Semaphorin 7A impairs barrier function in cultured human corneal epithelial cells in a manner dependent on nuclear factor-kappa B

●AIM:To evaluate the role of semaphorin 7A(Sema7A)and its associated regulatory mechanisms in modulating the barrier function of cultured human corneal epithelial cells(HCEs).●METHODS:Barrier models of HCEs were treated with recombinant human Sema7A at concentrations of 0,125,250,or 500 ng/mL for 24,48,or 72h in vitro.Transepithelial electrical resistance(TEER)as well as Dextran-fluorescein isothiocyanate(FITC)permeability assays were conducted to assess barrier function.To quantify tight junctions(TJs)such as occludin and zonula occludens-1(ZO-1)at the mRNA level,reverse transcriptionpolymerase chain reaction(RT-PCR)analysis was performed.Immunoblotting was used to examine the activity of the nuclear factor-kappa B(NF-κB)signaling pathway and the production of TJs proteins.Immunofluorescence analyses were employed to localize the TJs.Enzyme-linked immunosorbent assay(ELISA)and RT-PCR were utilized to observe changes in interleukin(IL)-1βlevels.To investigate the role of NF-κB signaling activation and IL^(-1)βin Sema7A’s anti-barrier mechanism,we employed 0.1μmol/L IκB kinase 2(IKK2)inhibitor IV or 500 ng/mL IL^(-1)receptor(IL-1R)antagonist.●RESULTS:Treatment with Sema7A resulted in decreased TEER and increased permeability of Dextran-FITC in HCEs through down-regulating mRNA and protein levels of TJs in a time-and dose-dependent manner,as well as altering the localization of TJs.Furthermore,Sema7A stimulated the activation of inhibitor of kappa B alpha(IκBα)and expression of IL-1β.The anti-barrier function of Sema7A was significantly suppressed by treatment with IKK2 inhibitor IV or IL-1R antagonists.●CONCLUSION:Sema7A disrupts barrier function through its influence on NF-κB-mediated expression of TJ proteins,as well as the expression of IL-1β.These findings suggest that Sema7A could be a potential therapeutic target for the diseases in corneal epithelium.

Delayed hepatocarcinogenesis through antiangiogenic intervention in the nuclear factor-kappa B activation pathway in rats

BACKGROUND: The active form of nuclear factor-kappa B (NF-kappa B) is involved in the initiation, generation, and development of hepatocellular carcinoma (HCC), and is up-regulated in inflammation-associated malignancies. We investigated the dynamic expression of NF-kappa B and its influences on the occurrence of HCC through antiangiogenic (thalidomide) intervention in NF-kappa B activation. METHODS : Hepatoma models were induced with 2-fluorenylacetamide (2-FAA, 0.05%) in male Sprague-Dawley rats, and thalidomide (100 mg/kg body weight) was administered intragastrically to intervene in NF-kappa B activation. The pathological changes in the liver of sacrificed rats were assessed after hematoxylin and eosin staining. NF-kappa B mRNA was amplified by RT-nested PCR. The alterations of NF-kappa B and vascular endothelial growth factor (VEGF) expression were analyzed by enzyme-linked immunosorbent assay, immunohistochemistry, and Western blotting. RESULTS: Rat hepatocytes showed denatured, precancerous, and cancerous stages in hepatocarcinogenesis, with an increasing tendency of hepatic NF-kappa B, NF-kappa B mRNA, and VEGF expression, and their values in the HCC group were higher than those in controls (P<0.001). In the thalidomide-treated group, the morphologic changes generated only punctiform denaturation and necrosis at the early or middle stages, and nodular hyperplasia or a little atypical hyperplasia at the final stages, with the expression of NF-kappa B (chi(2)=9.93, P<0.001) and VEGF (chi(2)=8.024, P<0.001) lower than that in the 2-FAA group. CONCLUSION: NF-kappa B is overexpressed in hepatocarcinogenesis and antiangiogenic treatment down-regulates the expression of NF-kappa B and VEGF, and delays the occurrence of HCC. (Hepatobiliary Pancreat Dis Int 2010; 9: 169-174)

Urinary trypsin inhibitor attenuates hepatic ischemia-reperfusion injury by reducing nuclear factor-kappa B activation

BACKGROUND: Urinary trypsin inhibitor (UTI) inhibits the inflammatory response and protects against ischemia-reperfusion (I/R) injury. The inflammatory response is mediated by nuclear factor-kappa B (NF-kappa B) and its related target genes and products such as vascular endothelial cell adhesion molecule and CXC chemokines. We aimed to assess the roles of those mediators in a UTI-treated mouse model of hepatic I/R injury. METHODS: Treatment group 1 (UTI given 5 minutes prior to liver ischemia), treatment group 2 (UTI given 5 minutes after the anhepatic phase) and a control group were investigated. Blood and liver samples were obtained and compared at 1, 3, 6 and 24 hours after reperfusion. RESULTS: Attenuation of pathological hepatocellular damage was greater in the treatment groups than in the control group (P < 0.05). Compared with the control group, the UTI treatment groups showed significantly lower serum alanine aminotransferase and aspartate aminotransferase levels, decreased myeloperoxidase activity, and reduced NF-kappa B activation. Also downregulated was the expression of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and macrophage inflammatory protein-2 at the mRNA level. P-selectin protein and intercellular adhesion molecule-1 protein expression were also downregulated. In addition, the treatment group I showed a better protective effect against I/R injury than the treatment group 2. CONCLUSIONS: UTI reduces NF-kappa B activation and downregulates the expression of its related mediators, followed by the inhibition of neutrophil aggregation and infiltration in hepatic I/R injury. The protective role of UTI is more effective in prevention than in treatment.

Dietary saturated fatty acid and polyunsaturated fatty acid oppositely affect hepatic NOD-like receptor protein 3 inflammasome through regulating nuclear factor-kappa B activation

AIM: To investigate the effect of different dietary fatty acids on hepatic inflammasome activation.METHODS: Wild-type C57BL/6 mice were fed either a high-fat diet or polyunsaturated fatty acid (PUFA)-enriched diet. Primary hepatocytes were treated with either saturated fatty acids (SFAs) or PUFAs as well as combined with lipopolysaccharide (LPS). The expression of NOD-like receptor protein 3 (NLRP3) inflammasome, peroxisome proliferator-activated receptor-&#x003b3; and nuclear factor-kappa B (NF-&#x003ba;B) was determined by real-time PCR and Western blot. The activity of Caspase-1 and interleukine-1&#x003b2; production were measured.RESULTS: High-fat diet-induced hepatic steatosis was sufficient to induce and activate hepatic NLRP3 inflammasome. SFA palmitic acid (PA) directly activated NLRP3 inflammasome and increased sensitization to LPS-induced inflammasome activation in hepatocytes. In contrast, PUFA docosahexaenoic acid (DHA) had the potential to inhibit NLRP3 inflammasome expression in hepatocytes and partly abolished LPS-induced NLRP3 inflammasome activation. Furthermore, a high-fat diet increased but PUFA-enriched diet decreased sensitization to LPS-induced hepatic NLRP3 inflammasome activation in vivo. Moreover, PA increased but DHA decreased phosphorylated NF-&#x003ba;B p65 protein expression in hepatocytes.CONCLUSION: Hepatic NLRP3 inflammasome activation played an important role in the development of non-alcoholic fatty liver disease. Dietary SFAs and PUFAs oppositely regulated the activity of NLRP3 inflammasome through direct activation or inhibition of NF-&#x003ba;B.

Testosterone alleviates tumor necrosis factor-alpha-mediated tissue factor pathway inhibitor downregulation via suppression of nuclear factor-kappa B in endothelial cells

We have observed earlier that testosterone at physiological concentrations can stimulate tissue factor pathway inhibitor(TFPI)gene expression through the androgen receptor in endothelial cells.This study further investigated the impact of testosterone on TFPI levels in response to inflammatory cytokine tumor necrosis factor-alpha(TNF-α).Cultured human umbilical vein endothelial cells were incubated in the presence or absence of testosterone or TNF-α.TFPI protein and mRNA levels were assessed by enzyme-linked immunosorbent assay and quantitative real-time reverse transcription polymerase chain reaction.To study the cellular mechanism of testosterone’s action,nuclear factor-kappa B(NF-κB)translocation was confirmed by electrophoretic mobility shift assays.We found that after NF-κB was activated by TNF-α,TFPI protein levels declined significantly by 37.3%compared with controls(P<0.001),and the mRNA levels of TFPI also decreased greatly(P<0.001).A concentration of 30 nmol L-1 testosterone increased the secretion of TFPI compared with the TNF-α-treated group.NF-κB DNA-binding activity was significantly suppressed by testosterone(P<0.05).This suggests that physiological testosterone concentrations may exert their antithrombotic effects on TFPI expression during inflammation by downregulating NF-κB activity.

Shuanghuanglian injection downregulates nuclear factor-kappa B expression in mice with viral encephalitis

A mouse model of viral encephalitis was induced by intracranial injection of a Coxsackie virus B3 suspension. Quantitative real-time reverse transcription-PCR and western blot assay were applied to detect mRNA and protein expression of intelectin-2 and nuclear factor-kappa B in the viral encephalitis and control groups. Nuclear factor-kappa B and intelectin-2 mRNA and protein expression were significantly increased in mice with viral encephalitis. After intraperitoneal injection of Shuanghuanglian at a dose of 1.5 mg/kg for 5 successive days, intelectin-2 and nuclear factor-kappa B protein and mRNA expression were significantly decreased. To elucidate the relationship between intelectin-2 and nuclear factor-kappa B, mice with viral encephalitis were administered an intracerebral injection of 107 pfu recombinant lentivirus expressing intelectin shRNA. Both protein and mRNA levels of intelectin and nuclear factor-kappa B in brain tissue of mice were significantly decreased. Experimental findings suggest that Shuanghuanglian injection may downregulate nuclear factor-kappa B production via suppression of intelectin production, thus inhibiting inflammation associated with viral encephalitis.

Inhibitory effects of Shuanghuanglian injection on nuclear factor-kappa B expression in mice with viral encephalitis in a time-and dose-dependent manner

Previous studies have confirmed that the anti-virus effects of Shuanghuanglian injection may be associated with nuclear factor-kappa B activity. This study observed nuclear factor-kappa B expression in mice with viral encephalitis, and showed significant decreases in nuclear factor-kappa B protein and mRNA levels following Shuanghuanglian injection. The inhibitory effect was more significant with prolonged intervention duration and increased treatment dose. These findings verify that Shuanghuanglian injection plays a therapeutic role in viral encephalitis by reducing expression of nuclear factor-kappa B in a time- and dose-dependent manner.

Effects of Five Chitosan Oligosaccharides on Nuclear Factor-kappa B Signaling Pathway

The effects of five chito-oligomers, from dimer to hexamer （chitobiose, chitotriose, chitotetraose, chitopentaose, chitohexaose） separated from chitosan oligosaccharides, on nuclear factor -kappaB （NF-rd3） signaling pathway were investigated by using luciferase assay and laser scanning microscopy. The expression of NF-rd3 downstream genes （cyclin DI, TNFa and IL-6） were tested by real time PCR. We found that all five chitosan oligosaccharides increased NF-KB-dependent luciferase gene expression and NF-KB downstream genes transcription, and the most significant were chitotetraose and chitohexaose. In addition, laser scanning microscopy experiments showed that chitotetraose and chitohexaose also activated the p65 subunite of NF-kB translocating from cytoplasm to nucleus, which suggested that they were the most potent activators of NF-kB signaling pathway.

Effects of transplantation of microencapsulated rabbit sciatic nerve on nuclear factor-kappa B expression after spinal cord injury in rats

BACKGROUND： It has been reported that nuclear factor-kappa B （NF- κB）, activated after spinal cord injury in rats, plays a key role in inflammatory responses in the central nervous system. OBJECTIVE： To investigate the effects of transplantation of microencapsulated rabbit sciatic nerve on NF- κB expression and motor function after spinal cord injury in rats, and to compare the results with the transplantation of rabbit sciatic nerve alone. DESIGN, TIME AND SETTING： This completely randomized, controlled study was performed at the Department of Neurobiology, Medical College of Nanchang University between December 2007 and July 2008. MATERIALS： A rabbit anti-NF- κB P65 monoclonal antibody was made by the Santa Cruz Company, USA and a streptavidin peroxidase immunohistochemical kit was provided by the Sequoia Company, China. METHODS： Eight rabbits were used to prepare a sciatic nerve cell suspension that was divided into two parts： one stored for transplantation, and the other mixed with a 1.5% sodium alginate solution. One hundred and twenty adult Sprague Dawley rats weighing 220-250 g were randomly divided into four groups： the microencapsulated cell group （n = 36）, the non-encapsulated cell group （n = 36）, the saline group （n = 36） and the sham operation group （n = 12）. The first three groups underwent a right hemisection injury of the spinal cord at the T10 level, into which was transplanted a gelatin sponge soaked with 10 μL of a microencapsulated nerve tissue/cell suspension （microencapsulated cell group）, a tissue/cell suspension （non-encapsulated cell group） or physiological saline （saline group）. In the sham operation group the vertebrae were exposed, but the spinal cord was not injured, and no implantation was given. MAIN OUTCOME MEASURES： Pathological changes were detected using hematoxylin-eosin staining; NF- κB expression was quantified using immunohistochemical staining; motor function was assessed using the Basso, Beattie and Bresnahan （BBB） scale. RESULTS： Spinal cord injuries, such as neuronal death and inflammatory cell infiltration, were found in the microencapsulated cell group, the non-encapsulated cell group and the saline group. However, the damage in the microencapsulated cell group was milder than in the non-encapsulated cell or saline groups. NF- κB expression in the microencapsulated cell group, the non-encapsulated cell group and the saline group was increased after spinal cord injury; it reached a peak after 24 hours, gradually decreased after 3 days, and was close to normal levels after 7 days. NF- κB expression in the microencapsulated cell group was significantly lower than in the saline group and the non-encapsulated cell group （P 〈 0.05）. With time, the motor function of the animals in each group improved to a certain extent, but did not reach normal levels. There were no significant differences in BBB scores between the different groups on post-operative day 3; however, the BBB scores for the microencapsulated cell group and the non-encapsulated cell group were significantly higher than the saline group on post-operative day 7 （P 〈 0.05）. In addition, the motor function recovered better in the microencapsulated cell group than in the non-encapsulated cell group （P 〈 0.05）. CONCLUSION： The transplantation of microencapsulated rabbit sciatic nerve can inhibit NF- κB expression and inflammatory reactions and promote recovery of motor function after spinal cord injury in rats. The effects of microencapsulated cell transplantation are superior to those of transplantation of cells alone.

Effect of Ganoderma lucidum spore on expression of insulin-like growth factor-1, nuclear factor-kappa B, and neuronal apoptosis in the epileptic rat brain

BACKGROUND：It has been reported that Ganoderma lucidum spore powder, a very well known Chinese traditional medicine, can affect immunoregulation, free radical scavenging, and anti-hypoxia responses. OBJECTIVE： To investigate the effect of Ganoderma lucidum spore powder on expression of insulin-like growth factor-1 （IGF-1）, nuclear factor-κB （NF-κB） and neuronal apoptosis in rats with pentylenetetrazol （PTZ）-induced epilepsy. DESIGN, TIME AND SETTING： A cellular and molecular biology experiment with randomized controlled study design was performed at the Central Laboratory of Basic Medical College of Jiamusi University from June to August 2005. MATERIALS： Thirty healthy, adult, male, Wistar rats were selected and randomly divided into 3 groups （10 rats per group）： control, epilepsy model, and Ganoderma lucidum spore powder. A sub-eclampsia PTZ dose （35 mg/kg） was intraperitoneally injected to induce epilepsy in the latter two groups. Wild Ganoderma lucidum spore powder （30 g/L） was provided by the wild Ganoderma lucidum plant nursery at Jiamusi, China. Immunohistochemical detection and terminal deoxynucleotidyl transferase-mediate dUTP nick end-labeling （TUNEL） kits were purchased from Wuhan Boster Biological Technology Co., Ltd., China. METHODS： Ganoderma lucidum spore powder was intragastrically administered at a dose of 10.0 mL/kg, once a day for 28 days. In the epilepsy and control groups, an equivalent volume of normal saline was intragastrically administered. MAIN OUTCOME MEASURES： Immunoreactivity for IGF-1 and NF-κB/P65 were detected by immunohistochemical staining. Neuronal apoptosis was detected using TUNEL methods. RESULTS： The hippocampus and cerebral cortex of rats with PTZ-induced epilepsy exhibited a higher number of apoptotic cells at high magnification （×400）, compared with the control group. Expression of IGF-1 and NF-κB were higher in the epilepsy group, compared with the control group （P 〈 0.01）. In Ganoderma lucidum spore-treated rats, fewer apoptotic cells were observed in the hippocampus and cerebral cortex, expression of NF-κB/P65 was lower, and immunoreactivity to IGF-1 increased more distinctly, compared with the epilepsy group. In addition, seizure latency was longer on 17, 21, and 25 days post-PTZ treatment in the Ganoderma lucidum spore powder group, compared with the epilepsy group （P 〈 0.05-0.01）. CONCLUSION： Ganoderma lucidum spore powder down-regulated expression of NF-κB in brain tissues of rats with PTZ-induced epilepsy, increased immunoreactivity to IGF-1, and inhibited neuronal apoptosis. These results indicated that Ganoderma lucidum spore powder has a neuroprotective effect.

Effects of Ginsenoside Rg1 on nuclear factor-kappa B activity in beta amyloid protein-treated neural cells

BACKGROUND： Modern pharmacological studies have shown that Ginsenoside Rgl is one of the active components of ginseng that promote intelligence in the nervous system. Ginsenoside Rgl can improve memory and learning in mouse models of β-amyloid protein （Aβ）-induced dementia. OBJECTIVE： To investigate whether effects of Ginsenoside Rgl against Aβ are associated with activity of nuclear factor-kappa B （NF-κB）. DESIGN, TIME AND SETTING： The randomized performed at the DME Center, Institute of Clinica controlled, cell biological experiment was Pharmacology, Guangzhou University of Chinese Medicine, China from July 2005 to May 2006. MATERIALS： Beta-amyloid fragment 25-35 （Aβ25-35） was supplied by the Neural Biochemical Laboratory, Xuanwu Hospital, Capital Medical University, China. Ginsenoside Rgl was obtained from National Institute for the Control of Pharmaceutical and Biological Products, China. Rabbit anti-rat NF-κB p65 antibody was purchased from Santa Cruz Biotechnology, USA. METHODS： Hippocampal neurons and cortical astrocytes of neonatal Sprague Dawley rats were harvested and treated with various concentrations （0, 5, 10, 20, and 40 μmol/L） of Aβ for 6, 12, and 24 hours to establish cellular models of Alzheimer＇s disease. Cellular models were pretreated with various concentrations of Ginsenoside Rgl （1,2, 4, 8, and 16 μmol/L）. According to cell morphology and activity, the following conditions were selected： 40 μmol/L Aβ for 24 hours, as well as 2, 4, and 8 μmol/L Ginsenoside Rg1. NF-κB activity was observed using immunofluorescence and cytochemical staining. MAIN OUTCOME MEASURES： Morphology and viability of hippocampal neurons and cortical astrocytes, and activities of NF-κB were measured. RESULTS： Hippocampal neuron activity was significantly greater in the normal and 2 and 4 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.05）. Astrocyte activity was significantly greater in the normal, 1,2, 4, 8, and 16 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.05）. NF-κB activity of hippocampal neurons was significantly greater in the normal, 2, 4, and 8 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.01）. NF-κB activity of astrocytes was significantly less in the normal, 2, 4, and 8 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.01 or P 〈 0.05）. No significant difference in NF-κB activity was determined between the 2 μmol/L Ginsenoside Rgl and normal groups （P 〉 0.05）. CONCLUSION： Ginsenoside Rgl protected neural cells by upregulating NF-κB activity in neurons and downregulating NF-κB activity in astrocytes. Ginsenoside Rgl （2 μmol/L） maintained cell activity and NF-κB activity at normal levels.

Effect of Nuclear Factor-kappa B on Vascular Endothelial Growth Factor mRNA Expression of Human Pulmonary Artery Smooth Muscle Cells in Hypoxia

In order to investigate the effect of nuclear factor kappa B (NF κB) on vascular endothelial growth factor (VEGF) mRNA expression of human pulmonary artery smooth muscle cells (HPASMCs) in hypoxia, the cultured HPASMCs in vitro were stimulated with pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF κB. The NF κB p65 nuclei positive expression was detected by immunocytochemical technique. The IκBα protein expression was measured by Western blot. RT PCR was used to detect the VEGF mRNA expression of HPASMCs. The results showed that no significant change was observed in the NF κB p65 nuclei positive expression of cultured HPASMCs during 6 h-24 h in normoxia, but the levels of NF κB p65 nuclei positive expression of cultured HPASMCs were significantly increased in hypoxia groups as compared with those in all normoxia groups ( P <0.05). The IκBα protein expression of cultured HPASMCs showed no significant change during 6 h-24 h in normoxia, but significantly decreased in hypoxia as comapred with that in normoxia groups ( P <0.05). PDTC (1 to 100 μmol/L) could inhibit the VEGF mRNA expression of HPASMCs in a concentration dependent manner in hypoxia. In conclusion, NF κB can be partly translocation activated from cytoplasm into nuclei in the cultured HPASMCs under hypoxia. The inhibition of NF κB activation can decrease the VEGF mRNA expression. It is suggested that the activation of NF κB is involved in the VEGF mRNA expression of HPASMCs under hypoxia.

Treatment of COVID-19 by Controlling the Activity of the Nuclear Factor-Kappa B

Heavy infection of the virus leads to overproduction of cytokines. The overproduction of cytokine (cytokines storms) is responsible for the critical cases and deaths of COVID-19. The nuclear factor kappa-B stimulates the expression of the genes, which is responsible for cytokines storm and RNA transcription. The COVID-19 virus can be controlled by inhibition of nuclear factor kappa-B. Nuclear factor kappa-B is controlled by inhibition of hydrogen peroxide and inhibitor kappa-B kinase enzyme.

Silencing of Jumonji domain-containing 1C inhibits the osteogenic differentiation of bone marrow mesenchymal stem cells via nuclear factor-κB signaling

BACKGROUND Osteoporosis is a common metabolic bone disorder induced by an imbalance between osteoclastic activity and osteogenic activity.During osteoporosis,bone mesenchymal stem cells(BMSCs)exhibit an increased ability to differentiate into adipocytes and a decreased ability to differentiate into osteoblasts,resulting in bone loss.Jumonji domain-containing 1C(JMJD1C)has been demonstrated to suppress osteoclastogenesis.AIM To examine the effect of JMJD1C on the osteogenesis of BMSCs and the potential underlying mechanism.METHODS BMSCs were isolated from mouse bone marrow tissues.Oil Red O staining,Alizarin red staining,alkaline phosphatase staining and the expression of adipo-genic and osteogenic-associated genes were assessed to determine the differen-tiation of BMSCs.Bone marrow-derived macrophages(BMMs)were incubated with receptor activator of nuclear factor-kappaΒligand to induce osteoclast differentiation,and osteoclast differen-tiation was confirmed by tartrate-resistant acid phosphatase staining.Other related genes were measured via reverse transcription coupled to the quantitative polymerase chain reaction and western blotting.Enzyme-linked immunosorbent assays were used to measure the levels of inflammatory cytokines,including tumor necrosis factor alpha,interleukin-6 and interleukin-1 beta.RESULTS The osteogenic and adipogenic differentiation potential of BMSCs isolated from mouse bone marrow samples was evaluated.JMJD1C mRNA and protein expression was upregulated in BMSCs after osteoblast induction,while p-nuclear factor-κB(NF-κB)and inflammatory cytokines were not significantly altered.Knockdown of JMJD1C repressed osteogenic differentiation and enhanced NF-κB activation and inflammatory cytokine release in BMSCs.Moreover,JMJD1C expression decreased during BMM osteoclast differentiation.CONCLUSION The JMJD1C/NF-κB signaling pathway is potentially involved in BMSC osteogenic differentiation and may play vital roles in the pathogenesis of osteoporosis.

The Role of Toll-Like Receptors and Nuclear Factor κB p65 Protein in the Pathogenesis of Otitis Media

The role of Toll-like receptor 4 (TLR4) and nuclear factor κB p65 (NF-κB p65) proteins in the pathogenesis of otitis media is explored. In recent years, the incidence of otitis media has been rising globally, becoming a significant threat to human health. More and more studies have found that Toll-like receptor 4 (TLR4), as a member of the Toll-like receptor family, can promote the generation of inflammatory factors and is closely related to the body’s immune response and inflammatory response. Nuclear factor-κB p65 (NF-κB p65) is a nuclear transcription factor that can interact with various cytokines, growth factors, and apoptotic factors, participating in processes such as oxidative stress, apoptosis, and inflammation in the body [1]. This article elaborates on the structure, function, and signaling pathways of TLR4 and NF-κB p65 proteins in the pathogenesis of otitis media, aiming to provide more precise targets and better therapeutic efficacy for the diagnosis and treatment of otitis media. The role of inflammation in disease.

Endogenous danger signals trigger hepatic ischemia/reperfusion injury through toll-like receptor 4/nuclear factor-kappa B pathway

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.

Toll-like receptor 4/nuclear factor-kappa B signaling detected in brain after early subarachnoid hemorrhage

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.

Characteristics of hepatic nuclear-transcription factor-kappa B expression and quantitative analysis in rat hepatocarcinogenesis

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. We analyzed the expression of miclear-transcription factor-kappa B (NF-kappa B) during hepatocarcinogenesis in order to evaluate its dynamic expression and its clinical value in the development and diagnosis of HCC. METHODS: Hepatoma models were induced by oral administration of 2-acetamidoflurene (2-FAA) to male Sprague-Dawley rats. Morphological changes were observed after hematoxylin and eosin staining. The cellular distribution of NF-kappa B expression during different stages of cancer development was investigated by immunohistochemistry, and the level of NF-kappa B expression in liver tissues was quantitatively analyzed by ELISA. The gene fragments of hepatic NF-kappa B were amplified by nested-polymerase chain reaction assay. RESULTS: Hepatocytes showed vacuole-like degeneration during the early stages, then had a hyperplastic nodal appearance during the middle stages, and finally progressed to tubercles of cancerous nests with high differentiation. The NF-kappa B-positive material was buff-colored, fine particles localized in the nucleus, and the incidence of NF-kappa B-positive cells was 81.8% in degeneration, 83.3% in precancerous lesions, and 100% in cancerous tissues. All of these values were higher than those in controls (P<0.01). Hepatic NF-kappa B expression and hepatic NF-kappa B-mRNA were also higher during the course of HCC development (P<0.01). CONCLUSION: The NF-kappa B signal transduction pathway is activated during the early stages of HCC development, and its abnormal expression may be associated with the occurrence of HCC.

Resolvin D1 Protects Lipopolysaccharide-induced Acute Kidney Injury by Down-regulating Nuclear Factor-kappa B Signal and Inhibiting Apoptosis

Background： Resolvin D1 （RvD1） is a newly found anti-inflammatory bioactive compound derived from polyunsaturated fatty acids. The current study aimed to explore the protective effect of RvD1 on lipopolysaccharide （LPS）-induced acute kidney injury （AKI） and its possible mechanism. Methods： Both in vivo and in vitro studies were conducted. Male BALB/c mice were randomly divided into control group （saline）, LPS group （LPS 5 mg/kg）, RvD1 group （RvD1 5 μg/kg ＋ LPS 5 mg/kg）, and blockage group （Boc-MLP 5 gg/kg ＋ RvD1 5 gg/kg ＋ LPS 5 mg/kg）. Boc-MLP is a RvD 1 receptor blocker. The mice were intraperitoneally injected with these drugs and recorded for general condition for 48 h, while the blood and kidneys were harvested at 2, 6, 12, 24, and 48 h time points, respectively （n = 6 in each group at each time point）. Human proximal tubule epithelial cells （HK-2） were randomly divided into control group （medium only）, LPS group （LPS 5 μg/ml）, RvD1 group （RvD1 10 ng/ml ＋ LPS 5 μg/ml）, and blockage group （Boc-MLP 10 ng/ml ＋ RvD1 10 ng/ml ＋ LPS 5 μg/ml）. The cells were harvested for RNA at 2, 4, 6, 12, and 24 h time points, respectively （n = 6 in each group at each time point）. Blood creatinine was tested by using an Abbott i-STAT portable blood gas analyzer. Tumor necrosis factor-α （TNF-α level was detected by EL1SA. Kidney pathology was observed under hematoxylin and eosin （HE） staining and transmission electron microscope （TEM）. We hired immune-histological staining, Western blotting, and fluorescence quantitative polymerase chain reaction to detect the expression of RvD1 receptor ALX, nuclear factor-kappa B （NF-KB） signaling pathway as well as caspase-3. Kidney apoptosis was evaluated by TUNEL staining. Results： RvD 1 receptor ALX was detected on renal tubular epithelials. Kaplan-Meier analysis indicated that RvD 1 improved 48 h animal survival （80%） compared with LPS group （40%） and RvDI blockage group （60%）, while RvD1 also ameliorated kidney pathological injury in HE staining and TEM scan. After LPS stimulation, the mRNA expression of toll-like receptor 4, myeloid differentiation factor 88, and TNF-α in both mice kidneys and HK-2 cells were all up-regulated, while RvDI substantially inhibited the up-regulation of these genes. Western blotting showed that the phosphorylated-IKB/IKB ratio in LPS group was significantly higher than that in the control group, which was inhibited in the RvD1 group. RvD1 could inhibit the up-regulation of cleaved-caspase-3 protein stimulated by LPS, which was prohibited in RvD 1 blockage group. RvD 1 group also had a lower proportion of apoptotic nuclei in mice kidney by TUNEL staining compared with LPS group. Conclusion： In LPS-induced AKI, RvD1 could decrease TNF-α level, ameliorate kidney pathological injury, protect kidney function, and improve animal survival by down-regulating NF-KB inflammatory signal as well as inhibiting renal cell apoptosis.

Pioglitazone ameliorates nonalcoholic steatohepatitis by down-regulating hepatic nuclear factor-kappa B and cyclooxygenases-2 expression in rats

Background Pioglitazone is effective in nonalcoholic steatohepatitis （NASH）, but the mechanisms of action are not completely understood. This study was designed to investigate the effects of pioglitazone on hepatic nuclear factor-kappa B （NF-KB） and cyclooxygenases-2 （COX-2） expression in NASH rats. Methods Thirty Sprague-Dawley male rats were randomly assigned to a control group （n=10）, NASH group （n=10）, and pioglitazone treatment group （n=10）. Liver tissues were processed for histology by hematoxylin ＆ eosin and Masson stained. Serum alanine aminotransferase （ALT）, cholesterol, triglyceride, fasting blood glucose （FBG）, fasting insulin （FINS） levels and biochemical parameters of antioxidant enzyme activities, tumor necrosis factor alpha （TNF-a）, prostaglandin E2 （PGE2） levels in serum and liver were measured. The mRNA and protein expression of peroxisome proliferator-activated receptor gamma （PPARy）, NF-KB and COX-2 were determined by real-time polymerase chain reaction, Western blotting and immunohistochemistry. One-way analysis of variance （ANOVA） and Wilcoxon＇s signed-rank test was used for the statistical analysis. Results There were severe steatosis, moderate inflammatory cellular infiltration and fibrosis in NASH rats. After pioglitazone treatment, steatosis, inflammation and fibrosis were significantly improved compared with the NASH group （X2=20.40, P 〈0.001; X2=20.17, P 〈0.001; X2=13.98, P=0.002）. Serum ALT, cholesterol, triglyceride, FBG, FINS levels were significantly elevated in the NASH group （P 〈0.05）. In the NASH group, total anti-oxidation competence （T-AOC）, superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GSH-PX） and malondialdehyde （MDA） levels in serum and liver were conspicuous disordered than those parameters in the control group. Meanwhile, TNF-a and PGE2 levels in serum and liver were significantly increased compared with the control group. Immunohistochemistry showed NF-KB and COX-2 expression in liver was significantly elevated. However, PPARy level was decreased in the NASH group. Real-time PCR and Western blotting revealed mRNA and protein expression of COX-2 were increased in the NASH group compared with the control group （0.57±0.08 vs. 2.83±0.24; 0.38±0.03 vs. 1.00±0.03, P 〈0.001 and P=-0.004, respectively）. After pioglitazone intervention, all of those parameters markedly improved （P 〈0.05 or P 〈0.01）. Conclusion Down-regulating hepatic NF-KB and COX-2 expression, at least in part, is one of the possible therapeutic mechanisms of pioglitazone in NASH rats.