Integrins and their potential roles in mammalian pregnancy

Altered structural and transporter-related gene expression patterns in the placenta play a role in fetal demise during Porcine reproductive and respiratory syndrome virus infection

BACKGROUND

Porcine reproductive and respiratory syndrome virus (PRRSV) can be transmitted across the maternal-fetal-interface from an infected gilt to her fetuses. Although fetal infection status and disease outcomes vary, the mechanisms are not completely understood. The objective was to assess targeted placental structural and transporter-related gene expression patterns. At day 85 of gestation pregnant pigs were challenged with PRRSV, and at 12 days post maternal infection sows and fetuses were sacrificed, and the placental tissue was collected. Grouping of fetuses was by preservation status and PRRS viral load (VL): control (CTRL, n = 14), viable and low VL fetus (VIA_LVF, n = 15), viable and high VL fetus (VIA_HVF, n = 21), meconium mild and low VL fetus (MECm_LVF, n = 14), meconium mild and high VL fetus (MECm_HVF, n = 14), and meconium severe and high VL fetus (MECs_HVF, n = 13). NanoString was used to evaluate the expression of 86 genes: actin cytoskeleton signaling, arachidonic acid pathway, integrin signaling, intercellular junctions, transporters, and VEGF signaling. Statistical analyses were performed using Limma with P ≤ 0.05 considered significant.

RESULTS

We identified 1, 7, 0, 29, and 39 differentially expressed genes in VIA_LVF, VIA_HVF, MECm_LVF, MECm_HVF, and MECs_HVF, respectively, contrasted to CTRL. Placental transporter genes were significantly impacted (i.e., downregulation of SLC1A3, SLC1A5, SLC2A1, SLC2A3, SLC2A5, SLC2A10, SLC2A12, SLC7A4, SLC16A5, SLC16A10, and SLC27A6; and upregulation of SLC2A2, SLC16A3, and SLC27A4), compared to CTRL. Actin cytoskeleton signaling (ARHGEF6 and ARHGEF7), arachidonic acid (PTGES3 and PTGIS), integrin signaling (FN1 and ITGB6), intercellular junctions (CDH3 and CDH11), and VEGF signaling (MAPK3 and HPSE) gene groupings were significantly impacted, compared to CTRL.

CONCLUSION

Data reported here indicate that fetal PRRSV infection levels rather than fetal demise is necessary for transcriptional dysregulation of the fetal placenta, with a tendency towards more downregulation in the target gene sets among susceptible fetuses. These results generally support that in susceptible fetuses there is altered solute transportation, placental structural integrity, and reduced angiogenesis. The data described here is associated with fetal PRRS resistance/resilience and susceptibility.

CTNNB1 and CDH1 Regulate Trophoblast Cell Adhesion and Junction Formation in Yak Placental Tissue at Different Gestational Stages

Yaks (Bos grunniens), which are distributed across the Tibetan Plateau and other high-altitude regions, are vital livestock that provide essential resources for local herders and have significant economic and ecological value [...].

Repeated implantation failures and infertility in patients are strongly associated with elevated integrin B3 due to endometrial copy number variation

This study reveals the association between gene copy number variants (CNVs) and integrin expression in endometrial tissue, especially focusing on patients with repeated implantation failure and unexplained infertility. The CNV expression, integrin αVβ3 (by real-time quantitative polymerase chain reaction and protein immunoblotting), and related clinical indicators were investigated by analyzing endometrial samples from 48 patients with repeated implantation failures and 10 patients with infertility and with no history of implantation issues. The results revealed the presence of CNVs in approximately 31.04% of patients with infertility, mainly affecting chromosomes 2, 5, 6, 7, 10, 11, 15, 19, and X. Age was associated with CNV occurrence. Integrin β3 expression was significantly higher in the CNV group than in the non-CNV group among patients with repeated implant failure. Clinical indicators related to coagulation were significantly different between the CNV and non-CNV groups. The study indicated a potential association between CNVs, increased integrin β3 expression, and recurrent implant failure. The study provides new information for understanding the complex interactions between genetic variants, integrin function, and coagulation factors by integrating advanced molecular diagnostic techniques, thereby emphasizing the need for a personalized approach in reproductive medicine. These results may redefine the diagnostic paradigm for recurrent implantation failure, laying the foundation for future translational applications.

Tire rubber-derived contaminants 6PPD and 6PPD-quinone reduce attachment and outgrowth of trophoblast spheroids onto endometrial epithelial cells

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), a synthetic additive widely used in the rubber industry, and its oxidized product 6PPD-quinone (6PPDQ), have garnered widespread attention as an emerging hazardous chemicals owing to their potential detrimental effects on aquatic ecosystem and human health. The effects of 6PPD and 6PPDq on the female reproductive tract, especially embryo implantation, remain unknown and were investigated in this study. We used the spheroid attachment and outgrowth models of BeWo trophoblastic spheroids and Ishikawa cells as surrogates for the human blastocyst and endometrial epithelium, respectively. Treatment with the chemicals for up to 48 h decreased the viability of the cells in a dose- and cell line-dependent manner (20-100 μM 6PPD and 10-100 μM 6PPDQ for both the cell lines). At a noncytotoxic concentration, exposure of Ishikawa cells to 1 and 10 μM 6PPD reduced the attachment of BeWo spheroids and further inhibited their invasion and outgrowth on the endometrial epithelial monolayer. A similar result was observed in 1 μM 6PPDQ-exposed groups. Gene expression profiling of 6PPD- and 6PPDQ-exposed endometrial epithelial cells revealed that both 6PPD and 6PPDQ differentially regulated a panel of transcript markers toward overall downregulation of receptivity and invasion. The study provides the first proof of the adverse effects of 6PPD and 6PPDQ on human endometrial receptivity and trophoblast invasion during the window of implantation, warranting the need for further in vivo and clinical studies.

Identification of an osteopontin structural element for the restoration of a normal endometrial epidermal growth factor (EGF) profile determined by the EGF concentration on day 3 of estrous cycle and pregnancy outcome in repeat breeder dairy cows

The loss of a cyclic change with two peaks of increased endometrial epidermal growth factor (EGF) concentration on days 2-4 and 13-14 during the estrous cycle has been linked to low fertility in repeat breeder (RB) cows. We have shown that an intravaginal infusion of osteopontin (OPN) restored the EGF profile in RB cows. The present study aimed to determine a structural element of OPN to restore the normal EGF profile and fertility. Holstein RB cows were diagnosed the EGF profile by a single examination of the endometrial EGF concentration on day 3 of the estrous cycle. Those with an altered EGF profile were intravaginally infused with OPN and its fragments on the day of insemination (day 0); the concentration of endometrial EGF was measured on day 3, and pregnancy was diagnosed on days 30-35. In Study 1, recombinant OPN (rOPN) (16 nmol), thrombin-cleaved N- and C-terminal fragments of rOPN (N-rOPN and C-rOPN, respectively), and a combination of these fragments (Th-rOPN) were infused (n = 13-20). The restoration rate of the normal EGF profile of the N-rOPN group (25.0 %) was a level in between the C-rOPN group (7.7 %) and both the rOPN (55.6 %) and Th-rOPN (64.3 %) groups. In Study 2, PBS (n = 47), rOPN (9.5 nmol, n = 83), and peptides of integrin binding motifs, GRGDSVAYGLK (peptide 1; 32, 320, and 1600 nmol), GRGDS (peptide 2; 320 and 1600 nmol), and SVAYGLK (peptide 3; 320 and 1600 nmol), were infused (n = 20-25). Restoration rates of the normal EGF profile of peptide 1 (320 and 1600 nmol) and peptide 3 (1600 nmol) groups (44.0-56.3 %) were comparable with those of the rOPN group (63.9 %) and higher than those of the PBS group (15.6 %). Restoration rates of the other groups were similar to those of the PBS group. Additional cows received infusions to determine the effect on fertility. Conception rates of the peptide 1 (320 and 1600 nmol; n = 50 each), peptide 3 (1600 nmol; n = 55), and rOPN (n = 111) groups (41.8-50.0 %) were comparable and higher than that of the PBS group (21.6 %, n = 75). In Study 3, PBS (n = 24), peptide 1 (320 nmol; n = 78), and GRGESVAYGLK peptide (peptide 4; 320 and 1600 nmol; n = 50 and 26, respectively) were infused. Restoration rates of the normal EGF profile of peptide 4 and PBS groups (16.0-19.2 %) were comparable and lower than those of the peptide 1 group (44.9 %). Thus, the SVAYGLK motif may be an OPN structural element to restore the normal EGF profile and fertility in RB cows, and the RGD motif may enhance its effect.

ITGB3 is reduced in pregnancies with preeclampsia and its influence on biological behavior of trophoblast cells

BACKGROUND

Preeclampsia (PE) is a serious pregnancy complication associated with impaired trophoblast function. Integrin β3 (ITGB3) is a cell adhesion molecule that plays a role in cell movement. The objective of this study was to identify the biological function and expression level of ITGB3 in PE.

METHODS

Cell proliferation, migration, invasion, adhesion, and apoptosis were estimated by CCK8 assay, transwell, scratch assays, and flow cytometry, respectively. The expression levels of ITGB3 were determined by qRT-PCR, western blot, and immunohistochemistry (IHC). Co-immunoprecipitation and Alphafold-Multimer protein complex structure prediction software were employed to identify the molecules that interact with ITGB3.

RESULTS

Cell functional experiments conducted on HTR8/SVneo cells demonstrated that ITGB3 significantly enhanced proliferation, migration, invasion, and adhesion, while simultaneously inhibiting apoptosis. Relative ITGB3 expression levels were observed to be lower in PE placental tissue than in normal tissue and similarly reduced in hypoxic HTR8/SVneo cells. RNA-sequencing data from PE placental samples in the GEO database were analyzed to identify differentially expressed genes associated with the disease. We identified a total of 1460 mRNAs that were significantly differentially expressed in PE patients. Specifically, 798 mRNAs were significantly upregulated, and 662 mRNAs were significantly downregulated. Notably, the ITGB3 exhibited a pronounced down-regulation among the differential expression mRNA.

CONCLUSIONS

This study suggested that ITGB3 plays an important role in promoting the proliferative, migratory, invasive, and adhesive capabilities of trophoblast cells. These findings may facilitate a more in-depth understanding of the molecular mechanisms that promote PE progression.

Perinatal and obstetric-neonatal outcomes following frozen embryo transfer cycles with a thinner endometrium: a retrospective study

OBJECTIVE

The purpose of this study was to evaluate the relationship of thin endometrial thickness (EMT) on the maternal and child health outcome of frozen-thawed embryo transfer (FET) cycles with singletons.

METHODS

The retrospective cohort study included 1,771 live singleton deliveries, with 273 in the thin endometrium group (EMT ≤ 7.5 mm) and 1,498 in the control group (EMT > 7.5 mm). Pregnancy, perinatal complications and neonatal outcomes were compared between the two groups.

RESULTS

Women in the thinner endometrium group had higher rates of preeclampsia (7.69% vs. 7.00%), placenta previa (4.39% vs. 2.43%), postpartum haemorrhage (15.38% vs. 11.42%) than the control groups, although they were not significantly different. Significant difference was observed in the rates of placental abruption (1.09% vs. 0.07%, P = 0.001), abnormal placental cord insertion (3.66% vs. 1.74%, P = 0.011), placental adherence (15.38% vs. 7.14%, P < 0.001) between the two groups. No significant difference could be found regarding preterm labour, macrosomia, Apgar ≤ 7, large for gestational age (LGA) and appropriate for gestational age (AGA), and singletons from the thinner endometrium group had a significantly lower birthweight than those from the controls. Then after adjusting for confounders, thinner endometrium was still statistically significantly associated with placental adherence, postpartum haemorrhage and low birthweight (LBW).

CONCLUSION

These findings highlight the important role of endometrial thickness in influencing perinatal and obstetric-neonatal outcomes in FET cycles. The study contributes to the growing body of evidence supporting the clinical relevance of endometrial thickness in FET cycles and underscores the need for close monitoring and management of pregnancies in women with a thin endometrium. Future research should focus on elucidating the underlying mechanisms and identifying effective interventions to improve endometrial thickness and pregnancy outcomes in this patient population.

MicroRNAs, endometrial receptivity and molecular pathways

MicroRNAs (miRNAs) are a type of specific molecules that control the activities of the uterus, such as the process of cellular maturing and evolution. A lot of substances like growth factors, cytokines, and transcription factors play a role in embryo-endometrial interaction. MiRNAs could regulate various these factors by attaching to the 3' UTR of their mRNAs. Moreover, current research show that miRNAs participate in formation of blood vessels in endometrium (miR-206, miR-17-5p, miR-16-5p…), decidualization (miR-154, miR-181, miR-9…), epithelial-mesenchymal transition (miR-30a-3p), immune response (miR-888, miR-376a, miR-300…) embryo attachment (miR-145, miR-27a,451…) and pinopod formation (mir-223-3p, mir-449a, mir-200c). In this study, the focus is on the role of miRNAs in managing the uterus' receptivity to an embryo and its ability to facilitate attachment. More specifically, we are exploring the mechanisms by which miRNAs regulate the presence of specific molecules involved in this crucial physiological process.

Cyclosporine A improves the binding of mouse embryos to fibronectin

AIM

The binding of integrin αvβ3 with endometrial fibronectin (FN) promotes the migration of preimplantation embryos in mice. We have previously shown that cyclosporine A (CsA) improves the adhesion and invasion of mouse preimplantation embryos. In this study, we evaluated the roles of calcium ions and downstream signaling factors in the binding of integrin αvβ3 to FN.

METHODS

Female Institute of Cancer Research (ICR) mice were superovulated and mated, and two-cell embryos were harvested from the oviducts and cultured to the blastocyst stage The adhesion and stretching growth of hatched embryos in laminin-coated dishes were evaluated, and integrinβ3 expression was determined using qPCR. Blastocytes were cultured with 0 or 1  μM cyclosporine A (CsA) and the attachment of embryonic integrin αvβ3 to FN120 was observed using a fluorescent bead. To further determine the mechanism, the cells were also incubated with calcium ions and protein kinase C and calmodulin antagonists. The binding of integrin αvβ3 to FN120 was examined via confocal laser scanning microscopy.

RESULTS

The adhesion and stretching growth of peri-implantation embryos were greater and integrinβ3 expression was higher in the 1 μM CsA group than in the 0 μM CsA group (p < 0.05). When incubated with calcium ions and protein kinase C and calmodulin antagonists, the ability of peri-implantation embryos to bind to FN decreased; CsA treatment promoted this binding.

CONCLUSION

This study revealed that CsA up - regulates integrinβ3 expression in peri - implantation embryos and promotes binding to FN via calcium ions, and protein kinase C, and calmodulin. These findings provide evidence supporting the beneficial effect of CsA on the peri - implantation embryo adhesion.

Endometrial responsiveness to interferon-tau and its association with subsequent reproductive performance in dairy heifers

Our objectives were to evaluate the endometrial responsiveness of dairy heifers to an intrauterine infusion of recombinant bovine interferon-tau (rbIFN-τ) and to associate endometrial responses to rbIFN-τ with subsequent reproductive performance. In experiments 1 and 2, cyclic heifers were enrolled in a program for synchronization of the estrous cycle, and blood sampling and ultrasonography examinations were performed on d 0, 4, 7, 11, and 14 of the estrous cycle. In experiment 1, heifers were randomly assigned to receive an intrauterine infusion containing 2 µg of rbIFN-τ (rbIFN-τ = 19) or saline control (CTRL = 19) into the uterine horn ipsilateral to the corpus luteum (CL) on d 14 of the estrous cycle. Then, 6 hours after the infusion, the infused uterine horn was flushed for sampling of the uterine luminal fluid (ULF) for composition analysis, and the endometrium was biopsied for transcriptomics. In experiment 2, 100 heifers received an intrauterine infusion of rbIFN-τ, and the same procedures for uterine sample collection were performed as described in experiment 1. After the intrauterine test, heifers were enrolled in a breeding program and classified as highly fertile (HF; pregnant at first AI) or subfertile (SF; not pregnant at first AI). Statistical analyses were performed using regression models, which included the effects of treatment (experiment 1: CTRL vs. rbIFN-τ) or fertility group (experiment 2: HF vs. SF) and block of samples. Intrauterine infusion of rbIFN-τ increased the expression of classical interferon-stimulated genes in the endometrium (e.g., ISG15, MX1, OAS2, IRF9, and USP18), and an antiviral response was predicted to be the main downstream effect of the transcriptome changes. In addition, rbIFN-τ increased the abundance of cholesterol, glycerol, and the overall concentration of oxylipins in the ULF. Analysis of endometrial transcriptome between HF and SF heifers revealed important differences in the expression of genes associated with cell signaling, metabolism, attachment, and migration, with a large representation of genes encoding extracellular matrix proteins. In general, differentially expressed genes were expected to be downregulated by IFN-τ but seemed to fail to be downregulated in SF heifers, resulting in higher expression in SF compared with HF heifers. Subfertile heifers had lower concentrations of glycerol and an altered profile of oxylipins in the ULF, with a lower abundance of oxylipins derived from arachidonic acid and dihomo-γ-linolenic acid, and a greater abundance of oxylipins derived from linoleic acid. Measurements of ovarian function did not differ between groups and, therefore, did not influence the observed results in uterine biology. Overall, the endometrial responsiveness to IFN-τ is variable among individuals and associated with subsequent fertility of heifers, indicating that communication between conceptus and endometrium is critical for the uterine receptivity and survival of pregnancy.

Osteopontin: A Key Multifaceted Regulator in Tumor Progression and Immunomodulation

The tumor microenvironment (TME) is composed of various cellular components such as tumor cells, stromal cells including fibroblasts, adipocytes, mast cells, lymphatic vascular cells and infiltrating immune cells, macrophages, dendritic cells and lymphocytes. The intricate interplay between these cells influences tumor growth, metastasis and therapy failure. Significant advancements in breast cancer therapy have resulted in a substantial decrease in mortality. However, existing cancer treatments frequently result in toxicity and nonspecific side effects. Therefore, improving targeted drug delivery and increasing the efficacy of drugs is crucial for enhancing treatment outcome and reducing the burden of toxicity. In this review, we have provided an overview of how tumor and stroma-derived osteopontin (OPN) plays a key role in regulating the oncogenic potential of various cancers including breast. Next, we dissected the signaling network by which OPN regulates tumor progression through interaction with selective integrins and CD44 receptors. This review addresses the latest advancements in the roles of splice variants of OPN in cancer progression and OPN-mediated tumor-stromal interaction, EMT, CSC enhancement, immunomodulation, metastasis, chemoresistance and metabolic reprogramming, and further suggests that OPN might be a potential therapeutic target and prognostic biomarker for the evolving landscape of cancer management.

Early Embryonic Development in Agriculturally Important Species

The fertilization of oocytes ovulated by pigs, sheep, cows, and horses is not considered a limiting factor in successful establishment of pregnancy. Pig, sheep, and cow embryos undergo cleavage to the blastocyst stage, hatch from the zona pellucida, and undergo central-type implantation. Hatched blastocysts of pigs, sheep, and cows transition from tubular to long filamentous forms to establish surface area for exchange of nutrients and gases with the uterus. The equine blastocyst, surrounded by external membranes, does not elongate but migrates throughout the uterine lumen before attaching to the uterine luminal epithelium (LE) to begin implantation. Pregnancy recognition signaling in pigs requires the trophectoderm to express interleukin 1 beta, estrogens, prostaglandin E2, and interferon gamma. Sheep and cow conceptus trophectoderm expresses interferon tau that induces interferon regulatory factor 2 that inhibits transcription of estrogen and oxytocin receptors by uterine epithelia. This prevents oxytocin-induced luteolytic pulses of prostaglandin F2-alpha from regressing the corpora lutea, as well as ensuring the secretion of progesterone required for maintenance of pregnancy. The pregnancy recognition signal produced by equine blastocysts is not known. Implantation in these species requires interactions between extracellular matrix (ECM) proteins and integrins as the conceptus undergoes apposition and firm attachment to the uterine LE. This review provides details with respect to early embryonic development and the transition from spherical to filamentous conceptuses in pigs, sheep, and cows, as well as pre-implantation development of equine blastocysts and implantation of the conceptuses.

Genome-wide association study identifies genomic regions associated with key reproductive traits in Korean Hanwoo cows

BACKGROUND

Conducting genome-wide association studies (GWAS) for reproductive traits in Hanwoo cattle, including age at first calving (AFC), calving interval (CI), gestation length (GL), and number of artificial inseminations per conception (NAIPC), is of paramount significance. These analyses provided a thorough exploration of the genetic basis of these traits, facilitating the identification of key markers for targeted trait improvement. Breeders can optimize their selection strategies, leading to more efficient and sustainable breeding programs, by incorporating genetic insights. This impact extends beyond individual traits and contributes to the overall productivity and profitability of the Hanwoo beef cattle industry. Ultimately, GWAS is essential in ensuring the long-term genetic resilience and adaptability of Hanwoo cattle populations. The primary goal of this study was to identify significant single nucleotide polymorphisms (SNPs) or quantitative trait loci (QTLs) associated with the studied reproductive traits and subsequently map the underlying genes that hold promise for trait improvement.

RESULTS

A genome-wide association study of reproductive traits identified 68 significant single nucleotide polymorphisms (SNPs) distributed across 29 Bos taurus autosomes (BTA). Among them, BTA14 exhibited the highest number of identified SNPs (25), whereas BTA6, BTA7, BTA8, BTA10, BTA13, BTA17, and BTA20 exhibited 8, 5, 5, 3, 8, 2, and 12 significant SNPs, respectively. Annotation of candidate genes within a 500 kb region surrounding the significant SNPs led to the identification of ten candidate genes relevant to age at first calving. These genes were: FANCG, UNC13B, TESK1, TLN1, and CREB3 on BTA8; FAM110B, UBXN2B, SDCBP, and TOX on BTA14; and MAP3K1 on BTA20. Additionally, APBA3, TCF12, and ZFR2, located on BTA7 and BTA10, were associated with the calving interval; PAX1, SGCD, and HAND1, located on BTA7 and BTA13, were linked to gestation length; and RBM47, UBE2K, and GPX8, located on BTA6 and BTA20, were linked to the number of artificial inseminations per conception in Hanwoo cows.

CONCLUSIONS

The findings of this study enhance our knowledge of the genetic factors that influence reproductive traits in Hanwoo cattle populations and provide a foundation for future breeding strategies focused on improving desirable traits in beef cattle. This research offers new evidence and insights into the genetic variants and genome regions associated with reproductive traits and contributes valuable information to guide future efforts in cattle breeding.

Norflurazon causes cell death and inhibits implantation-related genes in porcine trophectoderm and uterine luminal epithelial cells

Norflurazon, an inhibitor of carotenoid synthesis, is a pre-emergent herbicide that prevents growth of weeds. The norflurazon is known to hamper embryo development in non-mammals. However, specific toxic effects of norflurazon on mammalian maternal and fetal cells have not been elucidated. Thus, the hypothesis of this study is that norflurazon may influence the toxic effects between maternal and fetal cells during early pregnancy in pigs. We aimed to examine the toxic effects of norflurazon in porcine trophectoderm (Tr) and uterine luminal epithelium (LE) cells. Norflurazon, administered at 0, 20, 50 or 100 μM for 48 h was used to determine its effects on cell proliferation and cell-cycle arrest. For both uterine LE and Tr cell lines, norflurazone caused mitochondrial dysfunction by inhibiting mitochondrial respiration and ATP production, and down-regulated expression of mRNAs of mitochondrial complex genes. Norflurazon increased cell death by increasing intracellular calcium and regulating PI3K and MAPK cell signaling pathways, as well as endoplasmic reticulum (ER) stress, ER-mitochondrial contact, and autophagy-related target proteins. Norflurazone also inhibited expression of genes required for implantation of blastocysts, including SMAD2, SMAD4, and SPP1. These findings indicate that norflurazon may induce implantation failure in pigs and other mammals through adverse effects on both Tr and uterine LE cells.

In vitro effects of heparin-binding epidermal growth factor on adhesion stage of implantation

A member of the epidermal growth factor (EGF) family, the heparin-binding EGF (HB-EGF) is expressed in the uteri of both humans and mice during the implantation process. To study the effects of HB-EGF on adhesion stage, we developed an in vitro implantation model employing Ishikawa cell line and JAR cell line, which may attach to Ishikawa cells. For 1, 6, 12, and 24 hours, co-cultures of JAR spheroids grown on Ishikawa monolayers were treated with 1, 10, and 100 ng∕mL doses of HB-EGF. Using immunocytochemistry and Western blot analysis, the effects of HB-EGF on the protein expressions of E-cadherin, Erb-B2 receptor tyrosine kinase 4 (ErbB4), and integrin ανβ3 in Ishikawa and JAR cells were examined semi-quantitatively and quantitatively. Ultrastructural changes of in vitro implantation model were investigated by transmission electron microscopy. We revealed that HB-EGF influenced trophoblast cell adhesion to endometrial cells by upregulating the expression of the proteins ErbB4 and trophoblastic integrin ανβ3. Decrease in trophoblastic E-cadherin expression and increase in endometrial E-cadherin expression were demonstrated accompanying morphological variations in cells required for the invasion. We discovered ultrastructurally that Ishikawa cells acquired uterodome-like appearance, including the organelles, when 10 and 100 ng∕mL dosages of HB-EGF were administered for 12 and 24 hours. However, following additional hours of adhesion and invasion, their intercellular spaces enlarged. The trafficking of vesicular transport was enhanced by JAR spheroids. We therefore discovered that in this implantation paradigm, HB-EGF may enhance the receptivity of Ishikawa cells and the adherence of JAR cells.