The bovine endometrial epithelial cells promote the differentiation of trophoblast stem-like cells to binucleate trophoblast cells

Simple method for isolation and culture of primary buffalo (Bubalus bubalis) endometrial epithelial cells (pBuEECs) and its characterization using high throughput proteomics approach

Early embryonic mortality resulting from insufficient interaction between the embryo and the uterus leads to the failure of pregnancy in livestock animals. Thus, it is imperative to comprehend the multifaceted process of implantation at molecular levels, which requires synchronized feto-maternal interaction. The in-vitro models serve as valuable tools to investigate the specific stages of implantation. The present study was undertaken to develop a simple method to isolate and culture the primary buffalo endometrial epithelial cells (pBuEECs), followed by proteome profiling of the proliferating cells. Collagenase I was used to separate uterine epithelial cells (UECs) from the ipsilateral uterine horn, and then the cells were separated using a cell strainer. After being seeded on culture plates, UECs developed colonies with characteristic epithelial shape and expressed important markers such as cytokeratin 18 (KRT18), progesterone receptor (PGR), β-estrogen receptor (ESR1), and leukemia inhibitory factor (LIF), which were confirmed by PCR. The purity of epithelial cells was assessed using cytokeratin 18 immunostaining, which indicated approximately 99% purity in cultured cells. The proteome profiling of pBuEECs via high-throughput tandem mass spectrometry (MS), identified a total of 3383 proteins. Bioinformatics analysis revealed enrichment in various biological processes, including cellular processes, metabolic processes, biological regulation, localization, signaling, and developmental processes. Moreover, the KEGG pathway analysis highlighted associations with the ribosome, proteosome, oxidative phosphorylation, spliceosome, and cytoskeleton regulation pathways. In conclusion, these well characterized cells offer valuable in-vitro model to enhance the understanding of implantation and uterine pathophysiology in livestock animals, particularly buffaloes.

Understanding conceptus-maternal interactions: what tools do we need to develop?

Communication between the maternal endometrium and developing embryo/conceptus is critical to support successful pregnancy to term. Studying the peri-implantation period of pregnancy is critical as this is when most pregnancy loss occurs in cattle. Our current understanding of these interactions is limited, due to the lack of appropriate in vitro models to assess these interactions. The endometrium is a complex and heterogeneous tissue that is regulated in a transcriptional and translational manner throughout the oestrous cycle. While there are in vitro models to study endometrial function, they are static and 2D in nature or explant models and are limited in how well they recapitulate the in vivo endometrium. Recent developments in organoid systems, microfluidic approaches, extracellular matrix biology, and in silico approaches provide a new opportunity to develop in vitro systems that better model the in vivo scenario. This will allow us to investigate in a more high-throughput manner the fundamental molecular interactions that are required for successful pregnancy in cattle.

Conceptus-induced, interferon tau-dependent gene expression in bovine endometrial epithelial and stromal cells†

Bovine endometrium consists of epithelial and stromal cells that respond to conceptus interferon tau (IFNT), the maternal recognition of pregnancy (MRP) signal, by increasing expression of IFN-stimulated genes (ISGs). Endometrial epithelial and stromal-cell-specific ISGs are largely unknown but hypothesized to have essential functions during pregnancy establishment. Bovine endometrial epithelial cells were cultured in inserts above stromal fibroblast (SF) cells for 6 h in medium alone or with IFNT. The epithelial and SF transcriptomic response was analyzed separately using RNA sequencing and compared to a list of 369 DEGs recently identified in intact bovine endometrium in response to elongating bovine conceptuses and IFNT. Bovine endometrial epithelial and SF shared 223 and 70 DEGs in common with the list of 369 endometrial DEGs. Well-known ISGs identified in the epithelial and SF were ISG15, MX1, MX2, and OAS2. DEGs identified in the epithelial but not SF included a number of IRF molecules (IRF1, IRF2, IRF3, and IRF8), mitochondria SLC transporters (SLC25A19, SLC25A28, and SLC25A30), and a ghrelin receptor. Expression of ZC3HAV1, an anti-retroviral gene, increased specifically within the SF. Gene ontology analysis identified the type I IFN signaling pathway and activation of nuclear factor kappa B transcription factors as biological processes associated with the epithelial cell DEGs. This study has identified biologically relevant IFNT-stimulated genes within specific endometrial cell types. The findings provide critical information regarding the effects of conceptus IFNT on specific endometrial compartments during early developmental processes in cattle.

Anti-inflammatory Effect of Astragalin and Chlorogenic Acid on Escherichia coli-Induced Inflammation of Sheep Endometrial Epithelium Cells

Endometritis is one of the main diseases which harm sheep husbandry. Astragalin and chlorogenic acid (CGA) are common active ingredients of traditional Chinese medicine (TCM) with immunoprotective, antioxidant, and anti-inflammatory properties. In the present study, sheep endometrial epithelium cells (SEECs) were successfully purified and identified, and the in vitro inflammation model of SEECs induced by Escherichia coli (E. coli) was successfully established. To explore the effect of astragalin and CGA on the inflammation induced by E. coli and its potential mechanism, six groups were set up, namely, group C, M, astragalin, CGA, BAY, and STR. Cells in group C were incubated with DMEM/F12 for 6 h, while cells in group M, astragalin, CGA, BAY, and STR were incubated with DMEM/F12, astragalin, CGA, BAY, and STR for 3 h, respectively, followed by E. coli infection at a multiplicity of infection (MOI) of 1 E. coli per cell for 3 h. Subsequently, the cells and the supernatant were collected to detect the expression of genes in the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) pathway by ELISA, qPCR, and western blot. The results showed that E. coli could induce inflammation of SEECs in vitro, while astragalin and CGA could alleviate the inflammatory response induced by E. coli via inhibiting the activation of the TLR4/NF-κB signaling pathway, which provides a theoretical and experimental foundation for preventing sheep endometritis clinically.

Cytobrush: A tool for sequential evaluation of gene expression in bovine endometrium

Aims were to (i) compare specific transcript abundance between endometrial samples collected by transcervical biopsy and cytobrush and (ii) measure the abundance of endometrial transcripts involved in PGF2α synthesis in samples collected by cytobrush. In Experiment 1, endometrial samples were taken transcervically by cytobrush and biopsy 10 days after ovulation. Compared to biopsy samples, abundance of transcripts for MSTN, AKR1C4 and PGR was similar, VIM, FLT1 and PTGES was lower (p < .05) and KRT18 and CD3D was greater in cytobrush samples (p < .05). Thus, there was an enrichment of epithelial and immune cells in the cytobrush samples. In Experiment 2, endometrial samples were collected by cytobrush on days 10, 13, 16 and 19 after ovulation. Abundance of PGR2 mRNA was maximum on day 10 then decreased (p < .05). Abundance of ESR1 decreased gradually from day 10 to day 16 then increased again on day 19. The greatest abundance of OXTR was noted on day 19. The sequential alterations in abundance of these transcripts are consistent with the release of PGF2α associated with luteolysis. In summary, cytobrush sampling provides representative, physiologically relevant samples of the luminal epithelium in cattle.

The correlation between inflammatory injury induced by LPS and RAS in EpH4-Ev cells

Renin-angiotensin system (RAS) plays an important role of regulating inflammatory injury. However, it is not clear about the correlation between renin-angiotensin system (RAS) and inflammation induced by LPS in mammary gland cells. So immunofluorescence was performed to verify the ACE2 expression in mammary gland cells. MTT assay was performed to detect cell viability. ELISA was performed to detect cytokines in cell supernatant. Western Blot was performed to analyze RAS levels and ACE2 level change was observed by immunofluorescence. The TLR4 level and p65 phosphorylation were detected by Western Blot. The ACE2 protein intensively located on the cell membrane. According to the results of MTT assay and TNF-α level, the injury was evidently induced by high concentration LPS after 9h. The TNF-α, IL-6, IL-8, ACE, AT1R and AngII had an increasing expression with the rise of cell injury. In contrast, the MasR, Ang1-7 and ACE2 had a declining expression with the increase of cell injury degree. The TLR4 level and p65 phosphorylation in high concentration LPS group was significantly higher than that of control group. These results suggest that a valid inflammatory injury was induced after the cells were treated by high concentration of LPS for 9h. Meanwhile, the ACE/AngII/AT1R axis was activated and the ACE2/Ang1-7/MasR axis was depressed.