miR-149-PARP-2 Signaling Regulates E-cadherin and N-cadherin Expression in the Murine Model of Endometrium Receptivity

Cadherins play an essential role in the attachment of the blastocyst to the endometrium, a process known as endometrial receptivity. Loss of E-cadherin expression is essential during the process, while the expression level of the other cadherin, N-cadherin, has been reported to be altered in cases of infertility. Both E-cadherin and N-cadherin can be regulated by members of the PARP family. Specifically, PARP-2, which is under the epigenetic control of miR-149, has been observed to promote E-cadherin expression in other human cells. We investigated the roles of E-cadherin and N-cadherin in endometrial receptivity using mouse models for normal endometrial receptivity, pseudopregnancy, and LPS-induced endometrial receptivity failure. E-cadherin and phosphorylated E-cadherin were predominantly expressed during pre-receptive stages as well as in the implantation site of the receptive stage, which were observed reduced during the later stages of implantation in both implantation and non-implantation regions, while N-cadherin was detected only at pre-receptive stages. E-cadherin and N-cadherin were also seen in the uterus during pseudopregnancy, showing a downregulation trend during receptive and post-receptive stages. LPS-induced failed endometrial receptivity showed upregulation of E-cadherin and downregulation of N-cadherin. The E-cadherin expression promoter, GSK-3, was lost and its suppressor, SLUG was upregulated during normal course of endometrial receptivity in mouse model, while GSK-3 was increased during LPS-induced failed embryo implantation. In an in vitro model of embryo implantation, E-cadherin expression is promoted by PARP-2 and regulated by miR-149 epigenetically in human endometrium epithelial cells. In conclusion, E-cadherin is predominantly expressed during pre-receptive stage and promoted by PARP-2, which is regulated by miR-149 in the endometrial epithelial cells.

miRNA-149 targets PARP-2 in endometrial epithelial and stromal cells to regulate the trophoblast attachment process

Embryo implantation is a highly complex process involving many regulatory factors, including several micro RNAs (miRNAs/miRs). One miRNA present in the stromal cells of normal endometrium is miR-149, which targets poly (ADP-ribose) polymerase 2 (PARP-2), a gene involved in endometrial receptivity for trophoblast implantation. However, the precise role of miR-149 in the endometrial receptivity during blastocyst implantation is still unknown. We studied miR-149-dependent PARP-2 regulation during trophoblast attachment to endometrial epithelial cells. Using FISH, we found that miR-149 is expressed in mouse endometrial epithelial and stromal cells at implantation and inter-implantation sites. Endometrial receptivity for embryo implantation and attachment is inhibited by the upregulation of miR-149 in the endometrium. Our RT-PCR analysis revealed downregulation of miR-149 in the implantation region of the uterus during the receptive stage (Day 5, 0500 h, p.c.) in the mouse. Under in-vitro conditions, miR-149 overexpression in human endometrial epithelial cells (hEECs) abrogated the human trophoblastic cells spheroid and mouse blastocyst attachment. Subsequently, miR-149 also regulates transformed human endometrial stromal cell (T-hESCs) decidualization by downregulating PARP-2 and upregulating caspase-8 proteins. Overexpression of miR-149 in hEECs and downregulated PARP-2 protein expression, reconfirming that PARP-2 is a downstream target of miR-149 in endometrial cells as well. miR-149 is also able to alter the expression of caspase-8, another PARP-2 regulator. In conclusion, our data indicate that miR-149 is one of the regulators of endometrial receptivity and decidualization for trophoblast implantation, and it exerts the effects by acting on the downstream targets PARP-2 and caspase-8.

Poly(ADP-ribose) polymerase-2 is essential for endometrial receptivity and blastocyst implantation, and regulated by caspase-8

Embryo implantation is a very complex process and several factors play important roles. Using a mouse model, we investigated the functions of PARP-2 and caspase-8 during endometrial receptivity for blastocyst implantation. We found that PARP-2 was upregulated at the receptive stage's implantation region and predominantly expressed in the endometrial stromal region, but downregulated during pregnancy failure and pseudopregnancy. To reinforce the necessity of PARP-2 for embryo implantation, we pharmacologically inhibited PARP-2 'before' & 'after' embryo arrival and observed a reduction in blastocyst implantation. Conversely, elevated caspase-8 expression and activity during pseudopregnancy, delayed implantation, and embryo implantation failure conditions and decreased levels in the decidualization exhibited an inverse pattern with PARP-2, suggesting caspase-8 as a negative regulator for embryo implantation. In vitro caspase-8 downregulates the PARP-2 activity in the mouse endometrial epithelial and stromal cells. These data suggest that PARP-2 and its negative regulation by caspase-8 constitute a crucial step in embryo implantation.

CD44 targeting hyaluronic acid coated lapatinib nanocrystals foster the efficacy against triple-negative breast cancer

Lapatinib (LPT) is an orally administered drug for the treatment of metastatic breast cancer. For expanding its therapeutic horizon, we have prepared its nanocrystals (LPT-NCs) that were subsequently coated with hyaluronic acid (HA) to produce LPT-HA-NCs. The detailed in-vitro and in-vivo investigation of LPT-HA-NCs showed the superior anticancer activity due to active targeting to CD44 receptors than the counterparts LPT-NCs and free LPT. In the triple negative 4T1 cells induced breast tumor bearing female Balb/C mice; LPT-HA-NCs treatment caused significant retardation of tumor growth and overall increase in animal survival probability because of their higher tumor localization, increased residence time. Our findings clearly suggest that HA coated LPT-NCs formulation enhances the activity of LPT against triple negative breast cancer. It exhibited magnificent therapeutic outcome at low dose thus presenting a strategy to reduce dose administrations and minimize dose related toxicity.

Endoglin (CD105) coordinates the process of endometrial receptivity for embryo implantation

Endoglin is a TGF-β receptor that is expressed in uterine endothelial and stromal cells in addition to trophoblast expression. However, the functional importance of endoglin in the embryo implantation process is not clear. We observed endoglin expression in the endometrium throughout the stages of its receptivity; however, its expression was enhanced during the receptive stage. Endoglin expression was predominant in epithelial cells of the lumen and glands, but showed a milder expression in stromal cells. Endoglin expression was initially observed in the primary decidual zone and later extended to the secondary decidua zone. Knockdown of endoglin via siRNA reduced the implantation sites along with the blastocyst numbers. Mouse blastocyst with endoglin-silenced endometrial epithelial cells (human and mouse origin) showed poor trophoblast outgrowth, which suggests an essential role for endoglin during endometrial receptivity. In conclusion, our findings reveal the association of endoglin with endometrial receptivity, which is important for embryo attachment.