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Cullin 3 (CUL3), a scaffold protein, assembles a large number of ubiquitin ligase complexes, similar to Skp1-Cullin 1-F-box protein complex. Several genetic models have shown that CUL3 is crucial for early embryonic development. Nevertheless, the role of CUL3 in human trophoblast function remains unclear. In this study, immunostaining revealed that CUL3 was strongly expressed in the villous cytotrophoblasts, the trophoblast column, and the invasive extravillous trophoblasts. Silencing CUL3 significantly inhibited the outgrowth of villous explant ex vivo and decreased invasion and migration of trophoblast HTR8/SVneo cells. Furthermore, CUL3 siRNA decreased pro-MMP9 activity and increased the levels of TIMP1 and 2. We also found that the level of CUL3 in the placental villi from pre-eclamptic patients was significantly lower as compared to that from their gestational age-matched controls. Moreover, in the lentiviral-mediated placenta-specific CUL3 knockdown mice, lack of CUL3 resulted in less invasive trophoblast cells in the maternal decidua. Taken together, these results suggest an essential role for CUL3 in the invasion and migration of trophoblast cells, and dysregulation of its expression may be associated with the onset of pre-eclampsia.

Transforming growth factor β (TGFβ) has been shown to be a multifunctional cytokine required for embryonic development and regulation of trophoblast cell behaviors. In the present study, a non-transformed cell-line representative of normal human trophoblast (NPC) was used to examine the effect of TGFβ1 on trophoblast cell adhesion and invasion. In vitro assay showed that TGFβ1 could significantly promote intercellular adhesion, while inhibiting cell invasion across the collagen I-coated filter. Reverse transcription (RT)-PCR and gelatin zymography demonstrated that TGFβ1 evidently repressed the mRNA expression and proenzyme production of matrix metalloproteinase (MMP)-9, but exerted no effect on mRNA expression and secretion of MMP-2. On the other hand, both the mRNA and protein expression of epithelial-cadherin and β-catenin were obviously upregulated by TGFβ1 in dose-dependent fashion, as revealed by RT-PCR and western-blot analysis. What is more, one of the critical TGFβ signaling molecules – Smad2 was notably phosphorylated in TGFβ1-treated NPC cells. The data indicates that cell invasion and adhesion are coordinated processes in human trophoblasts and that there exists paracrine regulation on adhesion molecules and invasion-associated enzymes in human placenta.

The present study was designed to investigate the localization and function of cytoplasmic dynein (dynein) during mouse oocyte meiosis and its relationship with two major spindle checkpoint proteins, mitotic arrest-deficient (Mad) 1 and Mad2. Oocytes at various stages during the first meiosis were fixed and immunostained for dynein, Mad1, Mad2, kinetochores, microtubules, and chromosomes. Some oocytes were treated with nocodazole before examination. Anti-dynein antibody was injected into the oocytes at germinal vesicle (GV) stage before the examination of its effects on meiotic progression or Mad1 and Mad2 localization. Results showed that dynein was present in the oocytes at various stages from GV to metaphase II and the locations of Mad1 and Mad2 were associated with dynein’s movement. Both Mad1 and Mad2 had two existing states: one existed in the cytoplasm (cytoplasmic Mad1 or cytoplasmic Mad2), which did not bind to kinetochores, while the other bound to kinetochores (kinetochore Mad1 or kinetochore Mad2). The equilibrium between the two states varied during meiosis and/or in response to the changes of the connection between microtubules and kinetochores. Cytoplasmic Mad1 and Mad2 recruited to chromosomes when the connection between microtubules and chromosomes was destroyed. Inhibition of dynein interferes with cytoplasmic Mad1 and Mad2 transportation from chromosomes to spindle poles, thus inhibits checkpoint silence and delays anaphase onset. These results indicate that dynein may play a role in spindle checkpoint inactivation.

Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder accompanied by chronic low-grade inflammation; its etiology is still undefined. This study investigated the expression of CXCL12, CXCR4, and CXCR7 in PCOS rats and their role in regulation of apoptosis. To accomplish this, we established an in vivo PCOS rat model and studied KGN cells (human ovarian granulosa cell line) in vitro. In PCOS rats, the ovarian expression of CXCL12, CXCR4, and CXCR7 was reduced, and the apoptosis rate of granulosa cells was increased, accompanied by decreased expression of BCL2 and increased expression of BAX and cleaved CASPASE3 (CASP3). We further showed that recombinant human CXCL12 treatment upregulated BCL2, downregulated BAX, and cleaved CASP3 in KGN cells to inhibit their apoptosis in a concentration-dependent manner; moreover, the effect of CXCL12 was weakened by CXCR4 antagonist AMD3100 and anti-CXCR7 neutralizing antibody. In conclusion, PCOS rats showed decreased CXCL12, CXCR4, and CXCR7 expression and increased apoptosis rate of ovarian granulosa cells. Further, in human KGN cells, CXCL12 regulated the expression of BAX, BCL2, and cleaved CASP3 to inhibit apoptosis through CXCR4- and CXCR7-mediated signal transmission. These findings may provide a theoretical and practical basis for illuminating the role of proinflammatory cytokines in the pathogenesis of PCOS.

Endometriosis (EMs) is an estrogen (E₂)-dependent inflammatory disorder. Although EMs is considered a benign disease, it presents with malignant characteristics, such as migration and invasion. An increasing number of studies have shown that aberrantly expressed circular RNAs (circRNAs) play an essential role in disease development and progression. However, the mechanisms by which circRNAs exert their pathological effects in EMs remain unclear. Hsa_circ_0001649, a novel cancer-associated circRNA, has been previously reported to be downregulated in several cancer types and related to cell migration and invasion. In the present study, real-time PCR (qRT-PCR) was carried out to measure hsa_circ_0001649 levels in human tissues, human primary endometrial stromal cells (ESCs) and a human endometrial stromal cell line (ThESCs). Matrix metalloproteinase 9 (MMP9) levels in ESCs and ThESCs were assessed by qRT-PCR and Western blotting, and the migration and invasion capacities of ThESCs were evaluated by transwell assay. As a result, hsa_circ_0001649 expression was significantly decreased in ectopic and eutopic endometrial samples compared with that in normal endometrial samples. E₂ decreased hsa_circ_0001649 expression but increased MMP9 expression in ESCs and ThESCs. Furthermore, ThESCs were more invasive under E₂ stimulation. However, these effects disappeared when ICI or hsa_circ_0001649 transfection was used. Collectively, our findings reveal that decreased hsa_circ_0001649 expression plays a role in E₂-increased MMP9 expression through E₂ receptors (ERs), which have critical functions in EMs.

Preeclampsia is a gestational hypertensive disease; however, preeclampsia remains poorly understood. Bioinformatics analysis was applied to find novel genes involved in the pathogenesis of preeclampsia and identified CLDN1 as one of the most differentially expressed genes when comparing patients with preeclampsia and healthy controls. The results of the qRT-PCR, Western blotting and immunohistochemistry experiments demonstrated that CLDN1 was significantly downregulated in the chorionic villi in samples from patients with preeclampsia. Furthermore, knockdown of CLDN1 in HTR-8/SVneo cells resulted in the inhibition of proliferation and induction of apoptosis, and overexpression of CLDN1 reversed these effects. In addition, RNA-seq assays demonstrated that the gene BIRC3 is potentially downstream of CLDN1 and is involved in the regulation of apoptosis. Knockdown of CLDN1 confirmed that the expression level of BIRC3 was obviously decreased and was associated with a significant increase in cleaved PARP. Interestingly, the apoptotic effect in CLDN1 knockdown cells was rescued after BIRC3 overexpression. Overall, these results indicate that a decrease in CLDN1 inhibits BIRC3 expression and increases cleaved PARP levels thus participating in the pathogenesis of preeclampsia.

Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. IFT172 is a component of the IFT complex. Global disruption of mouse Ift172 gene caused typical phenotypes of ciliopathy. Mouse Ift172 gene appears to translate two major proteins; the full-length protein is highly expressed in the tissues enriched in cilia and the smaller 130 kDa one is only abundant in the testis. In male germ cells, IFT172 is highly expressed in the manchette of elongating spermatids. A germ cell-specific Ift172 mutant mice were generated, and the mutant mice did not show gross abnormalities. There was no difference in testis/body weight between the control and mutant mice, but more than half of the adult homozygous mutant males were infertile and associated with abnormally developed germ cells in the spermiogenesis phase. The cauda epididymides in mutant mice contained less developed sperm that showed significantly reduced motility, and these sperm had multiple defects in ultrastructure and bent tails. In the mutant mice, testicular expression levels of some IFT components, including IFT20, IFT27, IFT74, IFT81 and IFT140, and a central apparatus protein SPAG16L were not changed. However, expression levels of ODF2, a component of the outer dense fiber, and AKAP4, a component of fibrous sheath, and two IFT components IFT25 and IFT57 were dramatically reduced. Our findings demonstrate that IFT172 is essential for normal male fertility and spermiogenesis in mice, probably by modulating specific IFT proteins and transporting/assembling unique accessory structural proteins into spermatozoa.

With tetraspanning topology, members of the membrane-spanning four-domain subfamily A (MS4A) may facilitate signaling or ion channel functions in many tissues. In this study, we report the cloning of a full-length cDNA from rat testis, designated Ms4a14 (Sp3111), which encodes the MS4A protein with 1139 amino acid residues. In situ hybridization and immunohistochemical analyses indicate that Ms4a14 is predominantly expressed from round spermatids to spermatozoa at specific stages in the rat testis at both the mRNA and protein level. Immunofluorescence analysis revealed that MS4A14 (SP3111) is located in the acrosome and the midpiece of the flagellum in mature sperm. Previously, we explored and reported the involvement of MS4A14 in reproductive functions, using antibody blockage during IVF and a transgenic RNA interference method in a mouse model. Our results suggested that MS4A14 is involved in fertilization and zygote division. As MS4A14 protein exists in mammals, such as humans, cows, dogs, and rodents, MS4A14 may play a ubiquitous role in mammalian reproduction.

In this study, we investigated the development, the cell number of the blastocyst, and apoptosis in rabbit nuclear transfer (NT) embryos derived from adult fibroblasts and cumulus cells as compared with embryos derived from in vivo fertilization and in vitro culture. The developmental rate and the total cell number of the blastocyst were significantly lower in NT embryos than in fertilized embryos (FEs). The type of donor cells did not affect the embryonic developmental rate and the total cell number of blastocysts in NT groups. The present study investigated the onset and the frequency of apoptosis in NT embryos and FEs by using a terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling (TUNEL) assay. The earliest positive TUNEL signals were detected at the eight-cell stage in NT embryos and at the morula stage in FEs. The apoptotic index of the total blastocysts, the inner cell mass and the trophoderm was greatly higher in the NT embryos than in FEs. Moreover, the apoptotic index of the blastocyst from fibroblasts was significantly higher than that of the blastocyst from cumulus cells.