The expression of CD9 in the peri-implantation mouse uterus is upregulated in an ovarian steroid hormone-dependent manner

Investigation of conceptus stimulated gene expression in buffalo peripheral blood mononuclear cells as potential diagnostic markers of early pregnancy

Exploration of novel strategies for early pregnancy diagnosis is pivotal in enhancing the reproductive potential and monetary gains from dairy herds. In buffalo, the trophectoderm cells of the elongating conceptus secrete interferon-tau that stimulates the transcription of various genes in peripheral blood mononuclear cells (PBMC) during the peri-implantation period. We explored the differential expression of classical (ISG15) and novel (LGALS3BP and CD9) early pregnancy markers in PBMC of buffaloes during various stages of pregnancy. Natural heat was detected in buffaloes by assessing the vaginal fluid, and artificial insemination (AI) was done. Whole blood was collected from the jugular vein in EDTA-containing vacutainers for PBMC isolation before AI (0-day) and 20, 25 and 40 d post-AI. On day 40, transrectal ultrasonography examination was performed to confirm pregnancy. The inseminated non-pregnant animals served as control. Total RNA was extracted using the TRIzol method. The temporal abundance of ISG15, LGALS3BP and CD9 genes in PBMC was compared between pregnant and non-pregnant groups (n = 9 per group) using real time-qPCR. Results showed transcripts of ISG15 and LGALS3BP were more abundant at 20 d in the pregnant group compared to the 0 d and 20 d values of the non-pregnant group. However, due to variability in expression, threshold (Ct) cycle of RT-qPCR alone could not distinguish pregnant and non-pregnant animals. In conclusion, ISG15 and LGALS3BP transcripts abundance in PBMCs are potential candidate biomarkers for early prediction of buffalo pregnancy 20-days post-AI, but further work is required to allow the development of a reliable new methodology.

The increased level of Tspan5 in villi suggests more proliferation and invasiveness of trophoblasts in tubal pregnancy

OBJECTIVE

This study was to determinate the expression of Tspan5 in tubal ectopic implantation sites and to explore the correlation of the expressive level of Tspan5 at maternal-fetal interface and the occurrence of tubal ectopic pregnancy.

STUDY DESIGN

This is a retrospective study. Trophoblastic and endometrial tissues were collected from tubal ectopic pregnancy(Total of 40), and intrauterine pregnancy(Total of 41), who had voluntary abortion, non-pregnancy women(Total of 12), who recieved an diagnostic uterine curettage before IVF-ET for male infertility. All samples were collected from women aged 23-40 years, from February 2012 to January 2014. Results 1. In human villi Tspan5 was primarily located in cytoplasm and on the surfaces of cytotroblasts(CTs) and extravillous trophoblast(EVCTs). The intensity of Tspan5 in tubal pregnancy was significantly higher than that in normal intrauterine pregnancy, showing significant differences (Mean of IOD:109.39 ± 61.84 Vs. 89.04 ± 36.44;t = 2.33, P = 0.023). 2. In human deciduas of intrauterine pregnancy or endometrium of tubal pregnancy and non-pregnancy Tspan5 expressed in cytoplasm and membrane of glandular epithelial cells. The expressive level of this protein was increased in tubal pregnancy than that in intrauterine pregnancy and non-pregnancy(Mean of IOD:144.18 ± 106.22 Vs. 93.43 ± 67.10, P = 0.037; 144.18 ± 106.22 Vs. 88.56 ± 33.24, P = 0.018).

CONCLUSION

Our study indicated that the trophoblasts in tubal pregnancy showed more proliferative and invasive characteristics. Dysregulation of Tspan5 in decidual microenvironment may relate to the retention of embryo in fallopian tube.

SUPPORT

This study was Supported by Science and Technology Planning Project of Guangdong Province.

Molecular characterization of CD9 and CD63, two tetraspanin family members expressed in trout B lymphocytes

Tetraspanins are a family of membrane-organizing proteins, characterized by the presence of four highly conserved transmembrane regions that mediate diverse physiological functions. In the current study, we have identified two novel tetraspanin members in rainbow trout (Oncorhynchus mykiss), homologs to mammalian CD9 and CD63. Both genes were expressed in muscle, skin, gills, hindgut, gonad, liver, spleen, head kidney, thymus and peripheral blood leukocytes. Throughout the early life cycle stages, CD9 mRNA levels significantly increased after first feeding, whereas CD63 transcription remained constant during all the developmental stages analyzed. In response to an experimental bath infection with viral hemorrhagic septicemia virus (VHSV), CD9 transcription was down-regulated in the gills, while CD63 mRNA levels were down-regulated in the head kidney. Instead, when the virus was intraperitoneally injected, the transcription of both genes was significantly up-regulated in peritoneal cells at several days post-infection. Additionally, both genes were transcriptionally up-regulated in the muscle of trout injected with a VHSV DNA vaccine. To gain insight on the relation of these tetraspanins with B cell activity we determined their constitutive expression in naive IgM(+) populations from different sources and observed that both molecules were being transcribed by IgM(+) cells in different tissues. Furthermore, CD9 transcription was significantly down-regulated in splenic IgM(+) cells in response to in vitro VHSV exposure. Our results provide insights on the potential role of these tetraspanins on teleost B cell and antiviral immunity.

Involvement of microRNA lethal-7a in the regulation of embryo implantation in mice

MicroRNAs interact with multiple mRNAs resulting in their degradation and/or translational repression. This report used the delayed implantation model to determine the role of miRNAs in blastocysts. Dormant blastocysts in delayed implanting mice were activated by estradiol. Differential expression of 45 out of 238 miRNAs examined was found between the dormant and the activated blastocysts. Five of the nine members of the microRNA lethal-7 (let-7) family were down-regulated after activation. Human blastocysts also had a low expression of let-7 family. Forced-expression of a family member, let-7a in mouse blastocysts decreased the number of implantation sites (let-7a: 1.1±0.4; control: 3.8±0.4) in vivo, and reduced the percentages of blastocyst that attached (let-7a: 42.0±8.3%; control: 79.0±5.1%) and spreaded (let-7a: 33.5±2.9%; control: 67.3±3.8%) on fibronectin in vitro. Integrin-β3, a known implantation-related molecule, was demonstrated to be a target of let-7a by 3′-untranslated region reporter assay in cervical cancer cells HeLa, and Western blotting in mouse blastocysts. The inhibitory effect of forced-expression of let-7a on blastocyst attachment and outgrowth was partially nullified in vitro and in vivo by forced-expression of integrin-β3. This study provides the first direct evidence that let-7a is involved in regulating the implantation process partly via modulation of the expression of integrin-β3. (200 words).

Human endometrial CD98 is essential for blastocyst adhesion

Background

Understanding the molecular basis of embryonic implantation is of great clinical and biological relevance. Little is currently known about the adhesion receptors that determine endometrial receptivity for embryonic implantation in humans.

Methods and Principal Findings

Using two human endometrial cell lines characterized by low and high receptivity, we identified the membrane receptor CD98 as a novel molecule selectively and significantly associated with the receptive phenotype. In human endometrial samples, CD98 was the only molecule studied whose expression was restricted to the implantation window in human endometrial tissue. CD98 expression was restricted to the apical surface and included in tetraspanin-enriched microdomains of primary endometrial epithelial cells, as demonstrated by the biochemical association between CD98 and tetraspanin CD9. CD98 expression was induced in vitro by treatment of primary endometrial epithelial cells with human chorionic gonadotropin, 17-β-estradiol, LIF or EGF. Endometrial overexpression of CD98 or tetraspanin CD9 greatly enhanced mouse blastocyst adhesion, while their siRNA-mediated depletion reduced the blastocyst adhesion rate.

Conclusions

These results indicate that CD98, a component of tetraspanin-enriched microdomains, appears to be an important determinant of human endometrial receptivity during the implantation window.

Tetraspanin CD9 in bovine oocytes and its role in fertilization

This study was conducted in bovine to investigate whether CD9 (a member of the tetraspanin superfamily of proteins) is present on oocytes and whether it functions in sperm-oocyte binding and fusion. First, the presence of CD9 in bovine matured oocytes was examined by immunofluorescence with the anti-CD9 monoclonal antibody (mAb) and fluorescein isothiocyanate-conjugated goat anti-mouse antibody, and the results showed that CD9 was expressed on the plasma membrane of matured oocytes. Sperm binding and fusion with oocytes was then examined by in vitro fertilization. When the zona pellucida-free matured oocytes were fertilized, both sperm binding to ooplasma and sperm penetrating into oocytes were significantly (P<0.01) reduced in anti-CD9 antibody-treated oocytes (6.3 +/- 0.7 per oocyte and 41.6%, respectively) compared with untreated control oocytes (19.0 +/- 0.7 per oocyte and 81.3%, respectively), indicating that the anti-CD9 mAb potentially inhibits sperm-oocyte binding and fusion. These results demonstrated that the CD9 present on bovine matured oocytes is involved in sperm-oocyte interaction during fertilization.