Transcript profiling of Elf5+/- mammary glands during pregnancy identifies novel targets of Elf5

Genetic variation in the OPN gene affects milk composition in Chinese Holstein cows

The aim of this study was to investigate the association between genotypes and haplotypes of OPN, and milk composition in dairy cows. A total of 317 Chinese Holstein cows were genotyped via DNA sequencing in this study. Three single nucleotide polymorphisms (SNPs), g.2916G > A, g.58675C > T and g.58899C > A, and eight haplotypes were identified. Of the eight possible haplotypes, four haplotypes i.e., Hap2 (ACC; 55.30%), Hap6 (GCC, 15.6%), Hap1 (ACA, 13.6%) and Hap4 (ATC, 5.70%), were considered to be major with a cumulative estimated frequency of >90%. Single markers (g.2916G > A and g.58899C > A) and Haplotype Hap6/4 were found to be associated with an increase in butter-fat percentage (p < 0.05). Taken together, our results provided evidence that polymorphisms in OPN are associated with milk composition, and could potentially be used for marker-assisted selection in Chinese Holstein cows.

Overexpression of E74-Like Factor 5 (ELF5) Inhibits Migration and Invasion of Ovarian Cancer Cells

Background

E74-like factor 5 (ELF5) plays a key role in the processes of cell differentiation, apoptosis, and occurrence of tumors. However, the effect of ELF5 on metastasis and invasion in human ovarian cancer remains poorly understood.

Material/Methods

Quantitative real-time polymerase chain reaction (qPCR) was performed to measure the expression of ELF5. The viability of cells was detected by cell counting kit (CCK-8). Cell apoptosis was tested by flow cytometry. Matrigel plug angiogenesis assay was employed to determine angiogenesis rate. The protein expression levels of vascular endothelial growth factor (VEGF), cleaved caspase-3, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), E-cadherin, N-cadherin, Snail, phosphoinositide 3 kinase (PI3K), phosphorylated (p)-PI3K, tyrosine kinase B (AKT), and phosphorylated (p)-AKT were determined by Western blot. Wound-healing assay and Transwell were used to determine invasion and migration.

Results

We found that expression of ELF5 was obviously decreased in ovarian cancer cell lines. The cells viability, invasion and metastasis were inhibited by overexpression ELF5. ELF5 suppressed angiogenesis rate and the expression of VEGF. Changes of the expressions of Bcl-2, cleaved caspase-3 and Bax showed that anti-apoptosis ability was improved by ELF5. ELF5 also repressed N-cadherin and Snail and increased E-cadherin. The expressions of p-PI3K and p-AKT were decreased by ELF5. Further study showed that IGF-I reversed the inhibitory effect of ELF5 on growth and metastasis of SKOV3 cells.

Conclusions

Overexpression of ELF5 promoted the apoptosis and reduced the migration and invasion of ovarian cancer cells; therefore, it could provide a new approach to gene treatment of ovarian carcinoma.

Molecular aspects of adipoepithelial transdifferentiation in mouse mammary gland

The circular, reversible conversion of the mammary gland during pregnancy and involution is a paradigm of physiological tissue plasticity. The two most prominent cell types in mammary gland, adipocytes and epithelial cells, interact in an orchestrated way to coordinate this process. Previously, we showed that this conversion is at least partly achieved by reciprocal transdifferentiation between mammary adipocytes and lobulo-alveolar epithelial cells. Here, we aim to shed more light on the regulators of mammary transdifferentiation. Using immunohistochemistry with cell type-specific lipid droplet-coating markers (Perilipin1 and 2), we show that cells with an intermediate adipoepithelial phenotype exist during and after pregnancy. Nuclei of cells with similar transitional structural characteristics are highly positive for Elf5, a master regulator of alveologenesis. In cultured adipocytes, we could show that transient and stable ectopic expression of Elf5 induces expression of the milk component whey acidic protein, although the general adipocyte phenotype is not affected suggesting that additional pioneering factors are necessary. Furthermore, the lack of transdifferentiation of adipocytes during pregnancy after clearing of the epithelial compartment indicates that transdifferentiation signals must emanate from the epithelial part. To explore candidate genes potentially involved in the transdifferentiation process, we devised a high-throughput gene expression study to compare cleared mammary fat pads with developing, contralateral controls at several time points during pregnancy. Incorporation of bioinformatic predictions of secretory proteins provides new insights into possible paracrine signaling pathways and downstream transdifferentiation factors. We discuss a potential role for osteopontin (secreted phosphoprotein 1 [Spp1]) signaling through integrins to induce adipoepithelial transdifferentiation.

Multi-tissue omics analyses reveal molecular regulatory networks for puberty in composite beef cattle

Puberty is a complex physiological event by which animals mature into an adult capable of sexual reproduction. In order to enhance our understanding of the genes and regulatory pathways and networks involved in puberty, we characterized the transcriptome of five reproductive tissues (i.e. hypothalamus, pituitary gland, ovary, uterus, and endometrium) as well as tissues known to be relevant to growth and metabolism needed to achieve puberty (i.e., longissimus dorsi muscle, adipose, and liver). These tissues were collected from pre- and post-pubertal Brangus heifers (3/8 Brahman; Bos indicus x 5/8 Angus; Bos taurus) derived from a population of cattle used to identify quantitative trait loci associated with fertility traits (i.e., age of first observed corpus luteum (ACL), first service conception (FSC), and heifer pregnancy (HPG)). In order to exploit the power of complementary omics analyses, pre- and post-puberty co-expression gene networks were constructed by combining the results from genome-wide association studies (GWAS), RNA-Seq, and bovine transcription factors. Eight tissues among pre-pubertal and post-pubertal Brangus heifers revealed 1,515 differentially expressed and 943 tissue-specific genes within the 17,832 genes confirmed by RNA-Seq analysis. The hypothalamus experienced the most notable up-regulation of genes via puberty (i.e., 204 out of 275 genes). Combining the results of GWAS and RNA-Seq, we identified 25 loci containing a single nucleotide polymorphism (SNP) associated with ACL, FSC, and (or) HPG. Seventeen of these SNP were within a gene and 13 of the genes were expressed in uterus or endometrium. Multi-tissue omics analyses revealed 2,450 co-expressed genes relative to puberty. The pre-pubertal network had 372,861 connections whereas the post-pubertal network had 328,357 connections. A sub-network from this process revealed key transcriptional regulators (i.e., PITX2, FOXA1, DACH2, PROP1, SIX6, etc.). Results from these multi-tissue omics analyses improve understanding of the number of genes and their complex interactions for puberty in cattle.

Elf5 regulates mammary gland stem/progenitor cell fate by influencing notch signaling

The transcription factor E74-like factor 5 (Elf5) functions downstream of the prolactin receptor signaling pathway and plays an important role in mammary gland development. Using conditional mouse knockouts, we have previously shown that Elf5-null mammary glands exhibit a complete failure of alveologenesis during pregnancy. The Elf5-null developmental phenotype is mediated through alteration in the expression of several critical genes involved in alveologenesis, particularly those belonging to the JAK/STAT pathway. Here, we demonstrate that in addition to regulating terminal differentiation of alveolar cells, Elf5 also plays a critical role in determining cell fate and in regulating the stem/progenitor function of the mammary epithelium. Targeted deletion of Elf5 in the mammary glands leads to accumulation of cell types with dual luminal/basal properties such as coexpression of K8 and K14 and an increase in CD61(+) luminal progenitor population during pregnancy. Further interrogation suggests that the abnormal increase in K14(+) K8(+) cells may represent the CD61(+) luminal progenitors blocked in differentiation. Remarkably, Elf5 deficiency in mammary epithelium also triggers an increase of adult mammary stem activity as evidenced by the accumulation of mammary stem cell (MaSC)-enriched cell population in both pregnant and virgin mice and further confirmed by mammosphere and transplantation assays. Additional support for this phenotype comes from the enriched MaSC gene signature based on transcriptomic analysis of the Elf5-null mammary gland. Finally, our biochemical studies suggest that Elf5 loss leads to hyperactivation of the Notch signaling pathway, which might constitute in part, the underlying molecular mechanism for the altered cell lineage decisions in Elf5-null mammary epithelial cells.

Elf5, hormones and cell fate

Recent elucidation of the stem and progenitor cell hierarchies that operate during normal tissue and organ development has provided a foundation for the development of new insights into the disease process. These hierarchies are established by genetic mechanisms, which specify and determine cell fate and act as cell-clade gatekeepers, upon which all multicellular organisms depend for viability. Perturbation of this gatekeeper function characterizes developmentally based diseases, such as cancer. Here, the emerging gatekeeper and master regulatory roles of the ETS transcription factor Elf5 in several diverse developmental scenarios is reviewed, and how this function intersects with hormonal and growth factor mediated regulation of these processes is shown.

The Ets transcription factor ELF5 functions as a tumor suppressor in the kidney

Renal cell carcinoma is an important clinical disease with poorly understood etiology. ELF5 is an epithelial-specific member of the Ets family of transcription factors, characterized by the 80 amino acid Ets domain that binds the purine-rich GGAA/T Ets motif found in the promoter regions of a variety of genes. Since ELF5 is highly expressed in kidney and has been postulated to function as a tumor suppressor, at least in the context of the breast, we investigated its role in kidney cancer. In renal cell carcinoma ELF5 expression was consistently decreased in tumor samples versus normal. ELF5 mRNA was decreased in 94% of lesions tested and ELF5 protein was undetectable in 40/40 kidney-derived carcinomas. Re-expression of the ELF5 gene in 786-O renal carcinoma cells suppressed their tumorigenic capacity in vitro and in vivo. This work is the first to suggest that ELF5 has tumor suppressor activity in the kidney.