egr2 led to a reduction in the expression of Cox-2, mPGES-1, Vegf, Trp53, and Mmp2. Further analysis found that Egr2 may serve as an intermediate to mediate the regulation of HB-EGF on Cox-2, mPGES-1, Vegf, Trp53, Mmp2, and Ccnd3. Collectively, Egr2 may play an important role during embryo implantation and decidualization.

Section: Discussionmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

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Egr2 mediates the differentiation of mouse uterine stromal cells responsiveness to HB‐EGF during decidualization

Yue

et al. 2018

J Exp Zool Pt B

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“…Meanwhile, knockdown of Hmgn5, which was a novel discovered member of Hmgn family and crucial for decidualization [15], enhanced the expression of Hmgn2 in uterine stromal cells (our unpublished data), suggesting that Hmgn2 may functionally compensate the role of Hmgn5 in stromal differentiation. Further analysis revealed that Hmgn2 could stimulate the expression of Hand2 whose knockdown damaged the stromal differentiation in both mice and human [30, 34], implying that Hand2 may be a downstream regulator of Hmgn2 during decidualization. Previous studies have established that Hmgn2 was involved in transcriptional regulation of numerous genes by affecting histone modifications and activity of ATP-dependent chromatin remodeling complexes, or binding to chromatin regulatory sites such as Dnase I-hypersensitive sites, enhancers and promoters [11, 14, 29, 35], but the regulatory mechanism of Hmgn2 on the expression of Hand2 in uterine stromal cells remains to be determined.…”

Section: Discussionmentioning

confidence: 99%

Evidence For Hmgn2 Involvement in Mouse Embryo Implantation and Decidualization

Yue

et al. 2017

Cell Physiol Biochem

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Background/Aims: Hmgn2 is involved in regulating embryonic development, but its physiological function during embryo implantation and decidualization remains unknown. Methods: In situ hybridization, real-time PCR, RNA interference, gene overexpression and MTS assay were used to examine the expression of Hmgn2 in mouse uterus during the pre-implantation period and explore its function and regulatory mechanisms in epithelial adhesion junction and stromal cell proliferation and differentiation. Results: Hmgn2 was primarily accumulated in uterine luminal epithelia on day 4 of pregnancy and subluminal stromal cells around the implanting blastocyst at implantation sites on day 5. Similar results were observed during delayed implantation and activation. Meanwhile, Hmgn2 expression was visualized in the decidua. In uterine epithelial cells, silencing of Hmgn2 by specific siRNA reduced the expression of adhesion molecules Cdh1, Cdh2 and Ctnnb1 and enhanced the expression of Muc1, whereas constitutive activation of Hmgn2 exhibited the opposite effects, suggesting a role for Hmgn2 in attachment reaction during embryo implantation. Estrogen stimulated the expression of Hmgn2 in uterine epithelia, but the stimulation was abrogated by ER antagonist ICI 182,780. Further analysis evidenced that attenuation of Hmgn2 might eliminate the regulation of estrogen on the expression of Cdh1, Cdh2 and Ctnnb1. In uterine stromal cells, progesterone induced the accumulation of Hmgn2 which advanced the expression of Prl8a2 and Prl3c1, two well-known differentiation markers for decidualization, but did not affect the proliferation of stromal cells. Knockdown of Hmgn2 blocked the progesterone-induced differentiation of uterine stromal cells. Moreover, Hmgn2 might serve as an intermediate to mediate the regulation of progesterone on Hand2. Conclusion: Hmgn2 may play an important role during embryo implantation and decidualization.

“…It is generally considered that uterine decidualization is accompanied by elevated intracellular cAMP levels which prominently activates protein kinase A (PKA) signal transduction pathway [18,19]. In uterine stromal cells, cAMP analogue 8-bromoadenosinecAMP (8-Br-cAMP, 500 μM) up-regulated the expression of Hmgb1 at 48 h, whereas PKA inhibitor H89 (10 μM) abrogated the up-regulation of Hmgb1 elicited by 8-Br-cAMP (Fig.…”

Section: Hmgb1 Mediates the Effects Of Camp On The Differentiation Ofmentioning

confidence: 99%

High Mobility Group Box 1 Regulates Uterine Decidualization through Bone Morphogenetic Protein 2 and Plays a Role in Kruppel-Like Factor 5-Induced Stromal Differentiation

Wang

et al. 2018

Cell Physiol Biochem

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Background/Aims: High mobility group box 1 (Hmgb1) is associated with a variety of physiological processes including embryonic development, cell proliferation and differentiation, but little information is available regarding its biological role in decidualization. Methods: In situ hybridization, real-time PCR, RNA interference, gene overexpression and MTS assay were used to analyze the spatiotemporal expression of Hmgb1 in mouse uterus during the pre-implantation period, and explore its function and regulatory mechanisms during uterine decidualization. Results: Hmgb1 mRNA was obviously observed in uterine epithelium on day 2 and 3 of pregnancy, but its expression was scarcely detected on day 4 of pregnancy. With the onset of embryo implantation, abundant Hmgb1 expression was noted in the subluminal stromal cells around the implanting blastocyst at implantation sites. Meanwhile, the accumulation of Hmgb1 mRNA was visualized in the decidual cells. Hmgb1 advanced the proliferation of uterine stromal cells and induced the expression of prolactin family 8, subfamily a, member 2 (Prl8a2), a reliable differentiation marker for decidualization. In uterine stromal cells, cAMP analogue 8-Br-cAMP up-regulated the expression of Hmgb1, but the up-regulation was abrogated by protein kinase A (PKA) inhibitor H89. Silencing of Hmgb1 by specific siRNA impeded the induction of 8-Br-cAMP on Prl8a2. Further analysis evidenced that Hmgb1 was a critical mediator of Kruppel-like factor 5 (Klf5) function in stromal differentiation. Knockdown of bone morphogenetic protein 2 (Bmp2) prevented the up-regulation of Prl8a2 elicited by Hmgb1 overexpression, whereas addition of exogenous recombinant Bmp2 protein (rBmp2) reversed the repression of Hmgb1 siRNA on Prl8a2 expression. Conclusion: Hmgb1 may play an important role during mouse uterine decidualization.