Cortisol inhibits the Escherichia coli-induced endometrial inflammatory response through NF-κB and MAPK pathways in postpartum goats

Selenium elicited an enhanced anti-inflammatory effect in primary bovine endometrial stromal cells with high cortisol background

BACKGROUND

An elevated endogenous cortisol level due to the peripartum stress is one of the risk factors of postpartum bovine uterine infections. Selenium is a trace element that elicits anti-inflammation and antioxidation properties. This study aimed to reveal the modulatory effect of selenium on the inflammatory response of primary bovine endometrial stromal cells in the presence of high-level cortisol. The cells were subjected to lipopolysaccharide to establish cellular inflammation. The mRNA expression of toll-like receptor 4 (TLR4), proinflammatory factors, and selenoproteins was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blot and immunofluorescence.

RESULTS

The pretreatment with sodium selenite (2 and 4 µΜ) resulted in a down-regulation of TLR4 and genes encoding proinflammatory factors, including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor α, cyclooxygenase 2, and inducible nitric oxide synthase. Selenium inhibited the activation of NF-κB and the phosphorylation of mitogen-activated protein kinase kinase, extracellular signal-regulated kinase, p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase. The suppression of those genes and pathways by selenium was more significant in the presence of high cortisol level (30 ng/mL). Meanwhile the gene expression of glutathione peroxidase 1 and 4 was promoted by selenium, and was even higher in the presence of cortisol and selenium.

CONCLUSIONS

The anti-inflammatory action of selenium is probably mediated through NF-κB and MAPK, and is augmented by cortisol in primary bovine endometrial stromal cells.

The Effect of Selenium on Endometrial Repair in Goats with Endometritis at High Cortisol Levels

Endometritis is a common postpartum disease of female animals that causes significant losses to the goat industry. High levels of cortisol induced by various stresses after delivery severely inhibit innate immunity and tissue repair. The repair ability of the endometrium is closely related to the reproductive performance of goats. Selenium (Se) is an essential trace element in animals that has powerful antioxidant and immunity-enhancing functions. In this study, we established a goat model of endometritis at high cortisol (Hydrocortisone) levels to investigate the effect of Se (supplement additive) on endometrial repair. The results showed that the clinical symptoms, %PMN in uterine secretions, morphological endometrial damage, and the gene expression of BAX were reduced in the goats with Se supplementation compared with those in the model group. Se increased the gene expression of BCL2, VEGFA, TGFB1, and PCNA and activated the PI3K/AKT and Wnt/β-catenin signaling pathways in goats with Se supplementation. In conclusion, Se reduced the inflammatory response, increased the proliferation, and decreased the apoptosis of endometrial cells to promote endometrial tissue repair in goats with endometritis at high cortisol levels. It probably achieved this effect of promoting repair by activating the Wnt/β-catenin and PI3K/AKT pathways and affecting the gene expression of VEGFA, TGFB1, PCNA, BCL2, and BAX.

Up-regulation of inflammatory, oxidative stress, and apoptotic mediators via inflammatory, oxidative stress, and apoptosis-associated pathways in bovine endometritis

Endometritis is the inflammation of the endothelial lining of the uterine lumen and is multifactorial in etiology. Escherichia (E.) coli is a Gram-negative bacteria, generally considered as a primary causative agent for bovine endometritis. Bovine endometritis is characterized by the activation of Toll-like receptors (TLRs) by E. coli, which in turn triggers inflammation, oxidative stress, and apoptosis. The objective of this study was to investigate the gene expression of inflammatory, oxidative stress, and apoptotic markers related to endometritis in the uteri of cows. Twenty uterine tissues were collected from the abattoir. Histologically, congestion, edema, hyperemia, and hemorrhagic lesions with massive infiltration of neutrophil and cell necrosis were detected markedly (P < 0.05) in infected uterine samples. Additionally, we identify E. coli using the ybbW gene (177 base pairs; E. coli-specific gene) from infected uterine samples. Moreover, qPCR and western blot results indicated that TLR2, TLR4, proinflammatory mediators, and apoptosis-mediated genes upregulated except Bcl-2, which is antiapoptotic, and there were downregulations of oxidative stress-related genes in the infected uterine tissue. The results of our study suggested that different gene expression regimes related to the immune system reflex were activated in infected uteri. This research gives a novel understanding of active immunological response in bovine endometritis.

Protective effects of maternal administration of total saponins of Codonopsis pilosula in the mice offspring following diarrhea: role of immune function, antioxidant function, and intestinal inflammatory injury

Total saponins of Codonopsis (TSC) are a kind of critical bioactive substances in Codonopsis, which have anti-inflammatory, antioxidant, anti-ulcer, immunomodulatory effects, and protective effects on ulcerative enteritis. In this study, TSC (3.75 mL/kg, gavage) was administered once a day to 13-day gestation Kunming mice for 5 days. On day 13 of birth, the offspring were given Escherichia coli solution (0.15 mL/mouse, intraperitoneal injection) and senna leaf decoction (0.15 mL/mouse, gavage) once a day for 6 days. The results showed that gestation maternal administration of TSC effectively reduced the diarrhea index, increased the content of sIgA, IgG, SOD, and GSH, inhibited the TLR4/MyD88/NF-κB pathway in the intestine, reduced the expression of inflammatory factors, and alleviated intestinal injury in the littermates. The results provided a critical reference for the clinical application of TSC to control diarrhea in animal offspring.

Nuciferine protects against lipopolysaccharide-induced endometritis via inhibiting ferroptosis and modulating AMPKα/mTOR/HIF-1α signaling axis

Nuciferine (NF) is an alkaloid isolated from Nelumbo nucifera and has been reported to exhibit a wide range of pharmacological effects. However, whether NF treatment exhibits a protective effect in endometritis remains unclear. Here, the protective effects of NF on lipopolysaccharide (LPS)-induced endometritis in mice were investigated in our research. The results showed that NF significantly reversed the uterine histopathological changes, inflammatory factor levels and myeloperoxidase (MPO) activity caused by LPS. Furthermore, we found that NF administration improved the reproductive capacity of mice with endometritis. Mechanistically, the expression of MyD88/nuclear factor-kappa B (NF-κB) and MAPK-related proteins in uterine tissue were decreased by NF treatment. Moreover, we observed the occurrence of ferroptosis in the LPS-induced endometritis mouse model, which was noticeably inhibited by NF treatment. In addition, we showed that NF exhibited anti-endometritis activity by modulating AMPKα/mTOR/HIF1α signaling axis. Finally, the molecular mechanism of the NF anti-inflammatory effect was clarified in mouse endometrial epithelial cells (mEECs). NF inhibited the releases of pro-inflammatory factors in LPS-induced mEECs via inhibiting NF-κB signaling pathway. All these findings suggest that NF may ameliorate LPS-induced endometritis caused by LPS, the mechanism of action is related to the ferroptosis, MyD88/NF-κB, MAPK and AMPKα/mTOR/HIF1α signaling pathway.

Low let-7d microRNA levels in chick embryos enhance innate immunity against Mycoplasma gallisepticum by suppressing the mitogen-activated protein kinase pathway

Chick embryos are a valuable model for studying immunity and vaccines. Therefore, it is crucial to investigate the molecular mechanism of the Mycoplasma gallisepticum (MG)-induced immune response in chick embryos for the prevention and control of MG. In this study, we screened for downregulated let-7d microRNA in MG-infected chicken embryonic lungs to explore its involvement in the innate immune mechanism against MG. Here, we demonstrated that low levels of let-7d are a protective mechanism for chicken embryo primary type II pneumocytes (CP-II) in the presence of MG. Specifically, we found that depressed levels of let-7 in CP-II cells reduced the adhesion capacity of MG. This suppressive effect was achieved through the activated mitogen-activated protein kinase phosphatase 1 (MKP1) target gene and the inactivated mitogen-activated protein kinase (MAPK) pathway. Furthermore, MG-induced hyperinflammation and cell death were both alleviated by downregulation of let-7d. In conclusion, chick embryos protect themselves against MG infection through the innate immune molecule let-7d, which may result from its function as an inhibitor of the MAPK pathway to effectively mitigate MG adhesion, the inflammatory response and cell apoptosis. This study may provide new insight into the development of vaccines against MG.

UFM1 inhibits the activation of the pyroptosis in LPS-induced goat endometritis

Infertility, abortion, and stillbirth caused by endometritis are the main factors affecting fertility in ruminants. Lipopolysaccharide (LPS)-mediated inflammation is the main cause of endometritis. Toll-like receptor 4 (TLR4) pathway and pyroptosis play an important role in the inflammation, but the underlying mechanism is still unclear. Previous studies have reported that UFMylation, a ubiquitin-like post-translational modifier, plays an important regulatory role in inflammation via the TLR4 pathway; however, its relationship with pyroptosis is still unclear. Our result showed that LPS induced inflammation by activating the TLR4 pathway and pyroptosis in goat endometrial epithelial cells (gEECs). We also found that TAK-242,a specific inhibitor of the TLR4 pathway, inhibited the pyroptosis pathway. In addition, with an increased LPS treatment time, ubiquitin-folding modifier factor 1 (UFM1) conjugated proteins were highly expressed in gEECs. Moreover, overexpression of UFM1 inhibited LPS-induced activation of the TLR4 pathway and pyroptosis, whereas si-UFM1 produced contrasting results. After inhibiting the TLR4 pathway, si-UFM1 could not upregulate the expression of nod-like receptor family protein 3 (NLRP3), cleavage caspase-1, or cleavage gasdermin D (GSDMD). In conclusion, these results suggest that UFM1 inhibits pyroptosis activation in LPS-induced gEECs through the TLR4 pathway.

Oxycodone Alleviates Endometrial Injury via the TLR4/NF-κB Pathway

Endometrial injury is a common female disease. This study was designed to illustrate the effects of oxycodone on mifepristone-induced human endometrial stromal cells (hEndoSCs) injury and delineate the underlying molecular mechanism. hEndoSCs were stimulated with mifepristone to generate the endometrial injury in vitro model. hEndoSCs viability, cytotoxicity, and apoptosis were measured by methyl thiazolyl tetrazolium (MTT) assay, lactate dehydrogenase assay (LDH), and flow cytometry (FCM) analysis, respectively. Meanwhile, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot assay were conducted to evaluate gene and protein expressions. The secretions of inflammatory cytokines (TNF-α, IL-1β, and IL-6) were measured using enzyme-linked immunosorbent assay (ELISA). The data revealed that mifepristone exposure memorably inhibited hEndoSCs viability and promoted cell apoptosis and inflammatory cytokines secretion, and oxycodone had no cytotoxicity on hEndoSCs. Oxycodone increased hEndoSCs growth, blocked cell apoptosis, enhanced Bcl-2 expression, reduced Bax levels, and decreased the secretion of inflammatory cytokines in mifepristone-induced hEndoSCs, exhibiting the protective effects in endometrial injury. In addition, the TLR4/NF-κB pathway-related protein levels (TLR4 and p-p65) in mifepristone-treated hEndoSCs were enhanced, while these enhancements were inhibited by oxycodone treatment. In conclusion, oxycodone exhibited the protective role in mifepristone-triggered endometrial injury via inhibiting the TLR4/NF-κB signal pathway.

Sheep β-Defensin 2 Regulates Escherichia coli F17 Resistance via NF-κB and MAPK Signaling Pathways in Ovine Intestinal Epithelial Cells

Simple Summary

This study was conducted to explore the antibacterial ability of sheep β-defensin 2 (SBD-2) against E. coli F17 infection in ovine intestinal epithelial cells (OIECs). Our data revealed that E. coli F17 induces SBD-2 expression in OIECs in vitro, which appears to be mediated through the activation of the signaling pathways NF-κB and MAPK. Our results provide a novel insight for the functionality of SBD-2, which could be useful for developing anti-infective drugs and/or breeding for E. coli diarrhea disease-resistant sheep.

Abstract

Escherichia coli (E. coli) F17 is a member of enterotoxigenic Escherichia coli, which can cause massive diarrhea and high mortality in newborn lambs. β-defensin is mainly produced by the epithelial tissue of the gastrointestinal tract in response to microbial infection. However, the molecular mechanism of sheep β-defensin 2 (SBD-2) against E. coli F17 remains unclear. This study aims to reveal the antibacterial ability of SBD-2 against E. coli F17 infection in sheep. Firstly, we established the culture system of ovine intestinal epithelial cells (OIECs) in vitro, treated with different concentrations of E. coli F17 for an indicated time. Secondly, we performed RNA interference and overexpression to investigate the effect of SBD-2 expression on E. coli F17 adhesion to OIECs. Finally, inhibitors of NF-κB and MAPK pathways were pre-treated to explore the possible relationship involving in E. coli F17 infection regulating SBD-2 expression. The results showed that E. coli F17 markedly (p < 0.01) upregulated the expression levels of SBD-2 mRNA and protein in a concentration- and time-dependent manner. Overexpression of SBD-2 contributed to enhancing E. coli F17 resistance in OIECs, while silencing SBD-2 dramatically improved the adhesion of E. coli F17 to OIECs (p < 0.05 or p < 0.01). Furthermore, E. coli F17 stimulated SBD-2 expression was obviously decreased by pre-treatment with NF-κB inhibitor PDTC, p38 MAPK inhibitor SB202190 and ERK1/2 MAPK inhibitor PD98095 (p < 0.05 or p < 0.01). Interestingly, adhesion of E. coli F17 to OIECs were highly enhanced by pre-treated with PDTC, SB202190 and PD98095. Our data suggested that SBD-2 could inhibit E. coli F17 infection in OIECs, possibly through NF-κB and MAPK signaling pathways. Our results provide useful theoretical basis on developing anti-infective drug and breeding for E. coli diarrhea disease-resistant sheep.

Interaction between stress hormones and phagocytic cells and its effect on the health status of dairy cows: A review

Dairy cows are exposed to various stressors during their production cycle that makes them more susceptible to various diseases. Phagocytes (neutrophils and macrophages) are important soldiers of the innate immune system. Neutrophils are the first responders to an inflammatory response and stress and kill pathogens by generating reactive oxygen species and by the release of various antimicrobial peptides, enzymes, neutrophil extracellular trap formation, etc. Macrophages, the other phagocytes, are also the cleanup crew for the innate immune system that removes debris, pathogens, and dead neutrophils later on after an inflammatory response. The neuroendocrine system along with phagocytes exhibits an immunomodulatory potential during stressful conditions. Neuroendocrine system directly affects the activity of phagocytes by communicating bidirectionally through shared receptors and messenger molecules such as hormones, neurotransmitters, or cytokines. Different immune cells may show variable responses to each hormone. Short time exposure to stress can be beneficial, but repeated or extended exposure to stress may be detrimental to the overall health and well-being of an animal. Although some stresses associated with farming practices in dairy cows are unavoidable, better understanding of the interactions occurring between various stress hormones and phagocytic cells can help to reduce stress, improve productivity and animal welfare. This review highlights the role played by various stress hormones in modulating phagocytic cell performance of dairy cattle under inflammatory conditions.