Ginsenoside Rb1 Mitigates Escherichia coli Lipopolysaccharide-Induced Endometritis through TLR4-Mediated NF-κB Pathway.
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ABSTRACT:
SUBMITTER: Shaukat A
PROVIDER: S-EPMC8659231 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The purpose of this study was to investigate the effects of thymol on lipopolysaccharide (LPS)-induced inflammatory responses and to clarify the potential mechanism of these effects. LPS-induced mouse endometritis was used to confirm the anti-inflammatory action of thymol in vivo. RAW264.7 cells were used to examine the molecular mechanism and targets of thymol in vitro. In vivo, thymol markedly alleviated LPS-induced pathological injury, myeloperoxidase (MPO) activity, and the production of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in mice. Further studies were performed to examine the expression of the Toll-like receptor 4 (TLR4) -mediated nuclear factor-κB (NF-κB) pathway. These results showed that the expression of the TLR4-mediated NF-κB pathway was inhibited by thymol treatment. In vitro, we observed that thymol dose-dependently inhibited the expression of TNF-α, IL-1β, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW264.7 cells. Moreover, the results obtained from immunofluorescence assays also indicated that thymol dose-dependently suppressed LPS-induced reactive oxygen species (ROS) production. Silencing of TLR4 inhibited NF-κB pathway activation. Furthermore, H2O2 treatment increased the phosphorylation of p65 and IκBα, which were decreased when treated with N-acetyl cysteine or thymol. In conclusion, the anti-inflammatory effects of thymol are associated with activation of the TLR4 or ROS signaling pathways, contributing to NF-κB activation, thereby alleviating LPS-induced oxidative and inflammatory responses.
| S-EPMC5386742 | biostudies-literature
Project description:ObjectiveThe aim of this study was to investigate the anti-inflammatory effect of Rosiglitazone (RGZ) on lipopolysaccharide (LPS) -induced Endometritis and explore its possible mechanism.MethodsThe preventive and therapeutic effects of RGZ on Endometritis were studied in vivo and in vitro. A total of 40 female C57BL/6 mice were randomly divided into the following 4 groups: RGZ+LPS, RGZ control, LPS and DMSO control. The mice uterine tissue sections were performed with HE and immunohistochemical staining. Human endometrial stromal cells (HESCs) were cultured, and different concentrations of LPS stimulation groups and RGZ and/or a TLR4 signaling inhibitor TAK-242 pretreatment +LPS groups were established to further elucidate the underlying mechanisms of this protective effect of RGZ.ResultsThe HE results in mice showed that RGZ+LPS group had less tissue loss than LPS group. Immunohistochemical staining (IHC) results showed that the expression of TLR4 after RGZ treatment was significantly lower than that in LPS group. These findings suggested that RGZ effectively improves the pathological changes associated with LPS-induced endometritis by inhibiting TLR4. Reverse transcription-polymerase chain reaction and western blot analysis demonstrated that RGZ pretreatment suppresses the expression of Toll-like receptor 4 (TLR4) and its downstream activation of nuclear factor-κB (NF-κB). In vitro, RGZ inhibited LPS-stimulated expression of proinflammatory cytokines in a dose-dependent manner and also downregulated LPS induced toll-like receptor 4 (TLR4) expression and inhibited phosphorylation of LPS-induced nuclear transcription factor-kappa B (NF-κB) P65 protein.ConclusionsThese results suggest that RGZ may inhibit LPS-induced endometritis through the TLR4-mediated NF-κB pathway.
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Project description:Catalpol is the main active ingredient of an extract from Radix rehmanniae, which in a previous study showed a protective effect against various types of tissue injury. However, a protective effect of catalpol on uterine inflammation has not been reported. In this study, to investigate the protective mechanism of catalpol on lipopolysaccharide (LPS)-induced bovine endometrial epithelial cells (bEECs) and mouse endometritis, in vitro and in vivo inflammation models were established. The Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway and its downstream inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), western blot (WB), and immunofluorescence techniques. The results from ELISA and qRT-PCR showed that catalpol dose-dependently reduced the expression of pro-inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin (IL)-1β, and IL-6, and chemokines such as C-X-C motif chemokine ligand 8 (CXCL8) and CXCL5, both in bEECs and in uterine tissue. From the experimental results of WB, qRT-PCR, and immunofluorescence, the expression of TLR4 and the phosphorylation of NF-κB p65 were markedly inhibited by catalpol compared with the LPS group. The inflammatory damage to the mouse uterus caused by LPS was greatly reduced and was accompanied by a decline in myeloperoxidase (MPO) activity. The results of this study suggest that catalpol can exert an anti-inflammatory impact on LPS-induced bEECs and mouse endometritis by inhibiting inflammation and activation of the TLR4/NF-κB signaling pathway.
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Project description:BackgroundAtherosclerosis is a chronic degenerative disease of the arteries and is thought to be one of the most common causes of death globally. In recent years, the functions of adventitial fibroblasts in the development of atherosclerosis and tissue repair have gained increased interests. LPS can increase the morbidity and mortality of atherosclerosis-associated cardiovascular disease. Although LPS increases neointimal via TLR4 activation has been reported, how LPS augments atherogenesis through acting on adventitial fibroblasts is still unknown. Here we explored lipid deposition within adventitial fibroblasts mediated by lipopolysaccharide (LPS) to imitate inflammatory conditions.ResultsIn our study, LPS enhanced lipid deposition by the up-regulated expression of adipose differentiation-related protein (ADRP) as the silencing of ADRP abrogated lipid deposition in LPS-activated adventitial fibroblasts. In addition, pre-treatment with anti-Toll-like receptor 4 (TLR4) antibody diminished the LPS-induced lipid deposition and ADRP expression. Moreover, LPS induced translocation of nuclear factor-κB (NF-κB), which could markedly up-regulate lipid deposition as pre-treatment with the NF-κB inhibitor, PDTC, significantly reduced lipid droplets. In addition, the lowering lipid accumulation was accompanied with the decreased ADRP expression. Furthermore, LPS-induced adventitial fibroblasts secreted more monocyte chemoattractant protein (MCP-1), compared with transforming growth factor-β1 (TGF-β1).ConclusionsTaken together, these results suggest that LPS promotes lipid accumulation via the up-regulation of ADRP expression through TLR4 activated downstream of NF-κB in adventitial fibroblasts. Increased levels of MCP-1 released from LPS-activated adventitial fibroblasts and lipid accumulation may accelerate monocytes recruitment and lipid-laden macrophage foam cells formation. Here, our study provides a new explanation as to how bacterial infection contributes to the pathological process of atherosclerosis.
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Project description:Lipopolysaccharide (LPS) as a major component of Escherichia coli cell wall can cause inflammation and cell death. Dihydromyricetin (ampelopsin, DHM) is a natural flavonoid compound with anti-inflammatory, anti-oxidant and anti-bacterial effects. The preventive effects of DHM against ileum injury remain unclear. Here, we explored the protective role of DHM against LPS-induced ileum injury in chickens. In this study, DHM significantly attenuated LPS-induced alteration in diamine oxidase, malondialdehyde, reduced glutathione, glutathione peroxidase and superoxide dismutase levels in chicken plasma and ileum. Histology evaluation showed that the structure of blood vessels in ileum was seriously fragmented and presence of necrotic tissue in the lumen in the LPS group. Scanning electron microscopic observation revealed that the surface of the villi was rough and uneven, the structure was chaotic, and the normal finger shape was lost in the LPS group. In contrast, 0.05% and 0.1% DHM treatment partially alleviated the abnormal morphology. Additionally, DHM maintained the barrier function by restoring the protein expression of occludin, claudin-1 and zonula occludens protein-1. DHM inhibited apoptosis through the reduction of the expression of bax and caspase-3 and restored the expression of bcl-2. Importantly, DHM could reduce ileum NLR family pyrin domain-containing 3 (NLRP3), caspase-1, interleukin (IL)-1? and IL-18 expression to protect tissues from pyroptosis and inhibited toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-?B) signalling pathway. In summary, DHM attenuated the ileum mucosal damage, oxidative stress and apoptosis, maintained barrier function, inhibited NLRP3 inflammasome and TLR4/NF-?B signalling pathway activation triggered by Escherichia coli LPS.
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Project description:As a kind of potent stimulus, lipopolysaccharide (LPS) has the ability to cause cell damage by activating toll-like receptor(TLR)4, then nuclear factor kappa B (NF-κB) translocates into the nucleus and changes the expression of related inflammatory genes. Baicalin is extracted from Radix Scutellariae, which possesses anti-inflammation, antioxidant and antibacterial properties. However, the effects of it on LPS-induced liver inflammation have not been fully elucidated. This study aims to investigate the anti-inflammatory effects of Baicalin on the LPS-induced liver inflammation and its underlying molecular mechanisms in chicken. The results of histopathological changes, serum biochemical analysis, NO levels and myeloperoxidase activity showed that Baicalin pretreatment ameliorated LPS-induced liver inflammation. ELISA and qPCR assays showed that Baicalin dose-dependently suppressed the production of IL-1β, IL-6, and TNF-α. Furthermore, the mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were significantly decreased by Baicalin. TLR4 is an important sensor in LPS infection. Molecular studies showed that the expression of TLR4 was inhibited by Baicalin pretreatment. In addition, Baicalin pretreatment inhibited NF-kB signaling pathway activation. All results demonstrated the protective effects of Baicalin pretreatment against LPS-induced liver inflammation in chicken via negative regulation of inflammatory mediators through the down-regulation of TLR4 expression and the inhibition of NF-kB activation.
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Project description:Resveratrol (RSV) is a natural compound exhibiting anti-inflammatory effect, but the anti-inflammatory mechanism has not been fully understood. This study is aimed to evaluate the anti-inflammatory activity and mechanism of RSV in lipopolysaccharides-induced rats' model. The visceral wet/dry weight ratios and the changes of hematologic and biochemical indices indicated that LPS- stimulation mainly caused damages to liver and lung, while pretreatment with RSV could alleviate the lesions. The cytokine assays showed that RSV could markedly decrease the production of proinflammatory mediators and cytokines (IL-1, IL-1β, IL-6, NO, iNOS and COX-2), and increase the expression of anti-inflammatory mediator (IL-10). RSV could inhibit TLR4 signaling pathway by down-regulating the mRNA levels of MyD88 and TRAF6, and suppressing the TLR4 protein. RSV could inhibit the signaling cascades of NF-κBp65 and MAPKs through down-regulating the mRNA levels of IκBα, p38MAPK, JNK, ERK1, ERK2 and ERK5 in liver and lung, and suppressing the dynamic changes of proteins and phosphorylated proteins including IκBα, NF-κBp65, p38MAPK, JNK, ERK1/2 and ERK5 from tissue's cytoplasm to nucleus. In conclusion, RSV possessed a therapeutic effect on LPS-induced inflammation in rats and the mechanism mainly attributed to suppressing the signaling cascades of NF-κBp65 and MAPKs by inhibiting the TLR4 signaling pathway.
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Project description:BackgroundPersistent endometritis caused by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which compromises animal welfare and delays or prevents pregnancy. The microRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis has not been thoroughly elucidated to date.MethodsIn this study, the endometrium of cows diagnosed with endometritis was harvested for bacterial culture and Gram staining to evaluate bacterial contamination of the uterus. Based on this, a bovine endometrial epithelial cell (BEND) inflammation model and a mouse model stimulated with lipopolysaccharide (LPS) in vitro and in vivo were constructed. Cell viability was assessed by CCK-8, trypan blue staining, and flow cytometry. H&E was applied to histopathological analysis. Immunohistochemical, immunofluorescence, qRT-PCR, and western blot assays were performed to measure the mRNA and protein expression of relevant genes. Online databases, plasmid construction, and dual-luciferase reporter gene assays were used to predict and validate the interaction between miR-34a and its target gene LGR4. Finally, mice were injected vaginally with a local antagomir to validate the role of miR-34a in murine uterine inflammation.ResultsIn this study, we observed that Gram-negative bacteria, represented by Escherichia coli, are the predominant pathogenic agents responsible for the recurrent occurrence of endometritis in dairy cows. Further, miR-34a was found to repress the expression of LGR4 by targeting the 3' untranslated region (3'UTR) of LGR4. miR-34a was upregulated in bovine uterine tissues and bovine endometrial epithelial cells stimulated with LPS. miR-34a induced the release of the proinflammatory cytokines IL-1β, IL-6, and TNF-α by activating the phosphorylation of NF-κB p65. Furthermore, IL-1β upregulated miR-34a transcription and downregulated LGR4 expression in an IL-1β-dependent manner.ConclusionsTaken together, our study confirmed that miR-34a is regulated by IL-1β and suppresses the level of the LGR4 3'UTR, which in turn exacerbates the inflammatory response. Thus, the knockdown of miR-34a might be a new direction for the treatment of endometritis.
| S-EPMC8422159 | biostudies-literature
Project description:Icariin (ICA) is a naturally occurring phytochemical agent primarily extracted from Epimedium Brevicornum Maxim (Family Berberidaceae) with a broad spectrum of bioactivities. Endometritis is a uterine disease that causes enormous losses in the dairy industry worldwide. In this study, anti-inflammatory and anti-oxidant properties of ICA were investigated against lipopolysaccharide (LPS)-induced endometritis in mice to investigate possible underlying molecular mechanisms. Sixty heathy female Kunming mice were randomly assigned to four groups (n = 15), namely control, LPS, LPS + ICA, and ICA groups. The endometritis was induced by intrauterine infusion of 50 µL of LPS (1 mg/mL). After 24 h of onset of LPS-induced endometritis, ICA groups were injected thrice by ICA intraperitoneally six hours apart. Histopathological examination, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), western blotting, and immunohistochemistry were used in this study. Histological alterations revealed that ICA markedly mitigated uterine tissue injury caused by LPS. The results showed that the ICA inhibited the production of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and boosted the production of anti-inflammatory cytokines (IL-10). Additionally, ICA modulated the expression of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (Gpx1) induced by LPS. The administration of ICA significantly (p < 0.05) improved the mRNA and protein expression of Toll-like receptor (TLR) 4. The western blotting and ELISA finding revealed that the ICA repressed LPS-triggered NF-κB pathway activation. Moreover, ICA improved the antioxidant defense system via activation of the Nrf2 pathway. The results revealed that ICA up-regulated the mRNA and protein expression of Nuclear erythroid-2-related factor (Nrf2), NAD(P)H: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and glutamate-cysteine ligase catalytic subunit (GCLC) under LPS exposure. Conclusively, our findings strongly suggested that ICA protects endometritis caused by LPS by suppressing TLR4-associated NF-κB and Nrf2 pathways. Altogether, these innovative findings may pave the way for future studies into the therapeutic application of ICA to protect humans and animals against endometritis.
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Project description:It is currently believed that inflammation plays a central role in the pathophysiology of atherosclerosis. Oxidative stress and redox-sensitive transcription factors are implicated in the process. Ginsenoside Rb1, a major active ingredient in processed Radix notoginseng, has attracted widespread attention because of its potential to improve cardiovascular function. However, the effects of ginsenoside Rb1 on tumor necrosis factor-α (TNF-α)-induced vascular endothelial cell injury and the underlying molecular mechanisms have never been studied. This study showed that TNF-α-induced oxidative stress, inflammation and apoptosis in human umbilical vein endothelial cells (HUVECs) could be attenuated by ginsenoside Rb1 pretreatment. Using JC-1, Annexin V/PI and TUNEL staining, and a caspase-3 activity assay, we found that Rb1 provided significant protection against TNF-α-induced cell death. Furthermore, Rb1 pretreatment could inhibit TNF-α-induced ROS and MDA production; increase the activities of SOD, CAT, and GSH-Px; and decrease the levels of IL-1β, IL-6, VCAM-1, ICAM-1, VEGF, MMP-2 and MMP-9. Importantly, the cytoprotective effects of Rb1 were correlated with NF-κB signaling pathway inhibition. Additionally, we found that Rb1 may suppress the NF-κB pathway through p-38 and JNK pathway activation, findings supported by the results of our experiments involving anisomycin (AM), a JNK and p38 activator. In conclusion, this study showed that ginsenoside Rb1 protects HUVECs from TNF-α-induced oxidative stress and inflammation by inhibiting JNK and p38. This inhibition suppressed NF-κB signaling and down-regulated the expression of inflammatory factors and apoptosis-related proteins.
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