MicroRNAs are small regulatory RNAs that bind to the seeding regions within the 3’-untranslated region (3’-UTR) of their target transcripts to modulate transcript stability and/or inhibit protein translation. MicroRNA Let-7a belonging to the Lethal-7 (Let-7) family is down-regulated at the blastocyst stage, suggesting its suppression is crucial for embryo implantation. Yet, the underlying mechanism on how Let-7a modulates blastocyst implantation remains largely unknown. In silico analysis identified attachment related integrin beta-3, outgrowth related vav3, and the microRNA processing dicer, as Let-7a targets. Therefore, it is hypothesized that down-regulation of Let-7a promotes embryo implantation by stimulating these target proteins. Let-7a is down-regulated during blastulation and at 3-hour post-estradiol activation of the dormant blastocysts. Force-expression of Let-7a in mouse blastocysts suppressed blastocyst attachment, outgrowth on fibronectin-coated plates and compromised pregnancy in vivo. Dual luciferase assay using the 3’-UTR reporter constructs of the integrin beta-3, vav3, and dicer confirmed the interaction between Let-7a and the three targets. Force-expressing or inhibiting Let-7a expression in mouse blastocysts by electroporating the Let-7a precursor or inhibitor respectively illustrated post-transcriptional regulation of Let-7a on integrin beta-3 and vav3, and transcriptional regulation on dicer. Dormant blastocysts retrieved from the delayed implanting mice expressed high Let-7a levels, which was suppressed in the first 12-hours of estradiol activation. Concomitantly, dormant blastocysts expressed low levels of integrin beta-3, vav3, and dicer, yet, their protein expression was up-regulated from 3 hours-post estradiol activation. Furthermore, addition of integrin beta-3 antibody suppressed attachment of trophoblast spheroids (blastocyst surrogate) onto endometrial epithelial cells in a co-culture model and the outgrowth of the spheroids on fibronectin-coated plates. Knockdown of Vav3 with siRNA decreased blastulation, hatching, and outgrowth rates of the embryos in vitro. Although the loss of vav3 activities did not affect embryo implantation, it suppressed trophoblast migration on fibronectin-coated plates and invasion into collagen matrix. In contrast, force-expression of vav3 enhanced blastocyst outgrowth, and promoted cell proliferation. Blocking integrin beta-3 activities in the vav3 knock-down embryos further suppressed blastocyst outgrowth, suggesting the intertwining effect of the integrins and vav3. Dicer knock-down in mouse blastocysts decreased mature Let-7a expression and suppressed blastulation and hatching in vitro and implantation in vivo. Dicer knock-down in estradiol activated mouse blastocysts decreased the epidermal growth factor receptor expression and lowered the affinity of the embryos to EGF, and suppressed the implantation potential to a level similar to that of dormant blastocysts. Taken together, the suppression of Let-7a by estradiol up-regulates integrin beta-3, vav3, and dicer. The increased Itgb3 expression promotes blastocyst attachment and intertwined with the up-regulated vav3 expression to enhance blastocyst outgrowth. The increased vav3 expression further stimulates cell proliferation and confers blastocyst invasion into the collagen matrix. Dicer, by altering microRNA processing, facilitates blastulation and thereby embryo implantation. Thus, the loss of Let-7a biological activities during blastulation is crucial to enhance blastulation and stimulate trophoblast activities for successful embryo implantation. / published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Traditional Chinese medicine (TCM) plays an important role in the Chinese healthcare system for over five thousand years. It includes the use of herbal medicine, acupuncture, Tui Na (推拿), and diet therapy. TCM helps to maintain a balance of Yin-Yang (阴阳), Five Phases (五行), Meridians (经络) and Qi (气) inside the body. In practise, pregnant women take tocolytic drugs to tonify the blood and qi to provide a continuous supply of nutrients for baby. Traditional Chinese herbal medicines usually prescribed as a complex formula to produce synergistic or agonistic effect to maintain a well balance of the above components in human bodies. Moreover, TCM usually cannot produce immediate effect on patients, therefore, the efficacy of individual component remains largely unknown. This study aims to investigate whether Chinese tocolytic drug components could modulate fertility by affecting the in vitro spheroid (blastocyte surrogate) attachment process by using trophoblastic (JEG-3) and endometrial epithelial (Ishikawa) cells to mimic the embryo-endometrial implantation process. Nine Chinese herbal medicinal compounds (Atractylenolide I(白术内酯), Atractylenolide II(白术内酯II), Atractylenolide III(白术内酯III), Paeoniflorin(芍药苷), Albiflorin(芍药内酯苷), Nuzhenide(女贞子甙), Ecliptasaponin A(旱莲甙A), Wedelolactone(蟛蜞菊内酯) and Columbianadin(二氢欧山芹醇当归酸酯)) which are commonly found in traditional Chinese tocolytic drug formula were selected to study (1) the toxicity of the drugs on trophoblastic (JEG-3) and endometrial epithelial (Ishikawa) cells growth, (2) the effect of three tocolytic drugs (Atractylenolide I, Atractylenolide II and Atractylenolide III) on spheroid attachment, and (3) their effect of the expression of Wingless (Wnt) signaling molecules (Active-β-Catenin, Axin-2, β-catenin, E-cadherin, GSK-3β, and Mucin-1). It was found that the nine compounds, Atractylenolide I, Atractylenolide II, Atractylenolide III, Paeoniflorin, Albiflorin, Nuzhenide, Ecliptasaponin A, Wedelolactone and Columbianadin did not affect cell viability at 25μM, 25μM, 5μM, 0.2μM, 125μM, 125μM, 125μM, 5μM and 25μM, respectively, by cell proliferation assay. However, at these concentrations, the spheroid attachment was not significantly increased by Atractylenolide I, Atractylenolide II and Atractylenolide III. Interestingly, the protein expression of GSK-3β and Active-β-catenin were up-regulated by the three compounds in both cells and JEG-3 cells respectively. The expressions of Axin-2 and E-cadherin were up-regulated by Atractylenolide III in Ishikawa cells and Atractylenolide II in JEG-3 cells. Atractylenolide I and Atractylenolide III increase the Ishikawa cells expression of Active-β-catenin and β-catenin respectively and together suppress the JEG-3 cells Mucin-1 and β-catenin expression. In conclusion, the nine tocolytic compounds have different effect on cell proliferation. Atractylenolide I, Atractylenolide II and Atractylenolide III did not enhance the attachment rate of JEG-3 spheroid onto Ishikawa monolayer. However, they affected Wnt-signaling molecules expression, suggesting that they may modulate endometrial receptivity. Further experiments are needed to study their combined effect on co-culture and expression of Wnt-signaling molecules. / published_or_final_version / Obstetrics and Gynaecology / Master / Master of Medical Sciences

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Bibliography: leaves 175-203. / xxix, 203 leaves, [14] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates whether cytokines influence the development of the embryo prior to implantation. / Thesis (Ph.D.)--University of Adelaide, Depts. of Obstetrics and Gynaecology and Microbiology and Immunology, 1993