Expression of wilms' tumor gene and protein localization during ovarian formation and follicular development in sheep

Differential expression of Wilms' tumour 1 gene in porcine urogenital organs during development

Wilms' tumour 1 gene (WT1) is essential for the development of mammalian urogenital system. However, the expression pattern of WT1 in the development of porcine urogenital organs is still unclear. Here, we examined the expression of WT1 mRNA and protein in porcine kidneys, ovaries and testes from embryonic days 35 and 60 (E35d, E60d, n = 3) to the newborn (0d, n = 4) and adult (210d, n = 3) stages, using real-time PCR and immunofluorescent staining. Real-time PCR analysis showed that porcine kidneys, ovaries and testes all expressed high level of WT1 mRNAs, especially in adult testes (p < 0.05 or 0.01 vs. kidney and ovary, respectively). Morphologically, characteristic microstructures of the kidneys, ovaries and testes were observed and discerned at all four stages. Immunofluorescently, WT1 expression was detected in a dynamic and context-specific pattern during the development of these organs. Taken together, porcine urogenital organs express relatively high levels of WT1 mRNA. Dynamical and context-specific expression profile of WT1 in these organs occurs during their development, implying its close association with the development and function of porcine kidney, ovary and testis.

The local regulation of folliculogenesis by members of the transforming growth factor superfamily and its relevance for advanced breeding programmes

Regulation of the growth and maturation of the ovarian follicle is critical for normal reproductive function. Alterations in this growth can lead to pathological conditions, such as cystic follicles, reduced oocyte quality, or an abnormal endocrine environment leading to poor fertility. Alterations in follicular growth also influence the number of follicles ovulating and thus can change litter size. Both endocrine factors, such as follicle stimulating hormone and luteinizing hormone, as well as local factors, are known to regulate follicular growth and development. This review will focus on the role of local factors in regulation of ovarian follicular growth in ruminants, with a focus on members of the transforming growth factor superfamily. The potential role of these factors in regulating proliferation, apoptosis, steroidogenesis and responsiveness to gonadotrophins will be considered.

Expression of Epithelial and Mesenchymal Differentiation Markers in the Early Human Gonadal Development

Expressions of cytokeratin 8 (CK8), vimentin, nestin, and alpha-smooth-muscle-actin (alpha-SMA) were analyzed in the developing gonads of 12, 5-9 week old (W) human conceptuses by immunohistochemistry and immunofluorescence. During the investigated period, the number of CK8 positive cells increased from 56% to 92% in the gonadal surface epithelium, from 50% to 60% in the stroma, and from 23% to 42% in the medulla. In the early fetal period, the cell expression of CK8 increased in all gonadal parts, whereas primordial germ cells (PGC) remained negative. The expression of vimentin increased in the gonad stroma (gs) from 73% to 88%, and in the surface epithelium from 18% to 97% until ninth W. The medulla had the highest expression of vimentin in the seventh to eighth W (93%). Vimentin and CK8 colocalized in the somatic cells, while some PGCs showed vimentin expression only. Initially, nestin was positive in the gonad surface epithelium (8%) and stroma (52%), however during further development it decreased to 1% and 33%, respectively. In the early fetal period, the nestin positive cells decreased from 44% to 31% in the gonad medulla. Alpha-SMA was positive only in the blood vessels and mesonephros. The described pattern of expression of intermediate filaments (IF) in developing human gonads suggests their role in the control of PGC apoptosis, early differentiation of gs cells and cell migration. Both epithelial and mesenchymal origins of follicular cells and possible epithelial-to-mesenchymal transition of somatic cells is proposed. Lastly, IF intensity expression varies depending on the cell type and developmental period analyzed. Anat Rec, 300:1315-1326, 2017. © 2017 Wiley Periodicals, Inc.

Expression profiles of Fsh-regulated ovarian genes during oogenesis in coho salmon

The function of follicle-stimulating hormone (Fsh) during oogenesis in fishes is poorly understood. Using coho salmon as a fish model, we recently identified a suite of genes regulated by Fsh in vitro and involved in ovarian processes mostly unexplored in fishes, like cell proliferation, differentiation, survival or extracellular matrix (ECM) remodeling. To better understand the role of these Fsh-regulated genes during oocyte growth in fishes, we characterized their mRNA levels at discrete stages of the ovarian development in coho salmon. While most of the transcripts were expressed at low levels during primary growth (perinucleolus stage), high expression of genes associated with cell proliferation (pim1, pcna, and mcm4) and survival (ddit4l) was found in follicles at this stage. The transition to secondary oocyte growth (cortical alveolus and lipid droplet stage ovarian follicles) was characterized by a marked increase in the expression of genes related to cell survival (clu1, clu2 and ivns1abpa). Expression of genes associated with cell differentiation and growth (wt2l and adh8l), growth factor signaling (inha), steroidogenesis (cyp19a1a) and the ECM (col1a1, col1a2 and dcn) peaked in vitellogenic follicles, showing a strong and positive correlation with transcripts for fshr. Other genes regulated by Fsh and associated with ECM function (ctgf, wapl and fn1) and growth factor signaling (bmp16 and smad5l) peaked in maturing follicles, along with increases in steroidogenesis-related gene transcripts. In conclusion, ovarian genes regulated by Fsh showed marked differences in their expression patterns during oogenesis in coho salmon. Our results suggest that Fsh regulates different ovarian processes at specific stages of development, likely through interaction with other intra- or extra-ovarian factors.

Effects of WT1 down-regulation on oocyte maturation and preimplantation embryo development in pigs

The Wilms' tumour 1 (WT1) gene originally identified as a tumour suppressor associated with WTs encodes a zinc finger-containing transcription factor that is expressed in multiple tissues and is an important regulator of cellular and organ growth, proliferation, development, migration and survival. However, there is a deficiency of data regarding the expression and function ofWT1during oocyte maturation and preimplantation embryonic development. Herein, we sought to define the expression characteristics and functions ofWT1during oocyte maturation and preimplantation embryonic development in pigs. We show thatWT1is expressed in porcine oocytes and at all preimplantation stages in embryos generated by ICSI. We then evaluated the effects of down-regulatingWT1expression at germinal vesicle and early ICSI stages using a recombinant plasmid (pGLV3-WT1-shRNA). Down-regulation ofWT1did not affect oocyte maturation but significantly decreased preimplantation embryonic development and increased apoptosis in blastocysts. These results indicate thatWT1plays important roles in the development of porcine preimplantation embryos.

Identification of ovarian genes regulated by follicle-stimulating hormone (Fsh) in vitro during early secondary oocyte growth in coho salmon

Follicle-stimulating hormone (Fsh) function in fishes is poorly understood. This study aimed to reveal Fsh-regulated genes in coho salmon previtellogenic ovarian follicles in vitro. Four suppression subtractive hybridization libraries were generated with RNA isolated from Fsh-treated and control follicles or follicle cell-enriched tissue fractions. Fsh induced steroidogenesis and dynamically upregulated several genes predominantly expressed in follicle cells, including WAP domain-containing protease, connexin 34.3, clusterin (clu1, clu2), fibronectin, wilms tumor 2-like, and influenza virus NS1A-binding protein a. Genes downregulated by Fsh included connective tissue growth factor, alcohol dehydrogenase 8-like, and serine/threonine-protein kinase pim-1. This study demonstrates for the first time in fishes that Fsh influences the expression of a unique suite of ovarian genes involved in processes like cell communication, survival and differentiation, and extracellular matrix remodeling. Collectively, these findings suggest that Fsh and/or steroids induce differentiation of granulosa cells and remodeling of the follicle in preparation for onset of vitellogenesis.

Identification of transcripts involved in meiosis and follicle formation during ovine ovary development

Background

The key steps in germ cell survival during ovarian development are the entry into meiosis of oogonies and the formation of primordial follicles, which then determine the reproductive lifespan of the ovary. In sheep, these steps occur during fetal life, between 55 and 80 days of gestation, respectively. The aim of this study was to identify differentially expressed ovarian genes during prophase I meiosis and early folliculogenesis in sheep.

Results

In order to elucidate the molecular events associated with early ovarian differentiation, we generated two ovary stage-specific subtracted cDNA libraries using SSH. Large-scale sequencing of these SSH libraries identified 6,080 ESTs representing 2,535 contigs. Clustering and assembly of these ESTs resulted in a total of 2,101 unique sequences depicted in 1,305 singleton (62.11%) and 796 contigs (37.9%) ESTs (clusters). BLASTX evaluation indicated that 99% of the ESTs were homologous to various known genes/proteins in a broad range of organisms, especially ovine, bovine and human species. The remaining 1% which exhibited any homology to known gene sequences was considered as novel. Detailed study of the expression patterns of some of these genes using RT-PCR revealed new promising candidates for ovary differentiation genes in sheep.

Conclusion

We showed that the SSH approach was relevant to determining new mammalian genes which might be involved in oogenesis and early follicle development, and enabled the discovery of new potential oocyte and granulosa cell markers for future studies. These genes may have significant implications regarding our understanding of ovarian function in molecular terms, and for the development of innovative strategies to both promote and control fertility.

WT1 expression in angiogenic tumours of the skin

AIMS

To determine the expression of WT1 in endothelial proliferations and tumours. Endothelial cells are derived from angioblasts which differentiate into bone marrow stem cells (BMSC). BMSC are characterized by the constitutive expression of the WT1 gene and we have postulated that its expression may be maintained during the differentiation of angioblasts to endothelial cells.

METHODS AND RESULTS

The expression of WT1 was studied in human umbilical vein-derived (HUVEC) and brain microvascular endothelial cells (HBME) as well as in a Kaposi sarcoma (KS) cell line in vitro. Forty-two human skin biopsy samples of endothelial proliferations and tumours were analysed for the protein expression of WT1 using the monoclonal antibodies for wt-WT1 (6F-H2) and its 17AA+ variant (2C12). WT1 expression was detectable in HUVEC and KS cells and all WT1 splice variants examined (17AA+/- KTS+/-) were detectable in KS cells, while the 17AA+/- and KTS- variants were present in HUVEC. Immunohistochemical analysis of the 42 human skin biopsy samples revealed cytoplasmic WT1 expression using wild-type specific antibody (6FH2) in microvessels, which is maintained during neoangiogenesis (inflammation, haemorrhage, peritumoral angiogenesis). Around one-third of haemangiomas (3/10) and non-HIV-Kaposi sarcomas (7/18) expressed the WT1 protein in the cytoplasm of tumour cells compared with its frequent expression in angiosarcomas (7/8) using the same antibody (6FH2). The nuclear 17AA+ isoform of WT1 was detectable at protein level in a small proportion of KS cases exclusively (3/7).

CONCLUSION

Our data suggest that WT1 protein expression is maintained during angiogenesis and malignant transformation of endothelial cells and can be considered as a new endothelial marker.

Formation of mammalian oocytes and their growth, differentiation and maturation within ovarian follicles

The limited knowledge on the regulation of oocyte formation, the different steps of folliculogenesis and the required conditions for oocytes to undergo proper growth, differentiation and maturation are major causes of the failure in obtaining viable offspring from in vitro cultured early oocytes from domestic animals and humans. This review highlights the factors that at present are known to be involved in the formation of mammalian oocytes and their growth, differentiation and maturation within ovarian follicles.