IFN-τ Attenuates LPS-Induced Endometritis by Restraining HMGB1/NF-κB Activation in bEECs

Cis-eQTL analysis reveals genes involved in biological processes of the immune system in Nelore cattle

The combination of transcriptional profiling and genotype data analyses enables the identification of genetic variants that may affect gene expression (eQTL - expression quantitative trait loci). This study aimed to identify cis-eQTL in Nellore cattle muscle tissue and determine their biological processes related to the immune system and involved eGenes. Genotypic data (SNP-Chip) and gene expression data (RNA-Seq) from a commercial population of 80 Nellore animals were evaluated. For the cis-eQTL identification, association tests were conducted for all variants near the gene (cis variants), followed by permutation tests to correct for multiple comparisons. Our analyses revealed 828 top cis-eQTL related to 1,062 genes of which most of these variants were in intronic and intergenic regions. The eQTLs rs109525554, rs109589165, rs110192253, rs133127698, rs137742430, rs41803313, rs43366333, and rs43711242 were associated with susceptibility and resistance to infections in cattle. Additionally, interferon family eGenes, such as IFNT3, IFN-TAU, IFNK, FYN, and IFNW1, and endothelial leukocyte migration, such as PRKCG and CXCL10 were found. These eGene families were linked to biological processes of innate and adaptive immune responses and associated with somatic cell scores in cattle, respectively. Our results may have implications for selecting desirable resistance traits in animals bred for production and highlight the importance of studying genetic variants involved in quantitative traits to improve our understanding of genetic mechanisms underlying gene expression regulation of adaptive traits in cattle.

Beclin1 regulates yak endometrial inflammation and TLR4/NF-κB signaling pathway through autophagy/non-autophagy function

Beclin1 is an autophagy related factor, and it is capable of mediating non-autophagy functions, too. Yak endometritis represents a significant obstetric ailment that impedes the normal breeding process. The current understanding of the beclin1 effect on endometrial inflammation in yak remains limited. Accordingly, this study initially examined the expression profile of beclin1 in yak endometritis in vitro and vivo. Subsequently, the beclin1 was targeted inhibit through small interfering RNA (siRNA), with the objective of elucidating the regulatory function of beclin1 in yak endometritis. The findings reveal that expression of beclin1 in inflammatory tissues of yak endometrium is markedly elevate in comparison to control group, and predominant localization in the cytoplasm of the endometrium and uterine glands. 1 µg/mL Lipopolysaccharide (LPS) was demonstrated to induce yak endometrial epithelial cells (YEECs) inflammation and increase the expression of beclin1. YEECs are disposed with 1 μg/mL LPS, resulting in a gradual increase of p62 expression from 0 h to 6 h, and significant decrease at 12 h, at 9 h to 12 h the expression of LC3 significant increase. These findings indicate that LPS impairs autophagy during the initial stages of inflammation, complete autophagy is occurred in cells during the subsequent phase. Initial stages of inflammation, inhibit beclin1 result significantly reduced expression of inflammatory factors (TNF-α and IL-1β) and TLR4/NF-κB signaling pathway (p65, IκBα phosphorylation, p65 nuclear translocation) compared to the control group. When complete autophagy occurred, inhibit beclin1 inhibit autophagy, result in a significantly higher expression of inflammatory factors (TNF-α and IL-1β) and TLR4/NF-κB signaling pathway than the control group. In conclusion, this study demonstrates for the beclin1 exerts both autophagic and non-autophagic functions during the inflammatory process in YEECs, making it become a potential target for the cure and diagnosis of various yak endometritis.

IFN-τ Maintains Immune Tolerance by Promoting M2 Macrophage Polarization via Modulation of Bta-miR-30b-5p in Early Uterine Pregnancy in Dairy Cows

Pregnancy failure in the first trimester of cows significantly impacts the efficiency of the dairy industry. As a type I interferon exclusively to ruminants, IFN-τ plays a key role in maternal recognition and immune tolerance of fetuses. Macrophages are the most common immune cells within the ruminant endometrium. Nevertheless, deeply analyzing the mechanisms of IFN-τ regulating macrophage polarization still needs further study. In this study, a notable decline of bta-miR-30b-5p expression via the increase of SOCS1 was observed in uterine tissues of pregnant cows. We then confirmed that the 3'UTR of SOCS1 was to be directly targeted by bta-miR-30b-5p. After that, we demonstrated that this obviously promoted the bovine macrophages (BoMac) polarized to M2 through enhancing SOCS1 expression with the treatment of IFN-τ. Furthermore, we found that SOCS1 restrained the expression of the key proteins p65 and p-P65 in the NF-κB pathway. Causing, the wide range of cross-species activities of IFN-τ, therefore we established a pregnant mouse model for the future confirmation of the above mechanism. The results verified that IFN-τ significantly improved this mechanism and maintained normal pregnancy status in mice, but miR-30b-5p significantly reduced the M2 polarization by inhibiting SOCS1, which activated the NF-κB signaling pathway, and then leading to the failure of embryo implantation. All these results indicated that IFN-τ can regulate immune tolerance during pregnancy by promoting M2 macrophage polarization through inhibiting bta-miR-30b-5p targeting SOCS1 to deactivate the NF-κB signaling pathway.

Response of bovine endometrium to interferon tau in the presence of lipopolysaccharide

We recently demonstrated that conceptus-derived interferon tau (IFNT), responsible for maternal recognition in cattle, acts on the uterus in a dose- and time-dependent manner by upregulating key interferon-stimulated genes (ISGs) in the endometrium. In high producing dairy cows, postpartum uterine infection is a major factor influencing fertility and pregnancy outcome. Lipopolysaccharide (LPS), an endotoxin of Gram-negative bacteria such as Escherichia coli, generates an altered uterine environment by inducing excessive inflammation at the maternal-conceptus interface. Thus, we aimed to investigate whether the endometrial response to IFNT is altered in the presence of LPS. Endometrial explants were isolated from uteri collected at a local abattoir from Holstein Friesian cows (n = 8) during the mid-luteal stage of the estrous cycle, and cultured in RPMI medium for 24 h in 5 % CO2 in humidified air without (control), or with IFNT (100 ng/mL), a single Day 15 conceptus, LPS (1 μg/mL), both IFNT and LPS, or both a Day 15 conceptus and LPS. Incubation with IFNT and a Day 15 conceptus up-regulated (P < 0.05) well-known classical ISGs (ISG15, OAS1, MX1 and MX2) as well as other candidate ISGs (CMPK2, IFI35, TRIM38 and TNFSF10) and down-regulated expression of IL1B in endometrial explants. Incubation with LPS increased (P < 0.05) abundance of NFKB1 (a key transcription factor involved in inflammatory and immune response), TNFA, IL1B and IL6 (pro-inflammatory cytokines), IL10 (anti-inflammatory cytokine), IL8, CXCL1, CXCL3 and CCL2 (chemokines), and, to a lesser extent, classical ISGs in endometrial explants. However, LPS did not alter endometrial response to IFNT, irrespective of IFNT concentration (1, 10 or 100 ng/mL). Results suggest that the expression of ISGs, up-regulated by conceptus-derived IFNT, is not altered in the endometrium in the presence of LPS; however, the increased expression of inflammation-related genes induced by LPS indicate an altered endometrial immune response that may be associated with compromised pregnancy establishment or pregnancy failure.

A20 Alleviates the Inflammatory Response in Bovine Endometrial Epithelial Cells by Promoting Autophagy

Endometritis represents a prevalent condition in perinatal dairy cows. Bovine endometrial epithelial cells (BEECs), as the primary interface between cavity and the external environment, are particularly vulnerable to infection by pathogenic bacteria following parturition. A20 is essential for regulating inflammation and modulating immune responses. Nevertheless, the exact role of A20 in the BEECs in response to inflammatory response is not fully understood. An endometritis model infected by Escherichia coli (E. coli) in vivo and a BEECs inflammation model induced with lipopolysaccharide (LPS) in vitro were built to investigate the function and governing mechanisms of A20 in endometritis. The results showed that infection with E. coli resulted in endometrial damage, inflammatory cell infiltration, and upregulation of inflammatory factors in dairy cows. Furthermore, A20 expression was upregulated in the endometrium of cows with endometritis and in BEECs following LPS stimulation. A20 overexpression attenuated the level of proinflammatory cytokines in LPS-stimulated BEECs; conversely, A20 knockdown lead to an exacerbated response to LPS stimulation. The overexpression of A20 was shown to activate autophagy and suppress the NF-κB signaling pathway in LPS-stimulated BEECs. However, blocking autophagy with chloroquine notably attenuated the anti-inflammatory effect of A20, leading to the activation of the NF-κB signaling pathway. In summary, the study demonstrated that A20's suppression of inflammation in LPS-stimulated BEECs is associated with the activation of autophagy. Therefore, the A20 protein showed potential as a novel treatment focus for managing endometritis in dairy cows.

An Overview of Bioactive Compounds' Role in Modulating the Nrf2/Keap1/NF-κB Pathway to Alleviate Lipopolysaccharide-Induced Endometritis

Endometritis is a common inflammatory condition of the uterine endometrial lining that primarily affects perinatal dairy animals and causes significant economic losses in agriculture. It is usually triggered by pathogenic bacteria and is associated with chronic postpartum reproductive tract infections. Bacterial lipopolysaccharides (LPSs) are known to increase levels of reactive oxygen species (ROS), leading to oxidative stress and inflammation through the activation of the NF-κB signaling pathway and the inhibition of Nrf2 nuclear translocation, which regulates antioxidant response elements (AREs). The effectiveness of the conventional management strategy involving antibiotics is decreasing due to resistance and residual concerns. This review explores the potential therapeutic benefits of targeting the Nrf2/Kelch-like ECH-associated protein 1 (Keap1)/NF-κB signaling pathway to alleviate LPS-induced endometritis. We discuss recent advancements in veterinary medicine that utilize exogenous antioxidants to modulate these pathways, thereby reducing oxidative stress and inflammatory responses in endometrial cells. This review highlights the efficacy of several bioactive compounds that enhance Nrf2 signaling and suppress NF-κB activation, offering protective effects against oxidative damage and inflammation. By examining various in vitro studies, this review emphasizes the emerging role of these signaling pathways in developing new therapeutic strategies that could potentially replace or supplement traditional treatments and mitigate the economic impacts of endometritis in livestock.

RNA Sequencing Reveals the Involvement of Serum Exosomal miRNAs in Early Pregnancy in Cattle

Low fertility is the main cause of the low productivity in beef cattle and is mainly associated with a lack of conception after fertilization. The establishment of early pregnancy in cattle is a complex physiological process, and embryo implantation is crucial for the successful establishment of pregnancy. Exosomal miRNAs play an important role in regulating mammalian embryo implantation and development. This study used synchronous estrus technology to extract exosomes from bovine serum at 0, 14, and 21 days of early pregnancy and analyzed the expression profile of exosomal miRNAs through RNA-seq technology. We identified 472 miRNA precursor sequences and 367 mature miRNA sequences in the three sample groups, with the majority of the miRNAs having high abundance. Differentially expressed miRNAs (DEmiRNAs) were screened, and 20 DEmiRNAs were obtained. The differential expression analysis results show that compared to day 0, there were 15 DEmiRNAs in the serum on day 14 and 5 on day 21 of pregnancy. Compared to the 14th day of pregnancy, there were eight DEmiRNAs in the serum on the 21st day of pregnancy. Bioinformatics analysis shows that the target genes of DEmiRNAs regulated the signaling pathways closely related to early pregnancy, including the VEGF, NF-κB, and MAPK signaling pathways. In addition, the newly discovered miRNAs were bta-miR-3604, bta-miR-2889, bta-miR-3432a, and bta-miR-409b. These results provide a theoretical reference for screening the molecular markers for early pregnancy establishment and maternal recognition of pregnancy (MRP) in cattle and new ideas for shortening the calving interval in cows.

Targeting inflammation for the treatment of endometritis in bovines

The uterine endometrial surface of bovines is in constant exposureconstantly exposed with to a multitude ofmany microbial populations that changes throughout the post-partum phase in terms of complexity and dynamics. These microbes contribute to the host pathology, leading to severe economic losses along withnd reproductive capabilities. The basic primary interface that occurs between the internal tissues of the body of the hostbetween the host body's internal tissues and the microbes is the endometrial surface of the uterus. As a result of the infinite pathogenic population, there is always a danger for the opportunistic organisms to attack. Therefore, it is paramount that any interactions, especially microbial microbes with the endometrial surface, are regulated by the host cells. However, the inflammatory response as the defense mechanism contributes a pivotal roleis pivotal in host immunity and pathology. The inflammatory cascade and pathways are important essential to eliminate this clinical problem. In this review, we will discuss and explain how the inflammation and the various components of the immune system play their role in host pathology and therapeutic strategies, taking into account the interface between the host and the microbes on the surface of the endometrium. This review is also instrumental in further explanation of inflammatory uterine disease by discussing the response of inflammation to external insult.

Autophagy activation alleviates the LPS-induced inflammatory response in endometrial epithelial cells in dairy cows

PROBLEM

Endometritis is a common disease that affects dairy cow reproduction. Autophagy plays a vital role in cellular homeostasis and modulates inflammation by regulating interactions with innate immune signaling pathways. However, little is known about the regulatory relationship between autophagy and inflammation in bovine endometrial epithelial cells (BEECs). Thus, we aimed to determine the role of autophagy in the inflammatory response in BEECs.

METHODS OF STUDY

In the present study, the expression levels of proinflammatory cytokines were measured by quantitative real-time polymerase chain reaction. Changes in the nuclear factor-κB (NF-κB) pathway and autophagy were determined using immunoblotting and immunocytochemistry. The induction of autophagosome formation was visualized by transmission electron microscopy.

RESULTS

Our results demonstrated that autophagy activation was inhibited in LPS-treated BEECs, while activation of the NF-κB pathway and the mRNA expression of IL-6, IL-8, and TNF-α were increased. Furthermore, blocking autophagy with the inhibitor chloroquine increased NF-κB signaling pathway activation and proinflammatory factor expression in LPS-treated BEECs. Conversely, activation of autophagy with the agonist rapamycin inhibited the NF-κB signaling pathway and downregulated proinflammatory factors.

CONCLUSIONS

These data indicated that LPS-induced inflammation was related to the inhibition of autophagy in BEECs. Thus, the activation of autophagy may represent a novel therapeutic strategy for eliminating inflammation in BEECs.

MiR-495-3p attenuates cell pyroptosis and endometritis through inhibiting the activation of NLRP3 inflammasome in bovine

miR-495 is aberrantly expressed and affects the progression of inflammation in various diseases. However, the mechanisms of miR-495 in bovine endometritis remain largely unknown. This study investigated the mechanism of miR-495 in lipopolysaccharide (LPS)-induced bovine endometritis and pyroptosis and found that miR-495 inhibits NLRP3 inflammasome activation and inflammatory immune responses in endometritis tissue and cell models. Bovine endometrial epithelial cells (BENDs) were treated with 10 μg/mL LPS to establish a cell inflammatory model. LPS stimulation activated the NLRP3 inflammasome and elevated the expression of proinflammatory factors in BEND cells. In addition, pyroptosis and methylation-dependent inhibition of miR-495 was discovered in LPS-exposed BENDs. Furthermore, overexpression of miR-495 inhibited activation of the NLRP3 inflammasome in vitro and vivo. Collectively, our data demonstrate that miR-495 can attenuate activation of the NLRP3 inflammasome to protect against pyroptosis and bovine endometritis, which provides novel therapeutic targets for bovine endometritis and other inflammatory diseases.

TNFAIP3 interacting protein 2 relieves lipopolysaccharide (LPS)-induced inflammatory injury in endometritis by inhibiting NF-kappaB activation

BACKGROUND

Endometritis seriously affects the health of women, and it is important to identify new targets for its treatment.

OBJECTIVE

This study aimed to explore the role of TNFAIP3 interacting protein 2 (TNIP2) in endometritis through human endometrial epithelial cells (hEECs) stimulated by lipopolysaccharide (LPS).

METHODS

hEECs were induced with LPS to build a cellular model of endometritis. Cell growth and apoptosis were detected by cell counting kit-8 and flow cytometry. The TNIP2 mRNA and protein levels were measured using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. The caspase3 activity was calculated using a Caspase3 activity kit. Interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) levels were determined by enzyme-linked-immunosorbent-assay. The reactive oxygen species (ROS), lactate dehydrogenase (LDH), catalase (CAT), and superoxide dismutase (SOD) levels were determined using the corresponding kits. Nuclear factor-kappaB (NF-κB) pathway was determined by western blot assay.

RESULTS

TNIP2 was downregulated in the LPS-induced endometritis cell model. Cell viability was reduced, apoptosis was enhanced, and IL-6, IL-1β, and TNF-α levels increased in LPS-induced hEECs. Additionally, LDH activity and ROS concentration were upregulated, whereas CAT and SOD activities were downregulated in LPS-induced hEECs. These results were reversed by TNIP2 overexpression. Moreover, the results hinted that NF-κB was involved in the effects of TNIP2 on the LPS-induced endometritis cell model.

CONCLUSION

TNIP2 alleviated endometritis by inhibiting the NF-κB pathway, suggesting a potential therapeutic target for endometritis.

Protective effect of the total flavonoids from Clinopodium chinense against LPS-induced mice endometritis by inhibiting NLRP3 inflammasome-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Clinopodium chinense (Benth.) O. Kuntze (C. chinense) is a Chinese herbal medicine used in treating gynecological hemorrhagic diseases for hundreds of years. Flavonoids are one kind of the major components in C. chinense. The flavonoids of C. chinense (TFC) have a vital role in treating endometritis but the underlying therapeutic mechanisms of TFC against endometritis have been rarely reported.

AIM OF THE STUDY

To elucidate the therapeutic effect and possible mechanisms of TFC against lipopolysaccharide (LPS)-induced endometritis in vivo and LPS-induced primary mouse endometrial epithelial cells (MEECs) injury in vitro.

MATERIALS AND METHODS

The holistic phytochemicals of the TFC and TFC-contained serum were screened and identified using UPLC-Q-TOF-MS. The model of endometritis was established by intrauterine injection of LPS (5 mg/mL) into female BALB/c mice, and the model mice were treated with TFC for 7 days. The value of MPO was measured by Myeloperoxidase assay kit, the pathological changes in the endometrium were evaluated using H&E staining and transmission electron microscope (TEM), the secretions of IL-18, IL-1β and TNF-α were determined by ELISA kits, the mRNA expressions of IL-18, IL-1β and TNF-α were determined by RT-PCR assay, and the protein levels of TLR4, IKBα, p-IKBα, p65, p-p65, caspase-1, ASC, NLRP3 and GSDMD were measured by Western blot. Subsequently, MEECs were isolated from the uterus of pregnant female mice, injured by LPS for 24 h and incubated with the TFC-contained serum. Finally, cell viability, LDH release, hoechst 33342/PI staining, immunofluorescence staining, scanning electron microscope observation, ELISA assay, RT-PCR detection and Western blot analysis were carried out to further validate the therapeutic effect and the underlying mechanisms of TFC.

RESULTS

A total of 6 compounds in the plasma of mice after being intragastric administrated of TFC were identified. The results in vivo showed that TFC significantly reduced MPO value and alleviated pathological injury of the endometrium. Furthermore, TFC significantly decreased the serum IL-18, IL-1β and TNF-α levels, and the mRNA levels of IL-18, IL-1β and TNF-α. TFC also inhibited the expressions of TLR4, p-IKBα, p-p65, caspase-1, ASC, NLRP3 and GSDMD. Besides, compared with the model group in MEECs cells, TFC-contained serum prevented pyroptosis, decreased the levels of IL-18 and IL-1β, and inhibited the mRNA expressions of IL-18, IL-1β and GSDMD. TFC-contained serum also reversed the activation of NLRP3 inflammasome caused by nigericin, and restrainted the translocation of NF-κB into nuclear.

CONCLUSIONS

TFC protects mice endometritis from the injury of LPS via suppressing the activation of NLRP3 inflammasome and pyroptosis, the underlying mechanisms of which were related to restraining the TLR4/NF-κB/NLRP3 pathway activation.

Citral protects against LPS-induced endometritis by inhibiting ferroptosis through activating Nrf2 signaling pathway

INTRODUCTION

Endometritis is the inflammatory condition of the uterus. Citral, a component of lemongrass oil, is known to exhibit anti-inflammatory activity.

AIM

The effects of citral on LPS-induced endometritis were tested and the mechanisms were investigated.

METHODS

LPS-induced endometritis mice model was established and the effects of citral were detected using this model. Inflammatory cytokines were tested by ELISA. Ferroptosis was assessed by detecting GSH, ATP, MDA, and Fe2+ levels. Signaling pathway was tested by western blot analysis.

RESULTS

Citral prevented LPS-induced endometritis through attenuating uterine pathological changes and inflammatory cytokine release. Meanwhile, citral prevents LPS-induced ferroptosis through attenuating MDA and Fe2+ levels, as well as increasing ATP and GSH levels. Furthermore, citral up-regulated Nrf2 and HO-1 expression and attenuated NF-κB activation. In addition, in Nrf2 knockdown mice, the inhibitory roles of citral on ferroptosis and endometritis were largely reversed.

CONCLUSION

Taken together, citral inhibited LPS-induced endometritis through preventing ferroptosis, which were regulated by Nrf2 signaling pathway.

Enhanced expression of miR-26a ameliorates lipopolysaccharide-induced endometritis by targeting MAP3K8 to inactivate MAPK signaling pathway

Endometritis is a severe postpartum inflammatory disease that puts cows' reproductive health at risk and causes the dairy industry to suffer significant financial losses. The present study aimed to investigate the regulatory role of miR‑26a in LPS‑induced bovine endometrial epithelial cells (bEECs) and the implication for endometritis. Here, we found inflammatory cell infiltration and destruction of endometrial structure in cow uterus, and dramatic increase in myeloperoxidase (MPO) activity and upregulation of pro-inflammatory cytokines (IL-1β, TNF-α, and IL-6) in endometritis. Meanwhile, miR-26a was down-regulated, but MAP3K8 was increased in the uterine tissue of endometritis. Similarly, the expression of miR-26a was significantly decreased in LPS-stimulated bEECs, while MAP3K8 was risen. In addition, we further verified that MAP3K8 was a target of miR-26a by dual-luciferase reporter assay. Under LPS stress, over-expressing miR-26a markedly decreased MAP3K8 expression levels, along with the reduced expression of inflammatory factors, such as IL-1β, TNF-α and IL-6, whereas this effect was countered by the inhibition of miR-26a. Furthermore, we demonstrated that miR-26a overexpression prevented the MAPK pathway from being activated by targeting MAP3K8. Then we carried out experiments in LPS-stimulated mice uterus to expound that MAP3K8 was essential in endometritis development, which further confirmed the reliability of the above results. In conclusion, overexpression of miR-26a effectively inhibited the expression of MAP3K8 in LPS-induced bEECs and thereby partially suppressed the activation of MAPK signaling pathway. miR-26a and MAP3K8 may be a promising biomarker and therapeutic target for dairy cow endometritis.

Epigallocatechin-3-gallate (EGCG) attenuates inflammatory responses and oxidative stress in lipopolysaccharide (LPS)-induced endometritis via silent information regulator transcript-1 (SIRT1)/nucleotide oligomerization domain (NOD)-like receptor pyrin domain-containing 3 (NLRP3) pathway

The protective effects of epigallocatechin-3-gallate (EGCG) on lipopolysaccharide (LPS)-induced endometritis in vivo and in vitro will be explored in this study. The endometritis model was induced in female BALB/c mice uterus by perfusion with lipopolysaccharide (LPS) and EGCG were administered at 1 h before LPS induction. The primary bovine endometrial epithelial cells (BEECs) were treated with EGCG for 1 h before LPS stimulation. Uterine histopathological changes, myeloperoxidase (MPO) activity, inflammatory cytokine levels and oxidative stress markers were determined. The extent of Bax, Bcl-2, cleaved caspase-3, silent information regulator transcript-1 (SIRT1), nucleotide oligomerization domain (NOD)-like receptor pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC) and Caspase1 was detected by Western blot and real-time quantitative PCR assays. The results showed that EGCG significantly reversed the LPS-induced uterine histopathological changes, MPO activity, pro-inflammatory cytokine levels. Additionally, EGCG decreased oxidative stress and reduced cell apoptosis by upregulating SIRT1 expression, downregulating the NLRP3 inflammasome activation. These findings indicated that EGCG exerted its greatest protective effects by blocking inflammatory responses, lowering oxidative stress, and reducing apoptosis via the SIRT1/NLRP3, making its promising candidate treatment for endometritis.

Baicalin alleviates endometrial inflammatory injury through regulation of tight junction proteins

Endometritis is the foremost reason for reduced reproductive performance, which impedes the establishment of pregnancy in ruminants. Baicalin is extensively acknowledged as a tocolytic drug. However, the preventive effect of baicalin on endometrial inflammatory injury remains unclear. The present study aimed to determine the potential benefits of baicalin on endometrial inflammatory injury in animal and cellular models. The results showed that baicalin alleviated the impairment of tight junctions (TJs) and inflammation in the endometrium induced by LPS treatment. Baicalin increased claudin 3 (CLDN3) and tight junction protein 1 (TJP1) levels in a dose-dependent manner in endometrial epithelial cells (EECs) accompanied by autophagy activation with or without LPS treatment. Immunofluorescence staining revealed that baicalin pretreatment prompted MAP1LC3B-positive structures to surround TJ proteins in the cytoplasm and decreased the abnormal aggregation of CLDN3 and TJP1 in the cytosol of EECs. Activation or blockage of autophagy using pharmacologic methods affected the redistribution of TJ proteins by baicalin pretreatment with LPS treatment. The role of autophagy in the modulation of TJ proteins was also confirmed by ATG7 and TFEB overexpression, as evidenced by accelerated redistribution of CLDN3 and TJP1 from the EEC cytosol to the membrane and a loss of membranous CLDN2 in EECs. These data demonstrate that baicalin influences the redistribution of TJ proteins to maintain the barrier function during LPS-induced endometrial inflammatory injury by regulating autophagy and provides a new therapeutic to potentially prevent embryo loss and endometritis.

IFN-τ mediated miR-26a targeting PTEN to activate PI3K/AKT signalling to alleviate the inflammatory damage of bEECs

Endometritis is the failure of embryo implantation and an important cause of infertility in dairy cows. IFN-τ is a type I interferon unique to ruminants. In regulating the process of inflammatory response, IFN-τ can be expressed through MicroRNAs (miRNAs) to regulate the process of inflammation. However, IFN-τ regulates lipopolysaccharide (LPS)-induced inflammatory injury of bEECs through the highly conserved miR-26a in mammals, and the mechanism remains unclear. Bovine endometrial epithelial cells (bEECs)were isolated and cultured to establish an inflammatory injury model. RT–qPCR and ELISA were used to detect the secretion of inflammatory factors. Dual-luciferase assays and target gene silencing assays determine the regulatory role of miRNAs. The target protein was detected by immunofluorescence and western blotting. This study showed that the expression of miR-26a was significantly down-regulated in mouse endometrium inflammatory injury tissue and LPS stimulated bEECs; and IFN-τ reversed the expression of miR-26a. The study also showed that the overexpression of miR-26a significantly inhibited the secretion of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α. In addition, studies have shown that miR-26a inhibits its translation by targeting PTEN 3′-UTR, which in turn activates the Phosphatidylinositide 3-kinases/protein kinase B (PI3K/AKT) pathway, so that nuclear factor kappa-B (NF-κB) signaling is inhibited. In summary, the results of this study further confirm that IFN-τ as an anti-inflammatory agent can up-regulate the expression of miR-26a and target the PTEN gene to inhibit the inflammatory damage of bEECs.

Two New Xanthones from the Twigs of Calophyllum membranaceum and Their Anti-Inflammatory Activities in HESC Cells

Two new xanthones, calmemxanthone A (1) and calmemxanthone B (2), along with eleven known compounds were isolated from the dried twigs of Calophyllum membranaceum Gardn. et Champ. The structures of compounds 1 and 2 were established by analysis of spectra and mass spectrometry data. The absolute configuration of compound 1 was confirmed by electronic circular dichroism (ECD) spectral analysis. The anti-inflammation action of these compounds were evaluated on lipopolysaccharide (LPS)-induced inflammatory damage to human endometrial stromal cells (HESCs), and the structure-activities of 1-13 were also discussed. Compound 10 presented the anti-inflammation action with an IC₅₀ value of 20.3 μM, that might be relevant to the regulation of NF-κB signaling pathway via the suppression of TRIF, IKKα, and IκBα.

Inhibition of Neutrophil Extracellular Traps Formation by Cl-Amidine Alleviates Lipopolysaccharide-Induced Endometritis and Uterine Tissue Damage

Endometritis is a common disease that affects the production in dairy cows and leads to severe losses in the dairy industry. Neutrophil extracellular traps (NETs) formation promotes pathogenic invasions of the lumen of the tissue, leading to inflammatory diseases such as mastitis, pancreatitis, and septic infection. However, research that could show the relationship between NETs and endometritis is scarce. Cl-amidine has been shown to ameliorate the disease squealing and clinical manifestation in various disease models. In this study, we investigated the role of NETs in LPS-triggered endometritis in rats and evaluated the therapeutic efficiency of Cl-amidine. An LPS-induced endometritis model in rats was established and found that the formation of NETs can be detected in the rat's uterine tissues in vivo. In addition, Cl-amidine treatment can inhibit NETs construction in LPS-induced endometritis in rats. Myeloperoxidase (MPO) activity assay indicated that Cl-amidine treatment remarkably alleviated the inflammatory cell infiltrations and attenuated the damage to the uterine tissue. The Western blot results indicated that Cl-amidine decreased the expression of citrullinated Histone H3 (Cit-H3) and high-mobility group box 1 protein (HMGB1) protein in LPS-induced rat endometritis. The ELISA test indicated that Cl-amidine treatment significantly inhibited the expression of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. The NETs were determined by Quant-iTTMPicoGreen dsDNA kit®, which indicated that Cl-amidine significantly inhibited the NETs in rat serum. All results showed that Cl-amidine effectively reduced the expression of Cit-H3 and HMGB1 proteins by inhibiting the formation of NETs, thereby attenuating the inflammatory response to LPS-induced endometritis in rats. Hence, Cl-amidine could be a potential candidate for the treatment of endometritis.

ISGylation Inhibits an LPS-Induced Inflammatory Response via the TLR4/NF-κB Signaling Pathway in Goat Endometrial Epithelial Cells

Simple Summary

Endometritis is a common and important reproductive disease of domestic animals, leading to repeated infertility, abortion, and ovarian dysfunction, which affects the reproductive rate and production performance of female domestic animals, and causes serious financial loss to farmers. Infection with Gram-negative bacteria, the release of LPS and activation of the TLR4/NF-κB signaling pathway are the principal factors responsible for the disease. However, the mechanism of the interaction between endometrial immunity and bacterial infection is not entirely clear. Ubiquitin-like protein ISG15 can regulate the TLR4/NF-κB signaling pathway via the ISGylation modification system, which modulates the inflammatory response. In the present study, we found that ISG15 proteins were mainly located in the cytoplasm of goat endometrial epithelial cells (gEECs) and that the expression of key genes and proteins of ISGylation increased in LPS-induce gEECs. Overexpression and silencing of the ISG15 gene demonstrated that ISGylation inhibited an LPS-induced inflammatory response via the TLR4/NF-κB signaling pathway in gEECs. Here, we provide the experimental basis for further exploration of the role of the ISGylation modification system in the inflammatory response of endometrium and a potential method for the treatment of endometritis.

Abstract

Endometritis is a common and important reproductive disease of domestic animals. The principal factors responsible for the disease are infection with Gram-negative bacteria, the release of Lipopolysaccharides (LPS) and activation of the TLR4/NF-κB signaling pathway. However, we do not fully understand the interaction between endometrial immunity and bacterial infection in the disease etiology. The ubiquitin-like protein ISG15 can regulate the TLR4/NF-κB signaling pathway via the ISGylation modification system, modulating the inflammatory response. In the present study, we found that ISG15 protein was expressed mainly in the cytoplasm of goat endometrial epithelial cells (gEECs) and that the expression of key genes and proteins of ISGylation increased in LPS-induced gEECs. Overexpression and silencing of the ISG15 gene demonstrated that ISGylation inhibited an LPS-induced inflammatory response via the TLR4/NF-κB signaling pathway in gEECs. Here, we provide the experimental basis for further exploration of the role of the ISGylation modification system in the inflammatory response of endometrium and a potential method for the treatment of endometritis.