Epithelial and stromal cells of bovine endometrium have roles in innate immunity and initiate inflammatory responses to bacterial lipopeptides in vitro via Toll-like receptors TLR2, TLR1, and TLR6

Inflammatory uterine microenvironment in long-term infertility repeat breeder cows compared with normal fertile cows

The reproductive performance of lactating dairy cows is gradually declining, and one of the causes of this problem is the presence of long-term infertility repeat breeder cows (RBCs). The causes of RBCs are largely thought to be maternal factors, including the uterine environment. This study aimed to accurately investigate the uterine environment of RBCs using uterine tissue and fluid. Next, we investigated the effect of nobiletin in bovine endometrial epithelial cells to explore the possibility of improving the uterine environment of RBCs. Uterine fluid was collected by flushing the uterus and endometrial tissues were collected by biopsy on day 7 of the estrous cycle from both normal fertile cows and RBCs (n = 5 in each group). A comprehensive analysis of the uterus revealed that gene expression and altered pathways differed between normal fertile cows and RBCs. Especially, pathways of natural killer cell-mediated cytotoxicity, cell cycle, and calcium signaling pathway were picked up in the uterine tissues of RBCs. In the uterine fluid, the levels of lipopolysaccharide were higher in the RBC than in normal group (P = 0.08). In in vitro experiment, treatment with the uterine fluid from RBCs upregulated inflammation-related pathways and molecules such as interleukin-8 (IL-8) in bovine endometrial epithelial cells. The treatment with nobiletin suppressed IL-8 induced by the treatment with uterine fluid. In conclusion, the uterine environment of RBCs was found to be in inflammatory condition, causing the lower reproductive performance. It is necessary to develop methods to improve to the anti-inflammatory state in the uterine environment of RBCs.

Bioinformatics analysis to identify the relationship between human papillomavirus-associated cervical cancer, toll-like receptors and exomes: A genetic epidemiology study

INTRODUCTION

Genetic variants may influence Toll-like receptor (TLR) signaling in the immune response to human papillomavirus (HPV) infection and lead to cervical cancer. In this study, we investigated the pattern of TLR expression in the transcriptome of HPV-positive and HPV-negative cervical cancer samples and looked for variants potentially related to TLR gene alterations in exomes from different populations.

MATERIALS AND METHODS

A cervical tissue sample from 28 women, which was obtained from the Gene Expression Omnibus database, was used to examine TLR gene expression. Subsequently, the transcripts related to the TLRs that showed significant gene expression were queried in the Genome Aggregation Database to search for variants in more than 5,728 exomes from different ethnicities.

RESULTS

Cancer and HPV were found to be associated (p<0.0001). TLR1(p = 0.001), TLR3(p = 0.004), TLR4(221060_s_at)(p = 0.001), TLR7(p = 0.001;p = 0.047), TLR8(p = 0.002) and TLR10(p = 0.008) were negatively regulated, while TLR4(1552798_at)(p<0.0001) and TLR6(p = 0.019) were positively regulated in HPV-positive patients (p<0.05). The clinical significance of the variants was statistically significant for TLR1, TLR3, TLR6 and TLR8 in association with ethnicity. Genetic variants in different TLRs have been found in various ethnic populations. Variants of the TLR gene were of the following types: TLR1(5_prime_UTR), TLR4(start_lost), TLR8(synonymous;missense) and TLR10(3_prime_UTR). The "missense" variant was found to have a risk of its clinical significance being pathogenic in South Asian populations (OR = 56,820[95%CI:40,206,80,299]).

CONCLUSION

The results of this study suggest that the variants found in the transcriptomes of different populations may lead to impairment of the functional aspect of TLRs that show significant gene expression in cervical cancer samples caused by HPV.

Association between endometrial protein expression of IFN-γ and delayed conception after parturition in dairy cows

The cytokine context present in the reproductive tract of cows is closely involved in normal uterine functions, including the estrous cycle and the establishment and maintenance of pregnancy. However, the roles of some cytokines in the uterus, and their relation with reproductive performance remain to be elucidated. Thus, this study aimed to examine the protein expression of several cytokines such as TNFα, IL-6, IL-8, IFNγ, IL-4, and TGF-β3 in endometrial biopsies previous to conception, to evaluate the possible association with delayed conception in dairy cows. Protein expression levels were evaluated by immunohistochemistry. Results showed that the protein expression levels of TNFα, IL-6, IL-4 and TGF-β3 were not associated with the parturition-conception interval, whereas the high protein expression levels of IFNγ were associated with the parturition-conception interval. Finally, the low protein expression of IL-8 showed a statistical tendency to be associated with delayed conception. This is the first report about the protein expression of IFN-γ in the endometrium of dairy cows and also, this cytokine could enhance the favorable conditions to achieve an early pregnancy.

The roles of Braun Lipoprotein in inducing tolerance of bovine endometrium infected by Escherichia coli

Escherichia coli (E. coli), a Gram-negative bacterium, is the primary pathogen responsible for endometritis in dairy cattle. The outer membrane components of E. coli, namely lipopolysaccharide (LPS) and bacterial lipoprotein, have the capacity to trigger the host's innate immune response through pattern recognition receptors (PRRs). Tolerance to bacterial cell wall components, including LPS, may play a crucial role as an essential regulatory mechanism during bacterial infection. However, the precise role of Braun lipoprotein (BLP) tolerance in E. coli-induced endometritis in dairy cattle remains unclear. In this study, we aimed to investigate the impact of BLP on the regulation of E. coli infection-induced endometritis in dairy cattle. The presence of BLP was found to diminish the expression and release of proinflammatory cytokines (IL-8 and IL-6), while concurrently promoting the expression and release of the anti-inflammatory cytokine IL-10 in endometrial epithelial cells (EECs). Furthermore, BLP demonstrated the ability to impede the activation of MAPK (ERK and p38) and NF-κB (p65) signaling pathways, while simultaneously enhancing signaling through the STAT3 pathway in EECs. Notably, BLP exhibited a dual role, acting both as an activator of TLR2 and as a regulator of TLR2 activation in LPS- and E. coli-treated EECs. In E. coli-infected endometrial explants, the presence of BLP was noted to decrease the release of proinflammatory cytokines and the expression of HMGB1, while simultaneously enhancing the release of anti-inflammatory cytokines. Collectively, our findings provide evidence that the bacterial component BLP plays a protective role in E. coli-induced endometritis in dairy cattle.

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.

Homology Modeling, Molecular Dynamics Simulation, and Prediction of Bovine TLR2 Heterodimerization

Toll-like receptor 2 (TLR2) is a major membrane-bound receptor with ligand and species specificity that activates the host immune response. Heterodimerization of TLR2 with TLR1 (TLR2/1) or TLR6 (TLR2/6), triggered by ligand binding, is essential to initiating the signaling pathway. Bovine TLR2 (bTLR2) heterodimerization has not been defined yet compared with human and mouse TLR2s (hTLR2 and mTLR2). The aim of the present study was to model bovine TLRs (TLRs 1, 2 and 6) and create the heterodimeric forms of the bovine TLR2 using molecular dynamics (MD) simulations. We compared the intermolecular interactions in bTLR2/1-PAM3 and bTLR2/6-PAM2 with the hTLR2 and mTLR2 complexes through docking simulations and subsequent MD analyses. The present computational findings showed that bTLR2 dimerization could have a biological function and activate the immune response, similar to hTLR2 and mTLR2. Agonists and antagonists that are designed for hTLR2 and mTLR2 can target bTLR2. However, the experimental approaches to comparing the functional immune response of TLR2 across species were missing in the present study. This computational study provides a structural analysis of the bTLR2 interaction with bTLR1 and bTLR6 in the presence of an agonist/antagonist and reveals the three-dimensional structure of bTLR2 dimerization. The present findings could guide future experimental studies targeting bTLR2 with different ligands and lipopeptides.

Proteomic Approaches to Unravel the Molecular Dynamics of Early Pregnancy in Farm Animals: An In-Depth Review

Infertility is a major problem in farm animals, which has a negative economic effect on farm industries. Infertility can be defined as the inability of animals to achieve a successful pregnancy. Early pregnancy is crucial to establish a successful pregnancy, and it is reported that 70-80% and 20-30% of total embryonic loss occur in cattle and pigs, respectively, during the first month of pregnancy. The advanced high-throughput proteomics techniques provide valuable tools for in-depth understanding of the implantation process in farm animals. In the present review, our goal was to compile, assess, and integrate the latest proteomic research on farm animals, specifically focused on female reproduction, which involves endometrial tissues, uterine fluids, oviductal fluids, and microRNAs. The series of studies has provided in-depth insights into the events of the implantation process by unfolding the molecular landscape of the uterine tract. The discussed data are related to pregnant vs. non-pregnant animals, pregnancy vs. oestrous cycle, different days of the early pregnancy phase, and animals with uterine infections affecting reproduction health. Some of the studies have utilized non-invasive methods and in vitro models to decipher the molecular events of embryo-maternal interaction. The proteomics data are valuable sources for discovering biomarkers for infertility in ruminants and new regulatory pathways governing embryo-uterine interaction, endometrium receptivity, and embryonic development. Here, we envisage that the identified protein signatures can serve as potential therapeutic targets and biomarkers to develop new therapeutics against pregnancy diseases.

Transcriptome profiling of bovine endometrial epithelial cells induced by lipopolysaccharides in vitro

Endometritis is an inflammation of the surface of the endometrium that does not penetrate the submucosa and can cause infertility and increase the elimination rate in cows. Endometrial epithelial cells are the first barrier of the endometrium against foreign stimuli and bacterial infection. Understanding the genetic changes in stimulated endometrial epithelial cells will help in the efforts to prevent and treat endometritis. This study investigated changes in bovine endometrial epithelial (BEEC) gene expression induced by lipopolysaccharide (LPS)-induced inflammation and compared transcriptome-wide gene changes between LPS- and phosphate-buffered saline (PBS)- treated BEECs by RNA sequencing. Compared with the PBS group, the LPS group showed 60 differentially expressed genes (DEGs) (36 upregulated, 24 downregulated). Gene Ontology enrichment analysis revealed that most enrichment occurred during CXCR chemokine receptor binding, inflammatory response, and neutrophil migration. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed DEGs mainly concentrated in cytokine-cytokine receptor interactions; IL-17, tumor necrosis factor, NOD-like receptor, chemokine, Toll-like receptor, and nuclear factor-κB signaling pathways; and the cytoplasmic DNA sensing pathway. Moreover, results revealed that cytokines SAA3 and HP increased significantly after LPS treatment. These effects of LPS on BEECs transcriptome and the molecular mechanism of endometritis provide a basis for improved clinical treatment and novel drug development.

Plasma microRNAs as non-invasive biomarkers in bovine endometritis caused by Gram-negative and Gram-positive bacteria

The purpose was to identify differentially expressed plasma microRNAs (miRNAs) in cows with clinical and subclinical endometritis. In this study clinical endometritis (CE; n = 23) based on vaginal discharge score (VDS), subclinical endometritis (SCE; n = 17) based on VDS (0), and endometrial cytology (the presence of 8.00% polymorphonuclear neutrophils (PMN) on days 21-31 and 5.00% on days 41-51 days in milk (DIM) and healthy cows (n = 21) based on vaginal discharge score (0), and endometrial cytology (< 5.00% PMN on days 21 - 31 and < 5.00% on days 41 - 51 DIM) were selected. The results showed that the expression level of miR-146a was significantly higher in the CE (19.17-fold), and SCE (6.22-fold) groups than those of healthy cows. The relative transcript abundance of miR-223 was considerably down-regulated in the CE (0.26-fold) and SCE (0.06-fold) compared to the healthy cows. The expression levels of miR-146a and miR-223 were significantly higher in the CE group which could be caused by Gram-negative bacterial infection. Our results showed that the expression level of plasma miRNAs postpartum could be used as a reliable marker to distinguish between SCE, CE and healthy cows.

Use of intravaginal lactic acid bacteria prepartum as an approach for preventing uterine disease and its association with fertility of lactating dairy cows

The objective of this study was to evaluate the effects of the use of intravaginal probiotics prepartum on the incidence risk of metritis postpartum and conception risk after first artificial insemination (AI). A total of 606 Holstein cows were enrolled 3 wk before their expected calving date from 2 farms. Cows were randomly assigned to either receive a 2-mL dose of a combination of 3 lactic acid bacteria (probiotic treatment) washed with approximately 2 mL of a sterile saline solution, into the vaginal canal twice weekly until parturition, or no intervention (control). Metritis diagnoses were carried out on 6 and 12 d postpartum. Vaginal discharge and rectal temperature were assessed, and vaginal discharge was scored on a scale from 1 to 4, where 1 = clear and 4 = fetid, purulent discharge. Metritis was defined as cows having a vaginal discharge score of 4 with or without fever (rectal temperature ≥39.5°C) on either 6 or 12 d postpartum, or both. Cows were bred after a 60-d voluntary waiting period primarily via the detection of estrus using automated activity monitors; cows not found in estrus were enrolled onto timed AI protocols to receive first breeding before 100 DIM. Pregnancy diagnosis was carried out at d 35 ± 7 post-AI on both farms. Data were analyzed via ANOVA using linear mixed regression models and survival analysis using a Cox proportional hazard model. Total incidence risk of metritis was 23.7% and 34.4% on farm A and farm B, respectively. Overall, the incidence of metritis was not different between treatment groups (control: 41.6 ± 3.8%; probiotic: 38.6 ± 4.0%); however, an interaction by farm was detected, where the probiotic treatment reduced metritis on one farm but not on the other. Conception risk after first AI was not affected by treatment. However, we detected an interaction between parity and treatment, where multiparous cows receiving the probiotic treatment were more likely to become pregnant compared with multiparous cows within the control group (hazard ratio: 1.33; 95% confidence interval: 1.10-1.60); no effect of probiotic treatment was found on the hazard of pregnancy for primiparous cows. In addition, the probiotic treatment was associated with an increased proportion of cows being detected in estrus for the first AI postpartum. In conclusion, vaginal probiotic treatment applied during the 3 wk prepartum was associated with a decreased incidence of metritis on one farm but not the other, suggesting that farm management may be a key player influencing treatment efficacy. Overall, probiotic treatment was found to have only limited effects on fertility in the current study.

Inflammatory responses of bovine endometrial epithelial cells are increased under in vitro heat stress conditions

Cattle exposed to heat stress have reduced fertility, reduced milk production and increased incidence of postpartum uterine infection. Heat stress is suggested to alter immune function of cattle; however, the mechanisms underlying heat stress mediated uterine infection are unknown. We hypothesized that exposure of endometrial cells to heat stress would further increase expression of inflammatory mediators in response to bacterial components due to altered heat-shock protein expression. Bovine endometrial epithelial cells (BEND) were exposed to Escherichia coli lipopolysaccharide (LPS) or a synthetic triacylated lipopeptide (Pam3CSK4) under heat stress (41.0 °C) or thermoneutral (38.5 °C) conditions for 24 h. Exposure of BEND cells to LPS or Pam3CSK4 increased the expression of the proinflammatory mediators IL1B, IL6, and CXCL8 compared to control medium. However, exposure of BEND cells to heat stress increased LPS and Pam3CSK4 induced expression of IL1B compared to cells exposed to thermoneutral conditions, and expression of LPS induced IL6 was also increased when BEND cells were exposed to heat stress. To determine if heat shock proteins increased BEND cell expression of inflammatory mediators, HSP1A1 and HSF1 were targeted by siRNA knock down. Expression of HSP1A1 and HSF1 were reduced following siRNA knockdown; however, knockdown of HSP1A1 or HSF1 further increased heat stress mediated increased expression of inflammatory mediators. These data suggest that heat stress increased BEND cell inflammatory responses to bacterial components, while heat shock proteins HSP1A1 and HSF1 help to restrain inflammatory responses. These mechanisms may contribute to the increased incidence of uterine infection observed in cows under heat stress conditions.

ATP Induces Interleukin-8, Intracellular Calcium Release, and ERK1/2 Phosphorylation in Bovine Endometrial Cells, Partially through P2Y Receptors

The bovine endometrium has an important defensive role in the postpartum period that acts when an inflammatory process associated with tissue damage or infection by bacteria is produced. Endometrial cells release cytokines and chemokines that recruit inflammatory cells, which release danger-associated molecular patterns (DAMPs), such as adenosine triphosphate (ATP), and initiate and regulate the inflammatory response. However, the role of ATP in bovine endometrial cells is unclear. The aim of this study was to determine the effect of ATP on interleukin-8 (IL-8) release, intracellular calcium mobilization, ERK1/2 phosphorylation, and the role of P2Y receptors, in bovine endometrial cells. Bovine endometrial (BEND) cells were incubated with ATP and the IL-8 release was determined by the ELISA assay. ATP of 50 and 100 μM significantly increased IL-8 released in BEND cells (50 μM: 23.16 ± 3.82 pg/mL, p = 0.0018; 100 μM: 30.14 ± 7.43 pg/mL, p = 0.0004). ATP (50 μM) also induced rapid intracellular calcium mobilization in Fura-2AM-loaded BEND cells, as well as ERK1/2 phosphorylation (ratio 1.1 ± 0.04, p = 0.0049). Suramin (50 μM), a pan-antagonist of P2Y receptors, partially reduced the intracellular calcium mobilization, ERK1/2 phosphorylation (ratio 0.83 ± 0.08, p = 0.045), and IL-8 release (9.67 ± 0.02 pg/mL, p = 0.014) induced by ATP. Finally, BEND cells expressed higher mRNA levels of P2Y1 and P2Y2 purinergic subtype receptors, and lower levels of P2Y11 and P2Y12 receptors, as determined by RT-qPCR. In conclusion, these results showed that ATP activates pro-inflammatory responses in BEND cells, which are partially mediated via P2Y receptors, and BEND cells express the mRNA of subtypes of P2Y receptors, which could have a key role in bovine endometrial inflammation.

Prepartum heat stress in dairy cows increases postpartum inflammatory responses in blood of lactating dairy cows

Uterine diseases and heat stress (HS) are major challenges for the dairy cow. Heat stress alters host immune resilience, making cows more susceptible to the development of uterine disease. Although HS increases the incidence of uterine disease, the mechanisms by which this occurs are unclear. We hypothesize that evaporative cooling (CL) to alleviate HS in prepartum cows has carry-over effects on postpartum innate immunity. Nulliparous pregnant Holstein heifers were assigned to receive either forced CL that resulted in cool conditions (shade with water soakers and fans; n = 14) or to remain under HS conditions (barn shade only; n = 16) for 60 d prepartum. Postpartum, all cows were housed in a freestall barn equipped with shade, water soakers, and fans. Respiratory rate and rectal temperature during the prepartum period were greater in HS heifers compared with CL heifers, indicative of HS. Although milk production was decreased in HS cows compared with CL cows, the incidence of uterine disease and content of total or pathogenic bacteria in vaginal mucus on d 7 or d 21 postpartum was not affected by treatment. Whole blood was collected on d 21 and subjected to in vitro stimulation with lipopolysaccharide. Lipopolysaccharide-induced accumulation of IL-1β, IL-10, and MIP-1α was greater in blood collected from HS cows compared with CL cows. Our results imply that prepartum HS during late pregnancy has carry-over effects on postpartum innate immunity, which may contribute to the increased incidence of uterine disease observed in cows exposed to prepartum HS.

Macleaya cordata extract modulates inflammation via inhibition of the NF-κB and MAPK signaling pathways in porcine alveolar macrophages induced by Glaesserella parasuis

Glässer's disease in pigs is associated with infection by Glaesserella parasuis and is characterized by pneumonia-like symptoms, fibrinous polyserositis, polyarthritis, and meningitis. Macleaya cordata, a commonly used traditional Chinese medication, has been shown to have anti-inflammatory, antiviral, antioxidative, antimicrobial, insecticidal, and antitumor properties. However, the anti-inflammatory effects of M. cordata on G. parasuis stimulation are still poorly understood. This study explored the anti-inflammatory effects and mechanisms of M. cordata extract on G. parasuis-induced inflammatory responses, via the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, in porcine alveolar macrophages (PAMs). Porcine alveolar macrophages, when stimulated with G. parasuis, initiated transcription of interleukin (IL)-1α, IL-1β, IL-6, IL-8, and tumor necrosis factor alpha (TNF-α). Furthermore, p65, IκBα, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) phosphorylation were upregulated via the NF-κB and MAPK signaling pathways. However, treatment with M. cordata extract inhibited transcription of IL-1α, IL-1β, IL-6, IL-8, and TNF-α and reduced p65, IκBα, p38, ERK, and JNK phosphorylation, by inhibiting activation of the NF-κB and MAPK signaling pathways in PAMs induced by G. parasuis. These findings reveal that M. cordata extract can reverse the inflammatory effect initiated by G. parasuis in vitro and that it possesses significant immunosuppression activity; thus, it may offer a novel strategy for controlling and treating G. parasuis infection.

Effect of temporary cessation of milking and estradiol combination on the antimicrobial components in goat milk

A temporary cessation of milking is widely used in Japan to treat mastitis in dairy cows. Exogenous administration of estradiol (E2) is known to inhibit milk production in dairy cows. Therefore, we aimed to evaluate the effects of the temporary cessation of milking in combination with E2 administration on the antimicrobial components of goat milk. Twelve goats, divided into two groups-with and without E2 injection (E2 and control group, respectively), were subjected to cessation of milking in both udder halves for 3 d (day 0-2). Milk yield in the E2 group was significantly lower than that in the control group on days 7 to 10. The concentrations of cathelicidin-2, IgA, and lactoferrin in the E2 group were significantly higher than those in the control group. These results suggest that the temporary cessation of milking with simultaneous E2 administration leads to a higher concentration of certain antimicrobial components in milk than that observed after using cessation of milking alone. Thus, this combination may contribute to a stronger innate immune system and a faster recovery from mastitis, and might prove to be an alternative to antibiotic treatment upon further research.

Cortisol inhibits lipopolysaccharide-induced inflammatory response in bovine endometrial stromal cells via NF-κB and MAPK signaling pathways

Bovine uterine infection is commonly caused by Escherichia coli (E. coli). Elevated concentrations of plasma cortisol have been reported in postpartum cows. However, the direct role of cortisol in the inflammatory response of bovine endometrial stromal cells (BESCs) remains unclear. Therefore, the aim of the study was to explore the regulatory effect of cortisol on lipopolysaccharide (LPS)-induced inflammatory response in BESCs. Both the primary and immortalized BESCs were used in this study. BESCs were treated with cortisol (5, 15, and 30 ng/mL) in the presence of LPS. The mRNA expression of inflammatory cytokines and chemokines was detected using RT-qPCR. Western blot and immunofluorescence were used to analyze the activation of the NF-κB and MAPK signaling pathways. The results revealed that cortisol downregulated the LPS-induced overexpression of interleukin(IL)-1β, IL-6, IL-8, TNF-α, COX-2, iNOS in BESCs. Moreover, cortisol inhibited LPS-induced phosphorylation levels of IκB, p65, ERK1/2, JNK and p38, and p65 nuclear translocation in BESCs. These results indicated that cortisol inhibited LPS-induced inflammatory response in BESCs, which may be mediated by suppressing the NF-κB and MAPK signaling pathways.

Lactobacillus plantarum 17-5 attenuates Escherichia coli-induced inflammatory responses via inhibiting the activation of the NF-κB and MAPK signalling pathways in bovine mammary epithelial cells

Background

Mastitis is one of the most prevalent diseases and causes considerable economic losses in the dairy farming sector and dairy industry. Presently, antibiotic treatment is still the main method to control this disease, but it also brings bacterial resistance and drug residue problems. Lactobacillus plantarum (L. plantarum) is a multifunctional probiotic that exists widely in nature. Due to its anti-inflammatory potential, L. plantarum has recently been widely researched in complementary therapies for various inflammatory diseases. In this study, the apoptotic ratio, the expression levels of various inflammatory mediators and key signalling pathway proteins in Escherichia coli-induced bovine mammary epithelial cells (BMECs) under different doses of L. plantarum 17–5 intervention were evaluated.

Results

The data showed that L. plantarum 17–5 reduced the apoptotic ratio, downregulated the mRNA expression levels of TLR2, TLR4, MyD88, IL1β, IL6, IL8, TNFα, COX2, iNOS, CXCL2 and CXCL10, and inhibited the activation of the NF-κB and MAPK signalling pathways by suppressing the phosphorylation levels of p65, IκBα, p38, ERK and JNK.

Conclusions

The results proved that L. plantarum 17–5 exerted alleviative effects in Escherichia coli-induced inflammatory responses of BMECs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03355-9.

Lactobacillus rhamnosus GR-1 Alleviates Escherichia coli-Induced Inflammation via NF-κB and MAPKs Signaling in Bovine Endometrial Epithelial Cells

Escherichia coli counts as a major endometritis-causing pathogen among dairy cows, which lowered the economic benefits of dairy farming seriously. Probiotic consumption has been reported to impart beneficial effects on immunomodulation. However, the inflammatory regulation mechanism of probiotics on endometritis in dairy cows remains unexplored. The current work aimed to clarify the mechanism whereby Lactobacillus rhamnosus GR-1 (L. rhamnosus GR-1) resists bovine endometrial epithelial cells (BEECs) inflammatory injury induced by E. coli. The model of cellular inflammatory injury was established in the BEECs, which comes from the uterus of healthy dairy cows using E. coli. The outcome of L. rhamnosus GR-1 addition on inflammation was evaluated in BEECs with E. coli-induced endometritis. The underlying mechanisms of anti-inflammation by L. rhamnosus GR-1 were further explored in E. coli-stimulated BEECs. In accordance with the obtained results, the use L. rhamnosus GR-1 alone could not cause the change of inflammatory factors, while L. rhamnosus GR-1 could significantly alleviate the expression of E. coli-induced inflammatory factors. Based on further study, L. rhamnosus GR-1 significantly hindered the TLR4 and MyD88 expression stimulated by E. coli. Moreover, we observed that in BEECs, L. rhamnosus GR-1 could inhibit the E. coli-elicited expressions of pathway proteins that are associated with NF-κB and MAPKs. Briefly, L. rhamnosus GR-1 can effectively protect against E. coli-induced inflammatory response that may be closely related to the inhibition of TLR4 and MyD88 stimulating NF-κB and MAPKs.

The Antioxidant Role of Selenium via GPx1 and GPx4 in LPS-Induced Oxidative Stress in Bovine Endometrial Cells

This study investigated the antioxidant role of selenium (Se) in the form of selenomethionine (SLM) in LPS-induced oxidative stress via the glutathione peroxidase (GPx) enzymes and the Nrf2/HO-1 transcription factor. The impact of serum supplementation in culture media on GPxs was also studied. The bovine uterus is constantly exposed to exogenous pathogens postpartum, and the endometrium is the first contact against bacteria invasion. Endometritis is an inflammation of the endometrium and is brought about by bacterial lipopolysaccharide capable of inducing oxidative stress. The BEND cells were supplemented at the point of seeding with the following SLM concentrations 0, 100, 500, and 1000 nM for 48 h. BEND cells, cultured with or without SLM (100 nM), were initially incubated for 48 h, and then, we serum starved the SLM group for 24, 48, and 72 h. Similarly, an assay involving serum volume (0, 2, 5, and 10%) supplementation in culture media (v/v) with or without SLM (100 nM) was performed for 48 h. The BEND cells were also seeded into four experimental groups and cultured for an initial 48 h as follows: control, LPS (20 μg/mL), SLM (100 nM), and SLM + LPS groups followed by 6-h LPS treatment. The role of SLM in modulating the expressions of GPx1 and GPx4 and the Nrf2 transcription factor-related genes was assessed using qRT-PCR and Western blot techniques. The results showed serum starvation in the presence of SLM supplementation decreased the expression of GPx1 enzyme but increased GPx4 compared to the control. The addition of SLM to cell culture media in an FBS limiting condition improved the expressions of both GPx1 and GPx4. SLM supplementation promoted GPx enzymes' expressions in a serum-free media (0%) and at 2% FBS in media. However, it did not improve their expressions at 10% FBS in media than the untreated groups. Together, our data show the protective role of Se by regulating the expressions of GPx1 and GPx4 enzymes in BEND cells. It also shows that SLM promoted the expression of Nrf2 transcription factor-related genes at both the mRNA and protein levels in BEND cells during LPS stimulation.

Bovine endometrial cells do not mount an inflammatory response to Leptospira

Leptospirosis causes abortion, premature birth, and stillbirth in cattle, but the mechanisms remain unclear. Infected cattle shed Leptospira intermittently and present a range of clinical symptoms, making diagnosis difficult. The primary route of Leptospira transmission in any animal is the colonization of the renal tubule and excretion by urine; however, Leptospira can also colonize the female reproductive tract of cows and can be transmitted by semen. Vaccination against Leptospira in the US is routine in cattle, but immunity is not guaranteed. The cell wall of Leptospira contains toll-like receptor agonists including peptidoglycan and lipopolysaccharide. The capacity of Leptospira to initiate an innate inflammatory response from uterine endometrial cells is unknown but may be a cause of reproductive failure. Using cell culture, we tested the capacity of bovine endometrial epithelial cells or human monocytes to elicit an inflammatory response to Leptospira borgpetersenii serovar Hardjo strain TC273. Cells were exposed to either heat-killed Leptospira, Leptospira outer membrane, Escherichia coli lipopolysaccharide, Pam3CSK4 or medium alone for 2 to 24 h. Exposure of bovine endometrial epithelial cells or human monocytes to heat-killed Leptospira or Leptospira outer membrane did not induce the expression of IL1A, IL1B, IL6, or CXCL8, while exposure to E. coli lipopolysaccharide or Pam3CSK4 increased the expression of IL1A, IL1B, IL6, and CXCL8 compared to control cells. This data suggest that Leptospira does not trigger a classical inflammatory response in endometrial cells. Understanding the interaction between Leptospira and the female reproductive tract is important in determining the mechanisms of Leptospirosis associated with reproductive failure.

Lay summary

Cows infected with the Leptospira have abortion and stillbirth. It is not known how Leptospira causes pregnancy failure in the cow. We tested if Leptospira causes inflammation in cells of the uterus which triggers pregnancy failure. We collected cells from the uterus of healthy cows at the abattoir and placed them into culture with Leptospira and measured the expression of genes associated with inflammation. To our surprise, cells of the uterus did not respond to Leptospira; however, the same cells did respond to other disease-causing bacteria found in the uterus. This suggests that cells of the uterus can recognize bacteria and produce an inflammatory reaction but not in response to Leptospira. This finding suggests the immune system of the uterus cannot detect Leptospira which may go on to cause reproductive failure in cows. Understanding how Leptospira interact with cells of the uterus will help reduce pregnancy failure of cows with leptospirosis.

Nrf2/HO-1 pathway is involved the anti-inflammatory action of intrauterine infusion of platelet-rich plasma against lipopolysaccharides in endometritis

OBJECTIVE(S)

Endometritis is the inflammatory response of the uterine lining which is linked to infertility. Administration of platelet-rich plasma (PRP) represents a well-recommended strategy for the treatment of endometrium-associated infertility. In this study, we set to characterize the role and molecular mechanism of PRP intrauterine infusion in mice with endometritis.

METHODS

A mouse model of endometritis was established using lipopolysaccharide (LPS). Mouse endometrial epithelial cells were obtained in primary culture. PRP-treated cells were assayed for proliferative and apoptotic activities. Moreover, iNOS expression and chemokine and inflammatory factor contents in cells were assessed using RT-qPCR and ELISA. The mice were subjected to PRP intrauterine infusion. The expression of genes related to uterine development was analyzed by qPCR and the ki-67 content and caspase-3 activation in endometrial tissues were examined by immunohistochemistry. Finally, the Nrf2/HO-1 pathway activity in tissues was examined by Western blot.

RESULTS

LPS induced inflammatory cell recruitment and tissue damage in the endometrium of mice, along with significantly increased levels of inflammatory and chemokine factors. PRP significantly enhanced endometrial epithelial cell activity, decreased apoptosis, and reduced inflammatory factor secretion. In addition, PRP intrauterine infusion significantly increased the expression of genes related to uterine development, promoted tissue proliferation, decreased apoptosis, and diminished inflammatory response in endometrial tissues of mice. PRP intrauterine infusion significantly elevated Nrf2/HO-1 pathway activity in endometrial epithelial cells and tissues.

CONCLUSION

PRP intrauterine infusion significantly inhibited endometrial cell injury and alleviated the inflammatory response through activating the Nrf2/HO-1 pathway.

Integrated Network Analysis to Identify Key Modules and Potential Hub Genes Involved in Bovine Respiratory Disease: A Systems Biology Approach

Background: Bovine respiratory disease (BRD) is the most common disease in the beef and dairy cattle industry. BRD is a multifactorial disease resulting from the interaction between environmental stressors and infectious agents. However, the molecular mechanisms underlying BRD are not fully understood yet. Therefore, this study aimed to use a systems biology approach to systematically evaluate this disorder to better understand the molecular mechanisms responsible for BRD. Methods: Previously published RNA-seq data from whole blood of 18 healthy and 25 BRD samples were downloaded from the Gene Expression Omnibus (GEO) and then analyzed. Next, two distinct methods of weighted gene coexpression network analysis (WGCNA), i.e., module-trait relationships (MTRs) and module preservation (MP) analysis were used to identify significant highly correlated modules with clinical traits of BRD and non-preserved modules between healthy and BRD samples, respectively. After identifying respective modules by the two mentioned methods of WGCNA, functional enrichment analysis was performed to extract the modules that are biologically related to BRD. Gene coexpression networks based on the hub genes from the candidate modules were then integrated with protein-protein interaction (PPI) networks to identify hub-hub genes and potential transcription factors (TFs). Results: Four significant highly correlated modules with clinical traits of BRD as well as 29 non-preserved modules were identified by MTRs and MP methods, respectively. Among them, two significant highly correlated modules (identified by MTRs) and six nonpreserved modules (identified by MP) were biologically associated with immune response, pulmonary inflammation, and pathogenesis of BRD. After aggregation of gene coexpression networks based on the hub genes with PPI networks, a total of 307 hub-hub genes were identified in the eight candidate modules. Interestingly, most of these hub-hub genes were reported to play an important role in the immune response and BRD pathogenesis. Among the eight candidate modules, the turquoise (identified by MTRs) and purple (identified by MP) modules were highly biologically enriched in BRD. Moreover, STAT1, STAT2, STAT3, IRF7, and IRF9 TFs were suggested to play an important role in the immune system during BRD by regulating the coexpressed genes of these modules. Additionally, a gene set containing several hub-hub genes was identified in the eight candidate modules, such as TLR2, TLR4, IL10, SOCS3, GZMB, ANXA1, ANXA5, PTEN, SGK1, IFI6, ISG15, MX1, MX2, OAS2, IFIH1, DDX58, DHX58, RSAD2, IFI44, IFI44L, EIF2AK2, ISG20, IFIT5, IFITM3, OAS1Y, HERC5, and PRF1, which are potentially critical during infection with agents of bovine respiratory disease complex (BRDC). Conclusion: This study not only helps us to better understand the molecular mechanisms responsible for BRD but also suggested eight candidate modules along with several promising hub-hub genes as diagnosis biomarkers and therapeutic targets for BRD.

Oxysterols protect bovine endometrial cells against pore-forming toxins from pathogenic bacteria

Many species of pathogenic bacteria secrete toxins that form pores in mammalian cell membranes. These membrane pores enable the delivery of virulence factors into cells, result in the leakage of molecules that bacteria can use as nutrients, and facilitate pathogen invasion. Inflammatory responses to bacteria are regulated by the side-chain-hydroxycholesterols 27-hydroxycholesterol and 25-hydroxycholesterol, but their effect on the intrinsic protection of cells against pore-forming toxins is unclear. Here, we tested the hypothesis that 27-hydroxycholesterol and 25-hydroxycholesterol help protect cells against pore-forming toxins. We treated bovine endometrial epithelial and stromal cells with 27-hydroxycholesterol or 25-hydroxycholesterol, and then challenged the cells with pyolysin, which is a cholesterol-dependent cytolysin from Trueperella pyogenes that targets these endometrial cells. We found that treatment with 27-hydroxycholesterol or 25-hydroxycholesterol protected both epithelial and stomal cells against pore formation and the damage caused by pyolysin. The oxysterols limited pyolysin-induced leakage of potassium and lactate dehydrogenase from cells, and reduced cytoskeletal changes and cytolysis. This oxysterol cytoprotection against pyolysin was partially dependent on reducing cytolysin-accessible cholesterol in the cell membrane and on activating liver X receptors. Treatment with 27-hydroxycholesterol also protected the endometrial cells against Staphylococcus aureus α-hemolysin. Using mass spectrometry, we found 27-hydroxycholesterol and 25-hydroxycholesterol in uterine and follicular fluid. Furthermore, epithelial cells released additional 25-hydroxycholesterol in response to pyolysin. In conclusion, both 27-hydroxycholesterol and 25-hydroxycholesterol increased the intrinsic protection of bovine endometrial cells against pore-forming toxins. Our findings imply that side-chain-hydroxycholesterols may help defend the endometrium against pathogenic bacteria.

Beta-endorphin inhibits the inflammatory response of bovine endometrial cells through δ opioid receptor in vitro

Postpartum uterine infections are common reproductive diseases in postpartum cows. Evidence has shown that plasma β-endorphins increase during bovine uterine inflammation. However, the effect of β-endorphins on the inflammatory response in bovine endometrium has not been clarified. The aim of this study was to investigate the effect of β-endorphins on the inflammatory response of bovine endometrial epithelial and stromal cells, and to explore the possible mechanism. The cells were treated with E. coli lipopolysaccharide (LPS) to simulate inflammation, which was characterized by the significant activation of NF-κB signaling pathway and the increased gene expression of the downstream proinflammatory cytokines (approximately 1.2- to 15-fold increase, P < 0.05). By using Western blot and qPCR techniques, we found that β-endorphins inhibited the key protein expression of NF-κB pathway, and the gene expressions of TNF, IL1B, IL6, CXCL8, nitric oxide synthase 2, and prostaglandin-endoperoxide synthase 2 (P < 0.05). The co-treatment of β-endorphins and opioid antagonists showed that the anti-inflammatory effect of β-endorphins could be blocked (P < 0.05) by non-selective opioid antagonist naloxone or δ opioid receptor antagonist ICI 154129, but not the μ opioid receptor antagonist CTAP (P > 0.05). In conclusion, β-endorphins may inhibit the inflammatory response of bovine endometrial epithelial and stromal cells through δ opioid receptor.

Uterine infection alters the transcriptome of the bovine reproductive tract three months later

Infection of the postpartum uterus with pathogenic bacteria is associated with infertility months later in dairy cattle. However, it is unclear whether these bacterial infections lead to long-term changes in the reproductive tract that might help explain this infertility. Here we tested the hypothesis that infusion of pathogenic bacteria into the uterus leads to changes in the transcriptome of the reproductive tract 3 months later. We used virgin Holstein heifers to avoid potential confounding effects of periparturient problems, lactation, and negative energy balance. Animals were infused intrauterine with endometrial pathogenic bacteria Escherichia coli and Trueperella pyogenes (n = 4) and compared with control animals (n = 6). Three months after infusion, caruncular and intercaruncular endometrium, isthmus and ampulla of the oviduct, and granulosa cells from ovarian follicles >8 mm diameter were profiled by RNA sequencing. Bacterial infusion altered the transcriptome of all the tissues when compared with control. Most differentially expressed genes were tissue specific, with 109 differentially expressed genes unique to caruncular endometrium, 57 in intercaruncular endometrium, 65 in isthmus, 298 in ampulla, and 83 in granulosa cells. Surprisingly, despite infusing bacteria into the uterus, granulosa cells had more predicted upstream regulators of differentially expressed genes than all the other tissues combined. In conclusion, there were changes in the transcriptome of the endometrium, oviduct and even granulosa cells, 3 months after intrauterine infusion of pathogenic bacteria. These findings imply that long-term changes throughout the reproductive tract could contribute to infertility after bacterial infections of the uterus.

Modulation of Bovine Endometrial Cell Receptors and Signaling Pathways as a Nanotherapeutic Exploration against Dairy Cow Postpartum Endometritis

Simple Summary

The provision of updated information on the molecular pathogenesis of bovine endometritis with host-pathogen interactions and the possibility of exploring the cellular sensors mechanism in a nanotechnology-based drug delivery system against persistent endometritis were reported in this review. The mechanism of Gram-negative bacteria and their ligands has been vividly explored, with the paucity of research detail on Gram-positive bacteria in bovine endometritis. The function of cell receptors, biomolecules proteins, and sensors were reportedly essential in transferring signals into cell signaling pathways to induce immuno-inflammatory responses by elevating pro-inflammatory cytokines. Therefore, understanding endometrial cellular components and signaling mechanisms across pathogenesis are essential for nanotherapeutic exploration against bovine endometritis. The nanotherapeutic discovery that could inhibit infectious signals at the various cell receptors and signal transduction levels, interfering with transcription factors activation and pro-inflammatory cytokines and gene expression, significantly halts endometritis.

Abstract

In order to control and prevent bovine endometritis, there is a need to understand the molecular pathogenesis of the infectious disease. Bovine endometrium is usually invaded by a massive mobilization of microorganisms, especially bacteria, during postpartum dairy cows. Several reports have implicated the Gram-negative bacteria in the pathogenesis of bovine endometritis, with information dearth on the potentials of Gram-positive bacteria and their endotoxins. The invasive bacteria and their ligands pass through cellular receptors such as TLRs, NLRs, and biomolecular proteins of cells activate the specific receptors, which spontaneously stimulates cellular signaling pathways like MAPK, NF-kB and sequentially triggers upregulation of pro-inflammatory cytokines. The cascade of inflammatory induction involves a dual signaling pathway; the transcription factor NF-κB is released from its inhibitory molecule and can bind to various inflammatory genes promoter. The MAPK pathways are concomitantly activated, leading to specific phosphorylation of the NF-κB. The provision of detailed information on the molecular pathomechanism of bovine endometritis with the interaction between host endometrial cells and invasive bacteria in this review would widen the gap of exploring the potential of receptors and signal transduction pathways in nanotechnology-based drug delivery system. The nanotherapeutic discovery of endometrial cell receptors, signal transduction pathway, and cell biomolecules inhibitors could be developed for strategic inhibition of infectious signals at the various cell receptors and signal transduction levels, interfering on transcription factors activation and pro-inflammatory cytokines and genes expression, which may significantly protect endometrium against postpartum microbial invasion.

Hemodynamic changes in cytokines, chemokines, acute phase proteins and prostaglandins in mares with subclinical endometritis

Apparently healthy mares with conception failure or embryonic loss may have subclinical endometritis (SE). Our objective was to document evidence of systemic immune responses against SE in mares. In apparently healthy (control) mares as well as those with chronic endometritis (ChE) or subacute suppurative endometritis (SSE), both considered classes of SE, serum concentrations of cytokines (IL-1β, IL-6, IL-10 and TNF_-α), chemokines (IL-8), acute phase protein (SAA), and plasma concentrations of prostaglandins (PGF_2α and PGE₂) were measured using validated enzyme linked immunoassays (EIA). Mixed-breed mares of known reproductive history, were used. Based on an endometrial cytological examination, mares were allocated into the following groups: healthy (control), ChE, and SSE (12, 26 and 11 mares, respectively). Serum concentrations of IL-6, IL-8 and IL-10 and plasma PGF_2α concentrations were increased (P < 0.01) in mares with SSE compared to healthy mares. Furthermore, serum concentrations of IL-6 (P < 0.05) and IL-10 (P < 0.05) were elevated in the ChE group compared to the healthy group whereas serum SAA (P < 0.01) and plasma PGE₂ (P < 0.05) were higher in healthy mares compared to ChE and SSE mares. However, serum concentrations of IL-1β and TNF_-α were not significantly different among groups. In conclusion, there were two novel findings: (1) development of serum testing for a set of biochemical markers has promise to explore the pathogenesis of inflammation in mares with SE; and (2) none of the individual biomarkers studied, excluding IL-8, was a significant predictor of SE. However, serum IL-6:IL-10 and IL-6:TNF_-α concentrations, as well as plasma PGE₂:PGF_2α ratios, may yield a novel diagnostic marker for chronic subclinical endometritis.

MicroRNA: Could It Play a Role in Bovine Endometritis?

Endometritis in dairy cows is a major economic problem worldwide; without advances in lifestyle management and drug treatment, it causes high morbidity and death. Micro ribonucleic acid (miRNAs) these days is seen as an important part of gene control networks. It is a class of small nucleotides 20-25, single-stranded RNA molecules. In endometritis, the inflammatory response caused by the gram-negative bacteria Escherichia coli (E. coli) alters the expression of miRNA which can regulate the innate immune system. This manuscript reviews (1) the interaction of miRNAs with the signaling of NF-κB and dysregulation of miRNAs and NF-κB activity in endometritis and (2) the activity of miR-let-7c, miR-148a, and miR-488 in NF-κB activation and their effect on endometritis. Cows with reduced immunity are more vulnerable to transition diseases, such as endometritis. During post-partum, cows undergo stress, metabolic disorders, hormonal imbalance, negative energy balance, and changes in diet. One of the many categories of regulatory molecules, which explain its natural function and pathological impact on NF-κB dysregulation, is important to inform the complexity of the immune system and to develop treatments for endometritis. It shows that miRNAs could have multiple applications in veterinary medicine. Nevertheless, a comprehensive study of is essential which should be aimed at exploring the role of microRNA at physiological level and its effect due to dysfunction and dysregulation.

Activation of alpha7 nicotinic acetylcholine receptor protects bovine endometrial tissue against LPS-induced inflammatory injury via JAK2/STAT3 pathway and COX-2 derived prostaglandin E2

Bovine endometritis is one of the major postpartum diseases associated with infertility and subfertility, decreasing the benefit of dairy industry. It is important to develop alternate therapies for endometritis in the context of drug residues in the milk and hormone disorder in the estrous cycle. α7 nicotine acetylcholine receptor has been identified as the core of 'cholinergic anti-inflammatory pathway (CAP)', which is a potential drug target to inflammatory diseases. However, there has been still no study on its anti-inflammatory effects and mechanism on lipopolysaccharide (LPS)-induced bovine endometritis. This study aimed to demonstrate the underlying anti-inflammatory effects and mechanism of α7-nACh receptor on LPS-induced inflammation in bovine endometrial tissues cultured in vitro. The results suggested that activation of α7-nACh receptor significantly suppressed the mRNA expression levels of interleukin 1β (IL-1β), IL-6, IL-8, and tumor necrosis factor alpha (TNF-α) in bovine endometrial tissues. Western blot and enzyme-linked immunosorbent assay (ELISA) detection results showed that activation of α7-nACh receptor inhibited LPS-induced phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). Moreover, α7-nACh receptor agonist decreased the expression of cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase-1(mPGES-1), as well as prostaglandin E₂ (PGE₂) secretion. Interestingly, in COX-2 inhibition experiment, activation of α7-nACh receptor increased COX-2 expression and PGE₂ production, compared with COX-2 inhibitor treatment. In conclusion, activation of the cholinergic system through α7-nACh receptor agonist has suppressed inflammation of bovine endometrial tissues via JAK2/STAT3 pathway and potential COX-2-derived PGE₂.

Isolation, Culture, and Characterization of Primary Bovine Endometrial, Epithelial, and Stromal Cells for 3D In Vitro Tissue Models

Efficient isolation, characterization, and culture of endometrial epithelial cells and stromal fibroblasts from calf uteri collected at the slaughterhouse is key to develop useful 3D culture tissue models to investigate uterine physiology and pathology without the need of performing invasive procedures to recover tissue samples.Here we provide a detail methodology that gives consistently pure and viable populations of distinct primary bovine endometrial cells.

TLR4-Associated IRF-7 and NFκB Signaling Act as a Molecular Link Between Androgen and Metformin Activities and Cytokine Synthesis in the PCOS Endometrium

CONTEXT

Low-grade chronic inflammation is commonly seen in polycystic ovary syndrome (PCOS) patients with elevated levels of inflammatory cytokines in the endometrium.

OBJECTIVE

This work aimed to increase the limited understanding of the mechanisms underlying cytokine synthesis and increased endometrial inflammation in PCOS patients.

METHODS

Endometrial biopsy samples were collected from non-PCOS (n = 17) and PCOS (n = 22) patients either during the proliferative phase of the menstrual cycle or with hyperplasia. Endometrial explants were prepared from PCOS patients and underwent pharmacological manipulation in vitro. The expression and localization of toll-like receptor 2 (TLR2)/4, key elements of innate immune signal transduction and nuclear factor κB (NFκB) signaling pathways, and multiple cytokines were comprehensively evaluated by Western blotting, immunohistochemistry, and immunofluorescence in endometrial tissues.

RESULTS

We demonstrated the distribution of protein expression and localization associated with the significantly increased androgen receptor, TLR2, and TLR4-mediated activation of interferon regulatory factor-7 (IRF-7) and NFκB signaling, cytokine production, and endometrial inflammation in PCOS patients compared to non-PCOS patients with and without endometrial hyperplasia. In vitro experiments showed that 5-dihydrotestosterone (DHT) enhanced androgen receptor, TLR4, IRF-7, and p-NFκB p65 protein expression along with increased interferon α (IFNα) and IFNɣ abundance. The effects of DHT on IRF-7, p-NFκB p65, and IFN abundance were abolished by flutamide, an antiandrogen. Although 17β-estradiol (E2) decreased p-IRF-7 expression with little effect on TLR-mediated IRF7 and NFκB signaling or on cytokine protein levels, exposure to metformin alone or in combination with E2 suppressed interleukin-1 receptor-associated kinase 4 (IRAK4), p-IRF-7, IRF-7, IκB kinase α (IKKα), p-NFκB p65, IFNɣ, and tumor necrosis factor α protein expression.

CONCLUSION

Cytokine synthesis and increased endometrial inflammation in PCOS patients are coupled to androgen-induced TLR4/IRF-7/NFκB signaling, which is inhibited by metformin treatment.

Campylobacter fetus Induced Proinflammatory Response in Bovine Endometrial Epithelial Cells

Campylobacter fetus subsp. fetus is the causal agent of sporadic abortion in bovines and infertility that produces economic losses in livestock. In many infectious diseases, the immune response has an important role in limiting the invasion and proliferation of bacterial pathogens. Innate immune sensing of microorganisms is mediated by pattern-recognition receptors (PRRs) that identify pathogen-associated molecular patterns (PAMPs) and induces the secretion of several proinflammatory cytokines, like IL-1β, TNF-α, and IL-8. In this study, the expression of IL-1β, TNF-α, IL-8, and IFN-γ in bovine endometrial epithelial cells infected with C. fetus and Salmonella Typhimurium (a bacterial invasion control) was analyzed. The results showed that expression levels of IL-1β and IL-8 were high at the beginning of the infection and decreased throughout the intracellular period. Unlike in this same assay, the expression levels of IFN-γ increased through time and reached the highest peak at 4 hours post infection. In cells infected with S. Typhimurium, the results showed that IL8 expression levels were highly induced by infection but not IFN-γ. In cells infected with S. Typhimurium or C. fetus subsp. fetus, the results showed that TNF-α expression did not show any change during infection. A cytoskeleton inhibition assay was performed to determine if cytokine expression was modified by C. fetus subsp. fetus intracellular invasion. IL-1β and IL-8 expression were downregulated when an intracellular invasion was avoided. The results obtained in this study suggest that bovine endometrial epithelial cells could recognize C. fetus subsp. fetus resulting in early proinflammatory response.

Analysis of miRNA expression changes in bovine endometrial stromal cells treated with lipopolysaccharide

After parturition, bovine uterine stromal cells are often exposed to complex bacterial and viral stimuli owing to epithelial cell rupture, resulting in an inflammatory response. In this study, we used an in vitro model to study the response of bovine endometrial stromal cells to inflammatory mediators and the associated regulated microRNAs in response to lipopolysaccharide. Lipopolysaccharide (LPS) is a bacterial wall component in gram-negative bacteria that causes inflammation upon immune recognition, which is used to create in vitro inflammation models. Thus, we used high-throughput RNA sequencing to identify miRNAs that may have an anti-inflammatory role in the LPS-induced inflammatory response. Two groups of bovine uterine cells were treated with phosphate buffer saline (PBS) and LPS, respectively. Compared with the control (PBS) group, the LPS-treated group had 219 differentially expressed miRNAs, of which 113 were upregulated, and 106 were downregulated. Gene ontology enrichment analysis revealed that the target genes of differentially expressed miRNAs were significantly enriched in several activities, such as transferase activity, small molecule binding, and protein binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the target genes of differential miRNAs were significantly enriched in fluid shear stress and atherosclerosis, MAPK signaling pathway, TNF signaling pathway. By analyzing differentially expressed miRNAs, we found that miR-200c, miR-1247-3p, and let-7b are directly related to the inflammatory response. For instance, miR-200c target genes (MAP3K1, MAP4K3, MAPKAPK5, MAP3K8, MAP3K5) and let-7b target genes (CASP3, IL13, MAPK8, CXCL10) were significantly enriched in the MAPK and IL-17 signaling pathways, respectively. In summary, our research provides insight into the molecular mechanism underlying LPS-induced inflammation in vitro, which may unveil new targets for the treatment of endometritis.

Production of IL-1β, IL-6 and CXCL8 by endometrium of crossbred heifers stimulated with various pathogen-associated molecular patterns

Uterine bacterial infections are common during the post-partum period of dairy herds and, apparently, incidences in crossbred cattle are less than in Holsteins. The aims of this study were (I) to evaluate production of interleukin 1-β (IL-1β), interleukin-6 (IL-6) and chemokine CXCL8 using endometrial explants from Bos indicus crossbred heifers at diestrous, stimulated by various pathogen-associated molecular patterns (PAMP), and (II) assess production of these cytokines by lipopolysaccharide-stimulated endometrial explants from heifers when samples were collected at different stages of estrous cycle. In the first experiment, endometrial explants from heifers at diestrous were stimulated by ten-fold serial dilutions of lipopolysaccharide (LPS), triacylated lipopeptide (PAM3) or peptidoglycan (PGN). In the second experiment, endometrial explants collected at different stages of the estrous cycle were treated with LPS. Concentrations of IL-1β, IL-6 and CXCL8 were quantified in supernatant. There was a marked (P < 0.05) production of IL-1β, IL-6, and CXCL8 in response to LPS treatment. There was also production of IL-1β (P < 0.05) in response to PGN treatment. Explant samples collected at different stages of the estrous cycle responded to LPS treatment with production of IL-1β and IL-6, but with no differences (P > 0.05) between stages of estrous cycle. In conclusion, endometrial samples of crossbred Zebu-based heifers collected during diestrous produced IL-1β, IL-6 and CXCL8 in response to LPS and IL-1β in response to PGN. The cytokine production in response to LPS, however, was not affected by the stage of the estrous cycle in Bos indicus crossbred heifers.

Role of MicroRNAs in Protective Effects of Forsythoside A Against Lipopolysaccharide-Induced Inflammation in Bovine Endometrial Stromal Cells

Bovine endometrial stromal cells (bESCs) are exposed to a complex environment of bacteria and viruses due to the rupture of epithelial cells after delivery. Inflammatory responses are elicited by the activation of host pattern recognition receptors through pathogen-related molecules such as lipopolysaccharides (LPS) on the cell membrane. Forsythoside A (FTA) is a major active constituent of Forsythia suspensa (Thunb.) Vahl. is a flowering plant widely employed as a traditional Chinese herbal medicine to treat various inflammatory diseases such as nephritis, eye swelling, scabies, ulcers, and mastitis; however, the molecular mechanisms underlying its therapeutic effects on bovine endometritis are still unclear. The aim of this study was to explore the role of miRNA and the mechanisms underlying the protective activity of FTA on the inflammation of bovine endometrial stromal cells induced by LPS. Based on previous research, we isolated and cultured bESCs in vitro and categorized them into LPS and LPS+FTA groups with three replicates. Upon reaching 80% confluence, the bESCs were treated with 0.5 μg/mL of LPS or 0.5 μg/mL of LPS + 100 μg/mL of FTA. We, then, performed high-throughput sequencing (RNA-Seq) to investigate the effects of FTA on LPS-stimulated primary bESCs and their underlying mechanisms. We identified 167 miRNAs differentially expressed in the LPS groups; 72 miRNAs were up-regulated, and 95 were down-regulated. Gene ontology enrichment analysis revealed that differentially expressed microRNA (DEGs) were most enriched during the cellular metabolic process; they were mostly located intracellularly and participated in protein, enzyme, and ion binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the DEGs were most enriched in the mitogen-activated protein kinase, tumor necrosis factor, and Interleukin-17 signaling pathways. These results reveal the complex molecular mechanism involved in the FTA and provide a basis for future studies of bovine endometritis treatment with traditional Chinese medicine monomer.

Peptidoglycan Switches Off the TLR2-Mediated Sperm Recognition and Triggers Sperm Localization in the Bovine Endometrium

In mammals, the uterine mucosal immune system simultaneously recognizes and reacts to most bacteria as well as allogenic sperm mainly through the Toll-like receptors (TLR)2/4 signaling pathway. Here, we characterized the impact of pathogen-derived TLR2/4 ligands (peptidoglycan (PGN)/lipopolysaccharide (LPS)) on the immune crosstalk of sperm with the bovine endometrial epithelium. The real-time PCR analysis showed that the presence of low levels of PGN, but not LPS, blocked the sperm-induced inflammatory responses in bovine endometrial epithelial cells (BEECs) in vitro. Immunoblotting analysis revealed that PGN prevented the sperm-induced phosphorylation of JNK in BEECs. Activation or blockade of the TLR2 system in the endometrial epithelium verified that TLR2 signaling acts as a commonly-shared pathway for PGN and sperm recognition. The impairment of endometrial sperm recognition, induced by PGN, subsequently inhibited sperm phagocytosis by polymorphonuclear neutrophils (PMNs). Moreover, using an ex vivo endometrial explant that more closely resembles those in vivo conditions, showed that sperm provoked a mild and reversible endometrial tissue injury and triggered PMN recruitment into uterine glands, while PGN inhibited these events. Of note, PGN markedly increased the sperm attachment to uterine glands, and relatively so in the surface epithelium. However, addition of the anti-CD44 antibody into a PGN-sperm-explant co-culture completely blocked sperm attachment into glands and surface epithelia, indicating that the CD44 adhesion molecule is involved in the PGN-triggered sperm attachment to the endometrial epithelium. Together, these findings demonstrate that, the presence of PGN residues disrupts sperm immune recognition and prevents the physiological inflammation induced by sperm in the endometrial epithelium via the MyD88-dependent pathway of TLR2 signaling, possibly leading to impairment of uterine clearance and subsequent embryo receptivity.

Endometrial extracellular matrix rigidity and IFNτ ensure the establishment of early pregnancy through activation of YAP

Background

In mammals, early pregnancy is a critical vulnerable period during which complications may arise, including pregnancy failure. Establishment of a maternal endometrial acceptance phenotype is a prerequisite for semiheterogeneous embryo implantation, comprising the rate‐limiting step of early pregnancy.

Methods

Confocal fluorescence, immunohistochemistry and western blot for nuclear and cytoplasmic protein were used to examine the activation of yes‐associated protein (YAP) in uterine tissue and primary endometrial cells. The target binding between miR16a and YAP was verified by dual‐luciferase reporter gene assay. The mouse pregnancy model and pseudopregnancy model were used to investigate the role of YAP in the maternal uterus during early pregnancy in vivo.

Results

We showed that YAP translocates into the nucleus in the endometrium of cattle and mice during early pregnancy. Mechanistically, YAP acts as a mediator of ECM rigidity and cell density, which requires the actomyosin cytoskeleton and is partially dependent on the Hippo pathway. Furthermore, we found that the soluble factor IFNτ, which is a ruminant pregnancy recognition factor, also induced activation of YAP by reducing the expression of miR‐16a.

Conclusions

This study revealed that activation of YAP is necessary for early pregnancy in bovines because it induced cell proliferation and established an immunosuppressive local environment that allowed conceptus implantation into the uterine epithelium.

MicroRNAome: Potential and Veritable Immunomolecular Therapeutic and Diagnostic Baseline for Lingering Bovine Endometritis

The bovine endometrium is a natural pathogen invasion barrier of the uterine tissues' endometrial epithelial cells that can resist foreign pathogen invasion by controlling the inflammatory immune response. Some pathogens suppress the innate immune system of the endometrium, leading to prolonged systemic inflammatory response through the blood circulation or cellular degradation resulting in bovine endometritis by bacterial endotoxins. The microRNA (miRNA) typically involves gene expression in multicellular organisms in post-transcription regulation by affecting both the stability and the translation of messenger RNA. Accumulated evidence suggests that miRNAs are important regulators of genes in several cellular processes. They are a class of endogenous non-coding RNAs, which play pivotal roles in the inflammatory response of reproductive diseases. Studies confirmed that miRNAs play a key regulatory role in various inflammatory diseases by mediating the molecular mechanism of inflammatory cytokines via signal pathways. It implicates some miRNAs in the occurrence of bovine endometritis, resorting to regulating the activities of some inflammatory cytokines, chemokine, differentially expressed genes, and protein through modulating of specific cellular signal pathways functions. This review dwells on improving the knowledge of the role of miRNAs involvement in inflammatory response as to early diagnosis, control, and prevention of bovine endometritis and consequently enlighten on the molecular improvement of the genes coded by various differentially expressed miRNA through the need to adopt recent genetic technologies and the development of new pharmaceutical preparations.

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.

Toll-like receptor-mediated innate immunity against herpesviridae infection: a current perspective on viral infection signaling pathways

Background

In the past decades, researchers have demonstrated the critical role of Toll-like receptors (TLRs) in the innate immune system. They recognize viral components and trigger immune signal cascades to subsequently promote the activation of the immune system.

Main body

Herpesviridae family members trigger TLRs to elicit cytokines in the process of infection to activate antiviral innate immune responses in host cells. This review aims to clarify the role of TLRs in the innate immunity defense against herpesviridae, and systematically describes the processes of TLR actions and herpesviridae recognition as well as the signal transduction pathways involved.

Conclusions

Future studies of the interactions between TLRs and herpesviridae infections, especially the subsequent signaling pathways, will not only contribute to the planning of effective antiviral therapies but also provide new molecular targets for the development of antiviral drugs.

Gene expression in bovine endometrial cells and blood-derived neutrophils stimulated by uterine secretions

Uterine epithelial cells (UEC) and migrated polymorphonuclear cells (PMN) play important roles in the uterine defence against microbial infection. The aims of the present study were to investigate i) whether undiluted uterine secretions modulate the expression of genes associated with the innate immune response in UEC and PMN in vitro, ii) whether these changes differ between the two cell populations and iii) whether uterine secretions from cows with subclinical endometritis produce a different response to those from unaffected cows. Therefore, undiluted uterine secretions, cytobrush and biopsy samples were collected from bovine uteri at a local abattoir. All cows had calved at least 3 months prior to sample collection. Subclinical endometritis was diagnosed by cytology (≥5% polymorphonuclear neutrophils) and histology. The uteri were thereby retrospectively categorised as endometritis-positive (E-pos; n = 14), if either the cytology or the histology results were positive, or endometritis-negative (E-neg; n = 17), if both diagnostics were negative. Cultured UEC responded to secretions from E-pos and E-neg cows with an increased gene expression of CXC ligand (CXCL) 8 and interleukin (IL) 6 compared to incubation with control medium alone. PMN expressed significantly higher mRNA levels of CXCL5, CXCL8 and IL1B in response to supernatant from UEC incubated with secretions from both groups (E-pos and E-neg) compared to those incubated with control medium alone. Gene expression of IL10 in uterine epithelial cells remained comparable to the control in cells exposed to E-pos secretions and was 3.6 times lower in those exposed to E-neg secretions. These results demonstrate that the expression of genes associated with the innate immune response in UEC and indirectly also PMN is affected by uterine secretions in vitro. Depending on the target gene, these changes differ between the two cell populations. UEC exposed to uterine secretions from cows without subclinical endometritis produce lower levels of IL10 compared to those exposed to secretions from affected cows or control medium alone. Therefore, the model established in this study can be used as a valuable tool to further understand the contributions of the two cell populations to the coordinated immune response in the uterus.

Peptidoglycan disrupts early embryo-maternal crosstalk via suppression of ISGs expression induced by interferon-tau in the bovine endometrium

Uterine infection with bacteria and the release of peptidoglycan (PGN), antigenic cell wall components of both Gram-negative and Gram-positive bacteria, can cause early pregnancy losses in ruminants, but the associated mechanisms remain unsolved. Day 7 blastocyst starts to secrete a minute amount of interferon-tau (IFNT) in the uterine horn which is required for early stage of maternal recognition of pregnancy (MRP) in ruminants, and it induces interferon stimulated genes (ISGs) for driving uterine receptivity in cows. This study investigated if PGN disrupts IFNT response through modulation of endometrial ISGs expressions. Cultured bovine endometrial epithelial cells (BEECs) were treated with embryo culture medium (ECM) or IFNT (1 ng/ml) in the presence or absence of a low level of PGN (10 pg/ml) for 24 h. A real-time PCR analyses revealed that the presence of PGN suppressed IFNT-induced ISGs (OAS1 and ISG15) and STAT1 expressions in BEECs. To visualize the impact of PGN in an ex-vivo model that resembles the in vivo status, endometrial explants were treated by IFNT (1 ng/ml) with or without PGN (10 pg/ml) for 12 h. PGN suppressed IFNT-induced gene expressions of the above factors, but not for IFNA receptor type1 (IFNAR1) or type2 (IFNAR2) in explants. Immunofluorescence analysis illustrated that PGN completely suppressed the IFNT-triggered OAS1 protein expression in the luminal epithelium of explants. Of note, PGN did not stimulate pro-inflammatory cytokines (TNFA and IL1B) or TLR2 mRNA expression in both models. These findings indicate that the presence of low levels of PGN suppresses ISGs expression induced by IFNT secreted from early embryo, at the luminal epithelium of the bovine endometrium. This could severely interfere with early stage of MRP processes in cows, leading to pregnancy failure.

Persistent effects on bovine granulosa cell transcriptome after resolution of uterine disease

Metritis is associated with reduced fertility in dairy cows, but the mechanisms are unclear because the disease resolves several weeks before insemination. One hypothesis is that metritis causes persistent changes in granulosa cells during follicle development, which might be evident in the transcriptome of granulosa cells from dominant follicles weeks after parturition. To test this hypothesis, we collected the follicular fluid and granulosa cells from dominant follicles 63 days post partum from cows previously diagnosed with metritis, at least 6 weeks after resolution of the disease and from cows not diagnosed with metritis (control cows). Bacterial lipopolysaccharide was detected in follicular fluid, and concentrations were associated with follicular fluid IL-8 and glucose concentrations. Transcriptome analysis using RNAseq revealed 177 differentially expressed genes in granulosa cells collected from cows that had metritis compared with control cows. The most upregulated genes were ITLN1, NCF2, CLRN3, FSIP2 and ANKRD17, and the most downregulated genes were ACSM1, NR4A2, GHITM, CBARP and NR1I3. Pathway analysis indicated that the differentially expressed genes were involved with immune function, cell-cell communication, cell cycle and cellular metabolism. Predicted upstream regulators of the differentially expressed genes included NFκB, IL-21 and lipopolysaccharide, which are associated with infection and immunity. Our data provide evidence for a persistent effect of metritis on the transcriptome of granulosa cells in ovarian follicles after the resolution of disease.

Seminal plasma modulates expression of endometrial inflammatory meditators in the bovine†

Seminal plasma has conventionally been viewed as a transport and survival medium for mammalian sperm; however, its role now extends beyond this process to actively targeting female tissues. Studies in rodents, swine, and humans demonstrate that seminal plasma induces molecular and cellular changes within the endometrium or cervix following insemination. Seminal-plasma-induced alterations to the maternal environment have been theorized to facilitate embryo development, modulate maternal immunity toward the conceptus, and potentially improve pregnancy success. It is unknown if bovine seminal plasma modulates the uterine environment following insemination in the cow, where routine use of artificial insemination reduces maternal exposure to seminal plasma. We hypothesize that seminal plasma modulates the expression of inflammatory mediators in the endometrium, altering the maternal environment of early pregnancy. In vitro, seminal plasma altered intact endometrial explant expression of CSF2, IL1B, IL6, IL17A, TGFB1, IFNE, PTGS2, and AKR1C4. Furthermore, endometrial epithelial cell CSF2, CXCL8, TGFB1, PTGS2, and AKR1C4 expression were increased after seminal plasma exposure, while endometrial stromal cell CSF2, IL1B, IL6, CXCL8, IL17A, TGFB1, PTGS2, and AKR1C4 expression were increased following seminal plasma exposure. Endometrial expression of IL1B was increased in the cow 24 h after uterine infusion of seminal plasma, while other evaluated inflammatory mediators remained unchanged. These data indicate that seminal plasma may induce changes in the bovine endometrium in a temporal manner. Understanding the role of seminal plasma in modulating the maternal environment may aid in improving pregnancy success in cattle.

17β-estradiol regulates prostaglandin E2 and F2α synthesis and function in endometrial explants of cattle

Prostaglandins (PG) have primary functions in the reproductive tract, however, the mechanism of regulation of PG secretion in the endometrium is unclear. Estrogen as a predominant regulator of uterine functions during the mammalian estrous cycle and effects of estrogen on synthesis of PG and function in uterine tissues of cattle are not fully understood. In this study, there was evaluation of the concentration- and time-effects of 17β-estradiol on PG synthesis in endometrial explants of cattle, focusing on the secretion of prostaglandin E₂ (PGE₂) and prostaglandin F_2α (PGF_2α) as well as relative abundance of mRNA transcript and protein for both the enzymes responsible for PGE₂ and PGF_2α synthesis, including prostaglandin-endoperoxide synthase 1 and 2 (PTGS1, PTGS2), PGE₂ synthase (PGES), PGF_2α synthase (PGFS), and carbonyl reductase (CBR1), and the receptors responsible for downstream PGE₂ (PTGER2, PTGER4) and PGF_2α (PTGFR) signaling. Results indicated that 17β-estradiol increased PGE₂ and PGF_2α production at concentrations ranging from 10^-11 to 10^-8 M. Furthermore, abundances of PTGS1, PTGS2, PGES, PGFS, PTGER2, PTGER4, and PTGFR mRNA transcripts and protein were greater immediately after 17β-estradiol treatment at almost all the concentrations, while these CBR1 abundances were less as a result of treatments with 17β-estradiol. These data support the hypothesis that estradiol modulates the synthesis and function of PG in the endometrium of cattle.

Glutamine supports the protection of tissue cells against the damage caused by cholesterol-dependent cytolysins from pathogenic bacteria

Pathogenic bacteria often damage tissues by secreting toxins that form pores in cell membranes, and the most common pore-forming toxins are cholesterol-dependent cytolysins. During bacterial infections, glutamine becomes a conditionally essential amino acid, and glutamine is an important nutrient for immune cells. However, the role of glutamine in protecting tissue cells against pore-forming toxins is unclear. Here we tested the hypothesis that glutamine supports the protection of tissue cells against the damage caused by cholesterol-dependent cytolysins. Stromal and epithelial cells were sensitive to damage by the cholesterol-dependent cytolysins, pyolysin and streptolysin O, as determined by leakage of potassium and lactate dehydrogenase from cells, and reduced cell viability. However, glutamine deprivation increased the leakage of lactate dehydrogenase and reduced the viability of cells challenged with cholesterol-dependent cytolysins. Without glutamine, stromal cells challenged with pyolysin leaked lactate dehydrogenase (control vs. pyolysin, 2.6 ± 0.6 vs. 34.4 ± 4.5 AU, n = 12), which was more than three-fold the leakage from cells supplied with 2 mM glutamine (control vs. pyolysin, 2.2 ± 0.3 vs. 9.4 ± 1.0 AU). Glutamine cytoprotection did not depend on glutaminolysis, replenishing the Krebs cycle via succinate, changes in cellular cholesterol, or regulators of cell metabolism (AMPK and mTOR). In conclusion, although the mechanism remains elusive, we found that glutamine supports the protection of tissue cells against the damage caused by cholesterol-dependent cytolysins from pathogenic bacteria.

Adaptive immunity in the postpartum uterus: Potential use of vaccines to control metritis

After parturition, dairy cows rely on an effective innate immune response, through the actions of neutrophils, macrophages, and antimicrobial peptides, to clear the uterus from pathogenic bacteria, such as E. coli, Bacteroides spp, F. necrophorum and T. pyogenes. However, the role of adaptive immunity in the postpartum uterus is less understood. In this review, we explore concepts of mucosal adaptive immunity and discuss recent findings regarding the efficacy of vaccines to reduce metritis in dairy cows. Areas of lymphocytic aggregates are seen throughout the bovine reproductive tract after parturition, but it is unknown if their development is influenced by previous exposure to pathogens or other intrinsic factors. Through the actions of Treg cells and γδ T cells, the uterus is an immune-tolerant environment during pregnancy. After parturition, the dynamics in the endometrial and circulating lymphocytic populations differ among cows that develop uterine diseases and healthy counterparts. However, the functionality of those cells has not yet been determined. It has been hypothesized that cows that fail to switch their uterine environment from an anti-inflammatory state prior to parturition to a pro-inflammatory state after calving are more susceptible to uterine infections. Given the nature of metritis related pathogens and the importance of innate immunity to uterine defense mechanisms, we speculate that an adaptive immunity biased towards a Th1/Th17 cellular response will provide best protection against uterine infections. Few studies have evaluated the efficacy of immunization in reducing the incidence of metritis in dairy cows revealing inconsistent findings.