AIM To determine the effects of ω-3 fatty acids(ω-3FA) on the toll-like receptor 4(TLR4)/nuclear factor κB p56(NF-κBp56) signal pathway in the lungs of rats with severe acute pancreatitis(SAP).METHODS A total of 5...AIM To determine the effects of ω-3 fatty acids(ω-3FA) on the toll-like receptor 4(TLR4)/nuclear factor κB p56(NF-κBp56) signal pathway in the lungs of rats with severe acute pancreatitis(SAP).METHODS A total of 56 Sprague-Dawley rats were randomly divided into 4 groups: control group, SAP-saline group, SAP-soybean oil group and SAP-ω-3FA group. SAP was induced by the retrograde infusion of sodium taurocholate into the pancreatic duct. The expression of TLR4 and NF-κBp56 in the lungs was evaluated by immunohistochemistry and Western blot analysis. The levels of inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in the lungs were measured by enzyme-linked immunosorbent assay. RESULTS The expression of TLR4 and NF-κBp56 in lungs and of inflammatory cytokines in serum significantly increased in the SAP group compared with the control group(P < 0.05), but was significantly decreased in the ω-3FA group compared with the soybean oil group at 12 and 24 h(P < 0.05).CONCLUSION During the initial stage of SAP, ω-3FA can efficiently lower the inflammatory response and reduce lung injury by triggering the TLR4/NF-κBp56 signal pathway.展开更多
BACKGROUND Jianpi Gushen Huayu Decoction(JPGS)has been used to clinically treat diabetic nephropathy(DN)for many years.However,the protective mechanism of JPGS in treating DN remains unclear.AIM To evaluate the therap...BACKGROUND Jianpi Gushen Huayu Decoction(JPGS)has been used to clinically treat diabetic nephropathy(DN)for many years.However,the protective mechanism of JPGS in treating DN remains unclear.AIM To evaluate the therapeutic effects and the possible mechanism of JPGS on DN.METHODS We first evaluated the therapeutic potential of JPGS on a DN mouse model.We then investigated the effect of JPGS on the renal metabolite levels of DN mice using non-targeted metabolomics.Furthermore,we examined the effects of JPGS on c-Jun N-terminal kinase(JNK)/P38-mediated apoptosis and the inflammatory responses mediated by toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)/NOD-like receptor family pyrin domain containing 3(NLRP3).RESULTS The ameliorative effects of JPGS on DN mice included the alleviation of renal injury and the control of inflammation and oxidative stress.Untargeted metabolomic analysis revealed that JPGS altered the metabolites of the kidneys in DN mice.A total of 51 differential metabolites were screened.Pathway analysis results indicated that nine pathways significantly changed between the control and model groups,while six pathways significantly altered between the model and JPGS groups.Pathways related to cysteine and methionine metabolism;alanine,tryptophan metabolism;aspartate and glutamate metabolism;and riboflavin metabolism were identified as the key pathways through which JPGS affects DN.Further experimental validation showed that JPGS treatment reduced the expression of TLR4/NF-κB/NLRP3 pathways and JNK/P38 pathway-mediated apoptosis related factors.CONCLUSION JPGS could markedly treat mice with streptozotocin(STZ)-induced DN,which is possibly related to the regulation of several metabolic pathways found in kidneys.Furthermore,JPGS could improve kidney inflammatory responses and ameliorate kidney injuries in DN mice via the TLR4/NF-κB/NLRP3 pathway and inhibit JNK/P38 pathwaymediated apoptosis in DN mice.展开更多
Lipopolysaccharide stimulates Toll-like receptor 4 on immune cells to produce immune mediators. Toll-like receptor 4 is also expressed by non-immune cells, which can be stimulated by lipopolysaccharide. However, wheth...Lipopolysaccharide stimulates Toll-like receptor 4 on immune cells to produce immune mediators. Toll-like receptor 4 is also expressed by non-immune cells, which can be stimulated by lipopolysaccharide. However, whether Toll-like receptor 4 is expressed by primary cultured hippocampal neurons and its specific role in lipopolysaccharide-induced neuroinflammation is currently undefined, in this study, Toll-like receptor 4 antibody blocking was used to analyze the Toll-like receptor 4 signaling pathway and changes in inflammation of lipopolysaccharide stimulated hippocampal neurons. Immunofluorescence showed that Toll-like receptor 4 protein was mainly located in the membrane of hippocampal neurons. Quantitative reverse transcription-PCR and western blot assay showed that after stimulation of lipopolysaccharide, the mRNA and protein levels of Toll-like receptor 4 and the mRNA levels of interleukin-ll3 and tumor necrosis factor-（] were significantly increased. In addition, there was increased phosphorylation and degradation of kappa B a inhibitor in the cytosol and increased nuclear factor-KB p65 expression in the nuclei. Pretreatment with Toll-like receptor 4 antibody could almost completely block this increase. These experimental findings indicate that lipopolysaccharide participates in neuroinflammation by stimulating Toll-like receptor 4/nuclear factor-KB pathway in hippocampal neurons, which may be both ＂passive victims＂ and ＂activators＂ of neuroinflammation.展开更多
Background Restoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury （IRI）. Toll-like receptor 4 （TLR4）, expressed on sev...Background Restoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury （IRI）. Toll-like receptor 4 （TLR4）, expressed on several liver cell types, and the nuclear factor-kappa B （NF-KB） signaling pathway are crucial to mediating hepatic inflammatory response. Because IRI is essentially a kind of profound acute inflammatory reaction evoked by many kinds of danger signals, we investigated TLR4/NF-KB signaling pathway activation in a murine model of partial hepatic IRI. Methods Wild-type mice （WT, C3H/HeN） or TLR4 mutant mice （C3H/HeJ） were subjected to 45 minutes of partial hepatic ischemia followed by 1 hour, 3 hours of reperfusion. Sham group accepted the same procedure without the obstruction of blood supply. At the end of reperfusion, the compromise of liver function and the histological change of liver sections were measured as the severity of liver injury. The level of endotoxin in the portal vein was measured by limulus assay. NF-KB activation was determined by electrophoretic mobility shift assay （EMSA）. The levels of tumor necrosis factor-a （TNF-a） and intedeukin-1β （IL-1β） in systemic blood after hepatic IRI were assessed by enzyme-linked immunosorbent assay （ELISA）. Results The compromise of liver function and the morphological injuries in mutant mice were relieved more markedly than those in WT mice after partial hepatic IRI. NF-KB activation in WT mice was stronger than that in TLR4 mutant mice, and both were stronger than those in the sham operated mice （P〈0.01）. Endotoxin in each group was undetectable. The levels of TNF-α and IL-1β in systemic blood were elevated in both strains, but lower in the sham operated group. These mediators were significantly decreased in TLR4 mutant mice compared with those in WT mice （P〈0.01）. Conclusions The TLR4/NF-KB signaling pathway may mediate hepatic IRI triggered by endogenous danger signals. Inhibition of the TLR4/NF-KB pathway may be a potential therapeutic target for attenuating ischemia/reperfusion-induced tissue damage in some clinical settings.展开更多
Background Inflammation and immunity play a vital role in the pathogenesis of early brain injury after subarachnoid hemorrhage （SAH）. Nuclear factor-kappa B （NF-κB） regulates many genes essential for inflammation...Background Inflammation and immunity play a vital role in the pathogenesis of early brain injury after subarachnoid hemorrhage （SAH）. Nuclear factor-kappa B （NF-κB） regulates many genes essential for inflammation and immunity and is activated by toll-like receptor （TLR）. This study aimed to detect the expression of the toll-like receptor 4/nuclear factor-kappa B （TLR4/NF-κB） signaling in the rat brain after early SAH. Methods The rats were decapitated and their brains were removed at 0, 2, 4, 6, 12, 24 and 48 hours after a single injection of blood into the prechiasmatic cistern, mRNA expression of TLR4 was measured by Taqman real-time RT-PCR, and protein expression by immunohistochemistry and Western blotting. NF-κB activity and concentrations of tumor necrosis factor-alpha （TNF-α）, interleukin-lbeta （IL-1β） and interleukin-6 （IL-6） were measured by enzyme-linked immunosorbent assay （ELISA）. Results TaqMan real-time RT-PCR and Western blotting identified a biphasic change in TLR4 expression in both mRNA and protein： an initial peak （2-6 hours） and a sustained elevation （12-48 hours）. Immunohistochemical staining showed the inducible expression of TLR4-like immunoreactions predominantly in glial cells and vascular endothelium. A similar biphasic change in the activation of NF-κB subunit p65 as well as the production of NF-κB-regulated proinflammatory cytokines （TNF-α, IL-1β and IL-6） were detected by ELISA. Conclusions These data suggest that experimental SAH induces significant up-regulation of TLR4 expression and the NF-κB signaling in early brain injury. Activation of the TLR4/NF-κB signaling may regulate the inflammatory responses after SAH.展开更多
Nuclear factor kappa B（NF-κB） in the spinal cord is involved in pro-infl ammatory cytokine-mediated pain facilitation. However, the role of NF-κB activation in chronic morphine-induced analgesic tolerance and the ...Nuclear factor kappa B（NF-κB） in the spinal cord is involved in pro-infl ammatory cytokine-mediated pain facilitation. However, the role of NF-κB activation in chronic morphine-induced analgesic tolerance and the underlying mechanisms remain unclear. In the present study, we found that the level of phosphorylated NF-κB p65（p-p65） was increased in the dorsal horn of the lumbar 4–6 segments after intrathecal administration of morphine for 7 consecutive days, and the p-p65 was co-localized with neurons and astrocytes. The expression of TNF-α and IL-1β was also increased in the same area. In addition, pretreatment with pyrrolidinedithiocarbamate（PDTC） or SN50, inhibitors of NF-κB, prevented the development of morphine analgesic tolerance and alleviated morphine withdrawal-induced allodynia and hyperalgesia. The increase in TNF-α and IL-1β expression induced by chronic morphine exposure was also partially blocked by PDTC pretreatment. In another experiment, rats receiving PDTC or SN50 beginning on day 7 of morphine injection showed partial recovery of the anti-nociceptive effects of morphine and attenuation of the withdrawal-induced abnormal pain. Meanwhile, intrathecal pretreatment with lipopolysaccharide from Rhodobacter sphae-roides, an antagonist of toll-like receptor 4（TLR4）, blocked the activation of NF-κB, and prevented the development of morphine tolerance and withdrawal-induced abnormal pain. These data indicated that TLR4-mediated NF-κB activation in the spinal cord is involved in the development and maintenance of morphine analgesic tolerance and withdrawalinduced pain hypersensitivity.展开更多
OBJECTIVE： Celastrol has been established as a nuclear factor-κB（NF-κB） activation inhibitor; however, the exact mechanism behind this action is still unknown. Using text-mining technology, the authors predicted ...OBJECTIVE： Celastrol has been established as a nuclear factor-κB（NF-κB） activation inhibitor; however, the exact mechanism behind this action is still unknown. Using text-mining technology, the authors predicted that int erleukin-1 receptor-associated kinases（IRA Ks） are potential celastrol targets, and hypothesized that targeting IRAKs might be one way that celastrol inhibits NF-κB. This is because IRAKs are key molecules for some crucial pathways to activate NF-κB（e.g., the inter leukin-1 receptor（IL-1R）/Toll- like receptor（TLR） superfamily）.METHODS： The human hepatocellular cell line（Hep G2） treated with palmitic acid（PA） was used as a model for stimulating TLR4/NF-κB activation, in order to observe the potential effects of celastrol in IRAK regulation and NF-κB inhibition. The transfection of small interfering RNA was used for down-regulating TLR4, IRAK1 and IRAK4, and the Western blot method was used to detect changes in the protein expressions.RESULTS： The results showed that celastrol could effectively inhibit PA-caused TLR4-dependent NF-κB activation in the Hep G 2 cells; PA also activated IRAKs, which were inhibited by celastrol. Knocking down IRAKs abolished PA-caused NF-κB activation.CONCLUSION： The results for the first time show that targeting IRAKs is one way in which celastrol inhibits NF-κB activation.展开更多
BACKGROUND Our previous studies confirmed that abdominal paracentesis drainage(APD)attenuates intestinal mucosal injury in rats with severe acute pancreatitis(SAP),and improves administration of enteral nutrition in p...BACKGROUND Our previous studies confirmed that abdominal paracentesis drainage(APD)attenuates intestinal mucosal injury in rats with severe acute pancreatitis(SAP),and improves administration of enteral nutrition in patients with acute pancreatitis(AP).However,the underlying mechanisms of the beneficial effects of APD remain poorly understood.AIM To evaluate the effect of APD on intestinal inflammation and accompanying apoptosis induced by SAP in rats,and its potential mechanisms.METHODS SAP was induced in male adult Sprague-Dawley rats by 5%sodium taurocholate.Mild AP was induced by intraperitoneal injections of cerulein(20μg/kg body weight,six consecutive injections).Following SAP induction,a drainage tube connected to a vacuum ball was placed into the lower right abdomen of the rats to build APD.Morphological changes,serum inflammatory mediators,serum and ascites high mobility group box protein 1(HMGB1),intestinal barrier function indices,apoptosis and associated proteins,and toll-like receptor 4(TLR4)signaling molecules in intestinal tissue were assessed.RESULTS APD significantly alleviated intestinal mucosal injury induced by SAP,as demonstrated by decreased pathological scores,serum levels of D-lactate,diamine oxidase and endotoxin.APD reduced intestinal inflammation and accompanying apoptosis of mucosal cells,and normalized the expression of apoptosis-associated proteins in intestinal tissues.APD significantly suppressed activation of the intestinal TLR4 signaling pathway mediated by HMGB1,thus exerting protective effects against SAP-associated intestinal injury.CONCLUSION APD improved intestinal barrier function,intestinal inflammatory response and accompanying mucosal cell apoptosis in SAP rats.The beneficial effects are potentially due to inhibition of HMGB1-mediated TLR4 signaling.展开更多
Background: Existing studies have found that some inflammatory factors cause brain cell damage through the TLR4/NF-κB pathway, and that mild hypothermia has a protective effect on nerve cells. It is not clear whether...Background: Existing studies have found that some inflammatory factors cause brain cell damage through the TLR4/NF-κB pathway, and that mild hypothermia has a protective effect on nerve cells. It is not clear whether the mild hypothermic brain protection is achieved through the TLR4/NF-κB pathway in microglia. Objective: To investigate the impacts of mild hypothermia on lipopolysaccharide (LPS)-mediated TLR4/NF-κB signaling pathway in microglia. Method: The cultured microglia cells in vitro were divided into the NS group and the LPS group at 33?C and 37?C, respectively;quantitative RT-PCR was performed to detect the expressions of TLR4 and NF-κB mRNA in the microglia, Western blot was used to detect the expressions of TLR4 and NF-κB protein in the microglia, and ELISA was performed to detect the levels of tumor necrosis factor α (TNF-α) and interleukin-10 (IL-10) in the culture medium. Results: Under the LPS stimulation, the mRNA and protein expressions of TLR4 and NF-κB at different time points had significant changes between the normothermia group and the mild hypothermia group, in which the expressions in the former group were firstly increased and then decreased, while those in the latter showed a continuous increasing trend (P < 0.01);and the expressions of TNF-α in all the groups presented the trend of first-increasing then-decreasing, while IL-10 exhibited one slow linear increasing trend (P Conclusions: Mild hypothermia could inhibit the mRNA and protein expressions of LPS-mediated TLR4/NF-κB signaling pathway in the microglia, and inhibit the production and release of downstream inflammatory cytokines (TNF-α and IL-10).展开更多
BACKGROUND Budd-Chiari syndrome(BCS)is an uncommon disorder characterized by obstruction of hepatic venous outflow.To date,the exact mechanism underlying hepatic injury derived from the hepatic venous outflow obstruct...BACKGROUND Budd-Chiari syndrome(BCS)is an uncommon disorder characterized by obstruction of hepatic venous outflow.To date,the exact mechanism underlying hepatic injury derived from the hepatic venous outflow obstruction in BCS remains largely unknown.AIM To assess the role of NF-κB-mediated inflammation in BCS-induced liver injury in humans and rats.METHODS A total of 180 rats were randomly assigned into nine groups,including four BCS model groups(1,3,6 and 12 wk),four sham-operated groups(1,3,6 and 12 wk),and a control group.Lipopolysaccharide(LPS)levels in each group were detected by the Tachypleus Amebocyte Lysate assay.The mRNA and protein levels of TLR4,NF-κB,tumor necrosis factor(TNF)-α,interleukin(IL)-2 and interferon(IFN)-γwere quantified.In addition,60 patients with BCS and 30 healthy controls were enrolled,and their blood samples were analyzed.RESULTS Hepatic and plasma LPS levels were significantly increased in rats.The mRNA and protein expression levels of TLR4,NF-κB and inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in liver tissues were significantly higher in the BCS model groups compared with the other two groups.In addition,the model groups(1,3,6 and 12 wk after BCS induction)showed significant differences in the levels of LPS,TLR4,NF-κB,TNF-α,IL-2 and IFN-γ.Notably,there was a significant correlation between the LPS concentrations and mRNA and protein levels of TLR4,NF-κB and inflammatory cytokines.Importantly,it was revealed that the levels of LPS,TLR4,NF-κB and inflammatory cytokines were significantly greater in chronic BCS patients than healthy controls and acute BCS patients.CONCLUSION LPS level is markedly elevated in BCS,in turn activating the TLR4/NF-κB signaling pathway,leading to induction of inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in response to BCS-induced liver injury.展开更多
基金Supported by Jinling Hospital Research Fund,No.2013064
文摘AIM To determine the effects of ω-3 fatty acids(ω-3FA) on the toll-like receptor 4(TLR4)/nuclear factor κB p56(NF-κBp56) signal pathway in the lungs of rats with severe acute pancreatitis(SAP).METHODS A total of 56 Sprague-Dawley rats were randomly divided into 4 groups: control group, SAP-saline group, SAP-soybean oil group and SAP-ω-3FA group. SAP was induced by the retrograde infusion of sodium taurocholate into the pancreatic duct. The expression of TLR4 and NF-κBp56 in the lungs was evaluated by immunohistochemistry and Western blot analysis. The levels of inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in the lungs were measured by enzyme-linked immunosorbent assay. RESULTS The expression of TLR4 and NF-κBp56 in lungs and of inflammatory cytokines in serum significantly increased in the SAP group compared with the control group(P < 0.05), but was significantly decreased in the ω-3FA group compared with the soybean oil group at 12 and 24 h(P < 0.05).CONCLUSION During the initial stage of SAP, ω-3FA can efficiently lower the inflammatory response and reduce lung injury by triggering the TLR4/NF-κBp56 signal pathway.
基金Supported by the Scientific Foundation of Administration of Traditional Chinese Medicine of Hebei Province,China,No.2023257.
文摘BACKGROUND Jianpi Gushen Huayu Decoction(JPGS)has been used to clinically treat diabetic nephropathy(DN)for many years.However,the protective mechanism of JPGS in treating DN remains unclear.AIM To evaluate the therapeutic effects and the possible mechanism of JPGS on DN.METHODS We first evaluated the therapeutic potential of JPGS on a DN mouse model.We then investigated the effect of JPGS on the renal metabolite levels of DN mice using non-targeted metabolomics.Furthermore,we examined the effects of JPGS on c-Jun N-terminal kinase(JNK)/P38-mediated apoptosis and the inflammatory responses mediated by toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)/NOD-like receptor family pyrin domain containing 3(NLRP3).RESULTS The ameliorative effects of JPGS on DN mice included the alleviation of renal injury and the control of inflammation and oxidative stress.Untargeted metabolomic analysis revealed that JPGS altered the metabolites of the kidneys in DN mice.A total of 51 differential metabolites were screened.Pathway analysis results indicated that nine pathways significantly changed between the control and model groups,while six pathways significantly altered between the model and JPGS groups.Pathways related to cysteine and methionine metabolism;alanine,tryptophan metabolism;aspartate and glutamate metabolism;and riboflavin metabolism were identified as the key pathways through which JPGS affects DN.Further experimental validation showed that JPGS treatment reduced the expression of TLR4/NF-κB/NLRP3 pathways and JNK/P38 pathway-mediated apoptosis related factors.CONCLUSION JPGS could markedly treat mice with streptozotocin(STZ)-induced DN,which is possibly related to the regulation of several metabolic pathways found in kidneys.Furthermore,JPGS could improve kidney inflammatory responses and ameliorate kidney injuries in DN mice via the TLR4/NF-κB/NLRP3 pathway and inhibit JNK/P38 pathwaymediated apoptosis in DN mice.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Nantong Applied Research Program,No.k2010036+1 种基金the 2011 Jiangsu Graduated Students' Research and Innovation Program,No.CX2211-0640the Nantong University Graduated Students' Technological and Innovative Program,No.YKC11033
文摘Lipopolysaccharide stimulates Toll-like receptor 4 on immune cells to produce immune mediators. Toll-like receptor 4 is also expressed by non-immune cells, which can be stimulated by lipopolysaccharide. However, whether Toll-like receptor 4 is expressed by primary cultured hippocampal neurons and its specific role in lipopolysaccharide-induced neuroinflammation is currently undefined, in this study, Toll-like receptor 4 antibody blocking was used to analyze the Toll-like receptor 4 signaling pathway and changes in inflammation of lipopolysaccharide stimulated hippocampal neurons. Immunofluorescence showed that Toll-like receptor 4 protein was mainly located in the membrane of hippocampal neurons. Quantitative reverse transcription-PCR and western blot assay showed that after stimulation of lipopolysaccharide, the mRNA and protein levels of Toll-like receptor 4 and the mRNA levels of interleukin-ll3 and tumor necrosis factor-（] were significantly increased. In addition, there was increased phosphorylation and degradation of kappa B a inhibitor in the cytosol and increased nuclear factor-KB p65 expression in the nuclei. Pretreatment with Toll-like receptor 4 antibody could almost completely block this increase. These experimental findings indicate that lipopolysaccharide participates in neuroinflammation by stimulating Toll-like receptor 4/nuclear factor-KB pathway in hippocampal neurons, which may be both ＂passive victims＂ and ＂activators＂ of neuroinflammation.
基金This research was supported by grants from the National Nature Science Foundation of China(No.30200272 and No.30500487)
文摘Background Restoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury （IRI）. Toll-like receptor 4 （TLR4）, expressed on several liver cell types, and the nuclear factor-kappa B （NF-KB） signaling pathway are crucial to mediating hepatic inflammatory response. Because IRI is essentially a kind of profound acute inflammatory reaction evoked by many kinds of danger signals, we investigated TLR4/NF-KB signaling pathway activation in a murine model of partial hepatic IRI. Methods Wild-type mice （WT, C3H/HeN） or TLR4 mutant mice （C3H/HeJ） were subjected to 45 minutes of partial hepatic ischemia followed by 1 hour, 3 hours of reperfusion. Sham group accepted the same procedure without the obstruction of blood supply. At the end of reperfusion, the compromise of liver function and the histological change of liver sections were measured as the severity of liver injury. The level of endotoxin in the portal vein was measured by limulus assay. NF-KB activation was determined by electrophoretic mobility shift assay （EMSA）. The levels of tumor necrosis factor-a （TNF-a） and intedeukin-1β （IL-1β） in systemic blood after hepatic IRI were assessed by enzyme-linked immunosorbent assay （ELISA）. Results The compromise of liver function and the morphological injuries in mutant mice were relieved more markedly than those in WT mice after partial hepatic IRI. NF-KB activation in WT mice was stronger than that in TLR4 mutant mice, and both were stronger than those in the sham operated mice （P〈0.01）. Endotoxin in each group was undetectable. The levels of TNF-α and IL-1β in systemic blood were elevated in both strains, but lower in the sham operated group. These mediators were significantly decreased in TLR4 mutant mice compared with those in WT mice （P〈0.01）. Conclusions The TLR4/NF-KB signaling pathway may mediate hepatic IRI triggered by endogenous danger signals. Inhibition of the TLR4/NF-KB pathway may be a potential therapeutic target for attenuating ischemia/reperfusion-induced tissue damage in some clinical settings.
文摘Background Inflammation and immunity play a vital role in the pathogenesis of early brain injury after subarachnoid hemorrhage （SAH）. Nuclear factor-kappa B （NF-κB） regulates many genes essential for inflammation and immunity and is activated by toll-like receptor （TLR）. This study aimed to detect the expression of the toll-like receptor 4/nuclear factor-kappa B （TLR4/NF-κB） signaling in the rat brain after early SAH. Methods The rats were decapitated and their brains were removed at 0, 2, 4, 6, 12, 24 and 48 hours after a single injection of blood into the prechiasmatic cistern, mRNA expression of TLR4 was measured by Taqman real-time RT-PCR, and protein expression by immunohistochemistry and Western blotting. NF-κB activity and concentrations of tumor necrosis factor-alpha （TNF-α）, interleukin-lbeta （IL-1β） and interleukin-6 （IL-6） were measured by enzyme-linked immunosorbent assay （ELISA）. Results TaqMan real-time RT-PCR and Western blotting identified a biphasic change in TLR4 expression in both mRNA and protein： an initial peak （2-6 hours） and a sustained elevation （12-48 hours）. Immunohistochemical staining showed the inducible expression of TLR4-like immunoreactions predominantly in glial cells and vascular endothelium. A similar biphasic change in the activation of NF-κB subunit p65 as well as the production of NF-κB-regulated proinflammatory cytokines （TNF-α, IL-1β and IL-6） were detected by ELISA. Conclusions These data suggest that experimental SAH induces significant up-regulation of TLR4 expression and the NF-κB signaling in early brain injury. Activation of the TLR4/NF-κB signaling may regulate the inflammatory responses after SAH.
基金supported by grants from the National Natural Science Foundation of China (31171070 and 81171060)
文摘Nuclear factor kappa B（NF-κB） in the spinal cord is involved in pro-infl ammatory cytokine-mediated pain facilitation. However, the role of NF-κB activation in chronic morphine-induced analgesic tolerance and the underlying mechanisms remain unclear. In the present study, we found that the level of phosphorylated NF-κB p65（p-p65） was increased in the dorsal horn of the lumbar 4–6 segments after intrathecal administration of morphine for 7 consecutive days, and the p-p65 was co-localized with neurons and astrocytes. The expression of TNF-α and IL-1β was also increased in the same area. In addition, pretreatment with pyrrolidinedithiocarbamate（PDTC） or SN50, inhibitors of NF-κB, prevented the development of morphine analgesic tolerance and alleviated morphine withdrawal-induced allodynia and hyperalgesia. The increase in TNF-α and IL-1β expression induced by chronic morphine exposure was also partially blocked by PDTC pretreatment. In another experiment, rats receiving PDTC or SN50 beginning on day 7 of morphine injection showed partial recovery of the anti-nociceptive effects of morphine and attenuation of the withdrawal-induced abnormal pain. Meanwhile, intrathecal pretreatment with lipopolysaccharide from Rhodobacter sphae-roides, an antagonist of toll-like receptor 4（TLR4）, blocked the activation of NF-κB, and prevented the development of morphine tolerance and withdrawal-induced abnormal pain. These data indicated that TLR4-mediated NF-κB activation in the spinal cord is involved in the development and maintenance of morphine analgesic tolerance and withdrawalinduced pain hypersensitivity.
基金the Shanghai Gongli Hospital Youth Project (No. 2014GLQN16 for YS and No. 2012GLQN09 for XZ)the Shanghai Pudong District Science and Technology Innovation Project (No. PKJ2013-Y03 for YW)+5 种基金the Shanghai Pudong Youth Talent Project in Medicine (No. PWRq2013-11 for FC)the Shanghai Yang Fan Project (No. 15YF1410800 for FC)the International Science & Technology Cooperation Project of China (Grant 2011DFB30010 for GU)the National Natural Science Foundation of China (No. 81102349 for BP and No. 81400793 for YW)the Shanghai Excellent Academic Leader in Medicine (No. XBR2011054 for DZ)the Shanghai Traditional Chinese Medicine Content Construction Innovation Project (No. ZY3-CCCX-3-7001 for DZ)
文摘OBJECTIVE： Celastrol has been established as a nuclear factor-κB（NF-κB） activation inhibitor; however, the exact mechanism behind this action is still unknown. Using text-mining technology, the authors predicted that int erleukin-1 receptor-associated kinases（IRA Ks） are potential celastrol targets, and hypothesized that targeting IRAKs might be one way that celastrol inhibits NF-κB. This is because IRAKs are key molecules for some crucial pathways to activate NF-κB（e.g., the inter leukin-1 receptor（IL-1R）/Toll- like receptor（TLR） superfamily）.METHODS： The human hepatocellular cell line（Hep G2） treated with palmitic acid（PA） was used as a model for stimulating TLR4/NF-κB activation, in order to observe the potential effects of celastrol in IRAK regulation and NF-κB inhibition. The transfection of small interfering RNA was used for down-regulating TLR4, IRAK1 and IRAK4, and the Western blot method was used to detect changes in the protein expressions.RESULTS： The results showed that celastrol could effectively inhibit PA-caused TLR4-dependent NF-κB activation in the Hep G 2 cells; PA also activated IRAKs, which were inhibited by celastrol. Knocking down IRAKs abolished PA-caused NF-κB activation.CONCLUSION： The results for the first time show that targeting IRAKs is one way in which celastrol inhibits NF-κB activation.
基金Supported by The National Natural Science Foundation of China,No.81772001the National Clinical Key Subject of China,No.41732113
文摘BACKGROUND Our previous studies confirmed that abdominal paracentesis drainage(APD)attenuates intestinal mucosal injury in rats with severe acute pancreatitis(SAP),and improves administration of enteral nutrition in patients with acute pancreatitis(AP).However,the underlying mechanisms of the beneficial effects of APD remain poorly understood.AIM To evaluate the effect of APD on intestinal inflammation and accompanying apoptosis induced by SAP in rats,and its potential mechanisms.METHODS SAP was induced in male adult Sprague-Dawley rats by 5%sodium taurocholate.Mild AP was induced by intraperitoneal injections of cerulein(20μg/kg body weight,six consecutive injections).Following SAP induction,a drainage tube connected to a vacuum ball was placed into the lower right abdomen of the rats to build APD.Morphological changes,serum inflammatory mediators,serum and ascites high mobility group box protein 1(HMGB1),intestinal barrier function indices,apoptosis and associated proteins,and toll-like receptor 4(TLR4)signaling molecules in intestinal tissue were assessed.RESULTS APD significantly alleviated intestinal mucosal injury induced by SAP,as demonstrated by decreased pathological scores,serum levels of D-lactate,diamine oxidase and endotoxin.APD reduced intestinal inflammation and accompanying apoptosis of mucosal cells,and normalized the expression of apoptosis-associated proteins in intestinal tissues.APD significantly suppressed activation of the intestinal TLR4 signaling pathway mediated by HMGB1,thus exerting protective effects against SAP-associated intestinal injury.CONCLUSION APD improved intestinal barrier function,intestinal inflammatory response and accompanying mucosal cell apoptosis in SAP rats.The beneficial effects are potentially due to inhibition of HMGB1-mediated TLR4 signaling.
文摘Background: Existing studies have found that some inflammatory factors cause brain cell damage through the TLR4/NF-κB pathway, and that mild hypothermia has a protective effect on nerve cells. It is not clear whether the mild hypothermic brain protection is achieved through the TLR4/NF-κB pathway in microglia. Objective: To investigate the impacts of mild hypothermia on lipopolysaccharide (LPS)-mediated TLR4/NF-κB signaling pathway in microglia. Method: The cultured microglia cells in vitro were divided into the NS group and the LPS group at 33?C and 37?C, respectively;quantitative RT-PCR was performed to detect the expressions of TLR4 and NF-κB mRNA in the microglia, Western blot was used to detect the expressions of TLR4 and NF-κB protein in the microglia, and ELISA was performed to detect the levels of tumor necrosis factor α (TNF-α) and interleukin-10 (IL-10) in the culture medium. Results: Under the LPS stimulation, the mRNA and protein expressions of TLR4 and NF-κB at different time points had significant changes between the normothermia group and the mild hypothermia group, in which the expressions in the former group were firstly increased and then decreased, while those in the latter showed a continuous increasing trend (P < 0.01);and the expressions of TNF-α in all the groups presented the trend of first-increasing then-decreasing, while IL-10 exhibited one slow linear increasing trend (P Conclusions: Mild hypothermia could inhibit the mRNA and protein expressions of LPS-mediated TLR4/NF-κB signaling pathway in the microglia, and inhibit the production and release of downstream inflammatory cytokines (TNF-α and IL-10).
基金Natural Science Foundation Project of Anhui Province,No.1708085QH218。
文摘BACKGROUND Budd-Chiari syndrome(BCS)is an uncommon disorder characterized by obstruction of hepatic venous outflow.To date,the exact mechanism underlying hepatic injury derived from the hepatic venous outflow obstruction in BCS remains largely unknown.AIM To assess the role of NF-κB-mediated inflammation in BCS-induced liver injury in humans and rats.METHODS A total of 180 rats were randomly assigned into nine groups,including four BCS model groups(1,3,6 and 12 wk),four sham-operated groups(1,3,6 and 12 wk),and a control group.Lipopolysaccharide(LPS)levels in each group were detected by the Tachypleus Amebocyte Lysate assay.The mRNA and protein levels of TLR4,NF-κB,tumor necrosis factor(TNF)-α,interleukin(IL)-2 and interferon(IFN)-γwere quantified.In addition,60 patients with BCS and 30 healthy controls were enrolled,and their blood samples were analyzed.RESULTS Hepatic and plasma LPS levels were significantly increased in rats.The mRNA and protein expression levels of TLR4,NF-κB and inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in liver tissues were significantly higher in the BCS model groups compared with the other two groups.In addition,the model groups(1,3,6 and 12 wk after BCS induction)showed significant differences in the levels of LPS,TLR4,NF-κB,TNF-α,IL-2 and IFN-γ.Notably,there was a significant correlation between the LPS concentrations and mRNA and protein levels of TLR4,NF-κB and inflammatory cytokines.Importantly,it was revealed that the levels of LPS,TLR4,NF-κB and inflammatory cytokines were significantly greater in chronic BCS patients than healthy controls and acute BCS patients.CONCLUSION LPS level is markedly elevated in BCS,in turn activating the TLR4/NF-κB signaling pathway,leading to induction of inflammatory cytokines(TNF-α,IL-2 and IFN-γ)in response to BCS-induced liver injury.
