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.

Isoflavone Attenuates the Nuclear Transcription Factor Kappa B (NF-<i>κ</i>B) Activation on MPP⁺-Induced Apoptosis of PC12 Cells

Objective: To explore the underlying molecular mechanisms of cellular response to the challenge by 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of PC12 cells, an in vitro cell model for Parkinson’s disease, and the effect of NF-κB activation on the protection of Parkinson’s disease by Isoflavone (I). Methods: PC12 cells were used to establish the cell model of Parkinson’s disease, and are divided into five groups: control group;MPP+ group;I (Isoflavone) + MPP+ group;I group;SN-50 + MPP+ group. The content of NF-κB in PC12 cells was determined by immunocytochemistry;The viability of PC12 cells after treated with cell-permeable NF-κB inhibitor SN-50 and cell viability were measured by MTT assay;the expression levels of NF-κB p65 in cytoplasm and nuclear fractions were evaluated by western blot analysis;the mRNA expression of NF-κB p65 was analyzed by in situ hybridization (ISH). Results: Compared with the control group, the protein of NF-κB p65 both in cytoplasm and in nuclei was significantly higher than in I + MPP+ and MPP+ groups;similarly, the mRNA expression level of NF-κB p65 gene was also significantly higher;moreover, the protein expression of NF-κB p65 was much lower in I group (P + group, the protein of NF-κB p65 was significantly lower in I + MPP+ group, the mRNA expression level of NF-κB p65 gene was also significantly lower, and the protein expression level of NF-κB p65 was much lower in I + MPP+ group (P + group (P > 0.05). Conclusion: NF-κB activation is essential to MPP+-induced apoptosis in PC12 cells;but Isoflavone can inhibit the cell damage to some extent to execute its protective function, which may be involved in nigral neurodegeneration in patients with Parkinson’s disease.

Apigenin ameliorates imiquimod-induced psoriasis in C57BL/6J mice by inactivating STAT3 and NF-κB

Psoriasis is a chronic autoimmune disease featured by patches on the skin.It is caused by malfunction of immune cells and keratinocytes with inflammation as one of its key features.Apigenin(API)is a natural flavonoid with anti-inflammatory and immunoregulatory properties.Therefore,we speculated that API can ameliorate psoriasis,and determined its effect on the development of psoriasis by using imiquimod(IMQ)-induced psoriasis mouse model.Our results showed that API attenuated IMQ-induced phenotypic changes,such as erythema,scaling and epidermal thickening,and improved splenic hyperplasia.Abnormal differentiation of immune cells was restored in API-treated mice.Mechanistically,we revealed that API is a key regulator of signal transducer activator of transcription 3(STAT3).API regulated immune responses by reducing interleukin-23(IL-23)/STAT3/IL-17A axis.Moreover,it suppressed IMQ-caused cell hyperproliferation by inactivating STAT3 through regulation of extracellular signal-regulated kinase 1/2 and nuclear factor-κB(NF-κB)pathway.Furthermore,API reduced expression of inflammatory cytokines through inactivation of NF-κB.Taken together,our study demonstrates that API can ameliorate psoriasis and may be considered as a strategy for psoriasis treatment.

Glycine Attenuates Myocardial Fibrosis in Myocardial Infarction in Rats Partly through Modulating Signal Transducer and Activator of Transcription 3/Nuclear Factor-κB/Transforming Growth Factor-β axis

Objective: Inflammation and fibrosis are strongly associated with each other. Glycine is present in various traditional Chinese medicines and exhibits anti-inflammatory activity. However, the effects of glycine on myocardial fibrosis(MF) in rats with myocardial infarction(MI) have not been reported. The purpose of this study is to investigate the effects of glycine therapy on MF and comprehend its underlying mechanisms. Materials and Methods: Left anterior descending artery ligation-induced MI in Sprague Dawley rats was leveraged to assess the therapeutic effects of Glycine. Rats received either normal saline or glycine(0.5 mg/g bodyweight) for 7 days. Results: Glycine upregulated cardiac ejection fraction and fractional shortening to improve cardiac function, as evaluated by echocardiography. Histological and immunohistochemical analyses demonstrated that glycine could decrease inflammatory cell infiltration and alleviate collagen deposition. Western blotting revealed that nuclear factor-κB(NF-κB)-mediated inflammatory signaling was also downregulated by glycine treatment. The expression of signal transducer and activator of transcription 3(STAT3), tumor necrosis factor-α, and transforming growth factor-β(TGF-β) was decreased significantly in the glycine-treated group compared to the model group. Thus, glycine plays a protective role against myocardial ischemia and subsequent MF. Conclusion: The protective effects of glycine were achieved partly through STAT3/NF-κB/TGF-β signaling pathway.

Effects of ω-3 fatty acids on toll-like receptor 4 and nuclear factor-κB p56 in lungs of rats with severe acute pancreatitis

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.

Clinical significance of SQSTM1/P62 and nuclear factor-κB expression in pancreatic carcinoma

BACKGROUND Overexpression of SQSTM1(sequestosome 1,P62)and nuclear factor-κB(NF-κB)plays an important role in the invasion and metastasis of a variety of malignant tumors.AIM To explore the expression of P62 and NF-κB in pancreatic cancer and their relationship with clinicopathological features.METHODS The expression levels of P62 and NF-κB were analyzed by immunohistochemistry with a tissue chip containing 40 cases of human pancreatic carcinoma.Then we analyzed the correlation among P62 expression,phospho-P65 expression,and clinicopathological features of pancreatic carcinoma samples.RESULTS P62 expression was mainly observed in the cytoplasm of pancreatic carcinoma cells.Phosphorylated P65(phospho-P65)was mainly expressed in the nucleus and cytoplasm of pancreatic carcinoma cells.There was a significant difference in P62 expression among T stages.And a significant difference in phosphor-P65 expression among pathology types was noted.In the cases with strongly positive P62 expression,significant differences were found in age.And there were significant differences in T stage and tumor-node-metastasis stage in the cases with strongly positive phosphor-P65 expression.CONCLUSION In pancreatic carcinoma,P62 expression is significantly correlated with T stage.It may be a valuable malignant indicator for human pancreatic carcinoma.

Effect of NF-κB p65 antisense oligodeoxynucleotide on transdifferentiation of normal human lens epithelial cells induced by transforming growth factor-β2

AIM：To study the inhibition of nuclear factor kappa-B p65（NF-κB p65）antisense oligodeoxynucleotide（ASODN）on transdifferentiation of normal human lens epithelial cells induced by transforming growth factor-β2（TGF-β2）.·M ETHODS：NF-κBp65ASODNand NF-κBp65missense oligodeoxynucleotide（MSODN）were designed and synthesized.Human lens epithelial cell line（HLE B-3）cells were prepared for study and divided into 7 groups.Control group was HLE B-3 cells cultured in dulbecco’s modified eagle medium（DMEM）.T1,T2,and T3 group were HLE B-3 cells cultured in DMEM with 10 ng/m L TGF-β2 for 6h,12h,24h respectively.A＋T group was HLE B-3 cells cultured with 10 ng/m L TGF-β2for 24h after transfected by NF-κB p65 ASODN for 24h.M＋T group was HLE B-3 cells cultured with 10 ng/m L TGF-β2 for 24h after transfected by NF-κB p65 MSODN for 24h.The negative control group was HLE B-3 cells cultured with 10 ng/m L TGF-β2 for 24h after cultured with transfer agent（Hi Per Fect）for 24h.Cell morphology was observed at different time points using an inverted microscope.The expression of NF-κB p65 m RNA was detected with reverse transcription-polymerase chain reaction（RT-PCR）,and the expression ofα-smooth muscle actin（α-SMA）protein was assayed with ELISA.·RESULTS：With the TGF-β2 stimulation prolongation,the expression of NF-κB p65 m RNA and a-SMA protein increased in T1,T2,T3 groups compared with the control group,and the difference was statistically significant（〈0.05）.NF-κB p65 ASODN lowered the expression of NF-κB p65 m RNA andα-SMA protein induced by TGF-β2.NF-κB p65 MSODN and Hi Per Fect did not lower the expression of NF-κB p65 m RNA andα-SMA protein induced by TGF-β2.The difference between control group and A＋T group was not statistically significant（〉0.05）,but the difference among A＋T group and other groups was statistically significant（〈0.05）.·CONCLUSION：NF-κB p65 ASODN could lower the expression of NF-κB p65 m RNA andα-SMA protein induced by TGF-β2,and antagonized TGF-β2-induced transdifferentiation of HLE B-3.NF-κB p65ASODN could be used as a new biological therapeutic target of posterior capsular opacification.

Nuclear Factor kappa B p65 Expression in Mouse Cochlea

Nuclear factor kappa B(NF-κB) is one of the best-characterized transcription factors playing important roles in many cellular responses to a large variety of stimuli,including inflammatory cytokines, phorbol esters, growth factors, and bacterial and viral products. The aim of this study is to demonstrate NF-κB expression in the mouse cochlea and its enhancement in response to lipopolysaccharides(LPS) and kanamycin(KA) treatment. Methods KA treatment consisted of subcutaneous KA injections at 700 mg/kg twice a day with an eight-hour interval between the two injections for 3 or 7 days. For animals in the LPS treatment group, a single dose of 0.3 mg LPS dissolved in 0.2 ml sterile saline were injected into both bullae through the tympanic membrane and kept there for 3 hours. Animals in the control group received subcutaneous saline injection for 7 days. Following immmunohistochemichal processing with rabbit polyclonal anti-NF-κB p65 antibodies, cryosections of the cochlea were examined for expression of NF-κB p65 in various structures in the cochlea. Results NF-κB p65 expression, identified by presence of brown reaction products characteristic of DAB immunohistochemistry, was visible in the spiral ligament, spiral prominence, tectorial membrane(TM), spiral ganglion and nerve fibers. Relatively weak NF-κB p65 expression was also visualized in the organ of Corti. Within the organ of Corti, the inner hair cells(IHC), outer hair cells(OHC), inner pillar cells(IP), outer pillar cells (OP), Deiter’s cells(DC), and Boettcher’s cells exhibited stronger staining than the inner sulcus cells, Hensen’s cells(HC) and Claudius’cells. No NF-κB p65 expression was seen in the nucleus of the IHC and OHC. NF-κB p65 expression was increased in animals exposed to LPS or KA, demonstrating significant differences in the staining between control animals and LPS/KA-treated animals. NF-κB p65 expression was not significantly different between LPS treated and KA treated animals or between 3 and 7 days in KA-treated animals. Conclusion LPS and KA exposure increases expression of NF-κB p65 in the mouse cochlea.

Suppressing high mobility group box-1 release alleviates morphine tolerance via the adenosine5'-monophosphate-activated protein kinase/heme oxygenase-1 pathway

Opioids,such as morphine,are the most potent drugs used to treat pain.Long-term use results in high tolerance to morphine.High mobility group box-1(HMGB1) has been shown to participate in neuropathic or inflammatory pain,but its role in morphine tolerance is unclear.In this study,we established rat and mouse models of morphine tolerance by intrathecal injection of morphine for 7 consecutive days.We found that morphine induced rat spinal cord neurons to release a large amount of HMGB1.HMGB1 regulated nuclear factor κB p65 phosphorylation and interleukin-1β production by increasing Toll-like receptor 4receptor expression in microglia,thereby inducing morphine tolerance.Glycyrrhizin,an HMGB1 inhibito r,markedly attenuated chronic morphine tole rance in the mouse model.Finally,compound C(adenosine 5’-monophosphate-activated protein kinase inhibitor) and zinc protoporphyrin(heme oxygenase-1 inhibitor)alleviated the morphine-induced release of HMGB1 and reduced nuclear factor κB p65 phosphorylation and interleukin-1β production in a mouse model of morphine tolerance and an SH-SY5Y cell model of morphine tole rance,and alleviated morphine tolerance in the mouse model.These findings suggest that morphine induces HMGB1 release via the adenosine 5’-monophosphate-activated protein kinase/heme oxygenase-1 signaling pathway,and that inhibiting this signaling pathway can effectively reduce morphine tole rance.

Blocking NF-kB nuclear translocation leads to p53-related autophagy activation and cell apoptosis

AIM: To investigate the anti-tumor effects of nuclear factor-κB (NF-κB) inhibitor SN50 and related mechanisms of SGC7901 human gastric carcinoma cells. METHODS: MTT assay was used to determine the cytotoxic effects of SN50 in gastric cancer cell line SGC7901. Hoechst 33258 staining was used to detect apoptosis morphological changes after SN50 treatment. Activation of autophagy was monitored with monodansylcadaverine (MDC) staining after SN50 treatment.Immunofluorescence staining was used to detect the expression of light chain 3 (LC3). Mitochondrial membrane potential was measured using the fluorescent probe JC-1. Western blotting analysis were used to determine the expression of proteins involved in apoptosis and autophagy including p53, p53 upregulated modulator of apoptosis (PUMA), damage-regulated autophagy modulator (DRAM), LC3 and Beclin 1. We detected the effects of p53-mediated autophagy activation on the apoptosis of SGC7901 cells with the p53 inhibitor pifithrin-α. RESULTS: The viability of SGC7901 cells was inhibited after SN50 treatment. Inductions in the expression of apoptotic protein p53 and PUMA as well as autophagic protein DRAM, LC3 and Beclin 1 were detected with Western blotting analysis. SN50-treated cells exhibited punctuate microtubule-associated protein 1 LC3 in immunoreactivity and MDC-labeled vesicles increased after treatment of SN50 by MDC staining. Collapse of mitochondrial membrane potential Δψ were detected for 6 to 24 h after SN50 treatment. SN50-induced increases in PUMA, DRAM, LC3 and Beclin 1 and cell death were blocked by the p53 specific inhibitor pifithrin-α. CONCLUSION: The anti-tumor activity of NF-κB inhibitors is associated with p53-mediated activation of autophagy.

Role of nuclear factor kappa B in central nervous system regeneration

Activation of nuclear factor kappa B （NF-κB） is a hallmark of various central nervous system （CNS） pathologies. Neuron-specific inhibition of its transcriptional activator subunit RelA, also referred to as p65, promotes neuronal survival under a range of conditions, i.e., for ischemic or excitotoxic insults. In macro- and microglial cells, post-lesional activation of NF-κB triggers a growth-permissive program which contributes to neural tissue inflammation, scar formation, and the expression of axonal growth inhibitors. Intriguingly, inhibition of such inducible NF-~B in the neuro-glial compartment, i.e., by genetic ablation of RelA or overexpression of a trans- dominant negative mutant of its upstream regulator IκBa, significantly enhances functional recovery and promotes axonal regeneration in the mature CNS. By contrast, depletion of the NF-κB subunit p50, which lacks transcriptional activator function and acts as a transcriptional repressor on its own, causes precocious neuronal loss and exacerbates axonal degeneration in the lesioned brain. Collectively, the data imply that NF-κB orchestrates a multicellular pro- gram in which κB-dependent gene expression establishes a growth-repulsive terrain within the post-lesioned brain that limits structural regeneration of neuronal circuits. Considering these subunit-specific functions, interference with the NF-κB pathway might hold clinical potentials to improve functional restoration following traumatic CNS injury.

Oxymatrine Improves TNBS-induced Colitis in Rats by Inhibiting the Expression of NF-κB p65

Inflammatory bowel disease is thought to be regulated by the balance between Th1 and Th2 cytokines secreted by T cells, and NF-κB p65 also plays a predominant role in the intestinal inflammation. We evaluated the potency of oxymatrine, one of active components of Sophora Root, in inhibiting the immune responses and inflammation in 2,4,6-trinitrobenzene sulfonic acid （TNBS）-induced colitis. The inflammation was markedly ameliorated in the oxymatrine-treated rats. The level of IL-2 was increased and that of IL-10 was decreased in colon tissue in the rat model, which was reversed by the treatment of oxymatrine. Moreover, the elevated expression of NF-κB p65 in colon tissue in the model was also improved by oxymatrine treatment. Our results suggest that oxymatrine might be beneficial for the abnormal immune responses and inflammation by regulating the unbalance of Th1 and Th2 cytokines secretion and inhibiting the expression of NF-κB p65 in colon tissue.

桥本甲状腺炎合并甲状腺乳头状癌患者中Toll样受体3和核转录因子-κB的表达及相关性分析

目的分析桥本甲状腺炎(Hashimoto thyroiditis,HT)合并甲状腺乳头状癌(PTC)患者Toll样受体3(toll-like receptor 3,TLR3)和核转录因子-κB(nuclear transcription factor-κB,NF-κB)表达及相关性。方法收取邯郸市中心医院2020年3月~2022年3月收治的130例行手术切除的甲状腺标本,其中正常甲状腺组织标本43例,HT标本47例,HT合并PTC标本40例,分析TLR3和NF-κB在正常甲状腺组织、HT组、HT合并PTC组中的表达,分析HT合并PTC组中TLR3和NF-κB表达与临床病理参数关系,Pearson相关性分析TLR3和NF-κB的关系。结果TLR3在正常甲状腺组织、HT组、HT合并PTC组中的阳性表达率分别为0(0/43)、80.85%(38/47)、90.00%(36/40);NF-κB在以上三组中的阳性表达率分别为0(0/43)、68.09%(32/47)、85.00%(34/40)。TLR3和NF-κB在HT组、HT合并PTC组中的阳性表达率均高于正常甲状腺组织(P<0.05),TLR3和NF-κB表达与性别、年龄、HT合并PTC病理学特征、病灶类型、淋巴结转移、甲状腺包膜侵犯差异比较均无统计学意义(P均>0.05)。TLR3和NF-κB呈显著正相关(r=0.589,P<0.05)。结论TLR3和NF-κB在HT合并PTC组织中的阳性率高于正常甲状腺组织,且二者表达呈正相关。

Curcumin suppresses gastric NF-κB activation and macromolecular leakage in Helicobacter pylori-infected rats

AIM:To investigate whether curcumin could attenuate nuclear factor(NF)-κB p65 expression and macromolecular leakage in the gastric mucosa of Helicobacter pylori(H.pylori)-infected rats.METHODS:Twenty-five male Sprague-Dawley rats were equally divided into five groups:control rats(Control),control rats supplemented with 600 mg/kg curcumin,H.pylori-infected rats(Hp),H.pylori-infected rats supplemented with 200 mg/kg curcumin(Hp + curIn H.pylori-infected groups,rats were inoculated with H.pylori suspension twice a day at an interval of 4 h for 3 d.Two weeks later,200 or 600 mg/kg curcumin was given once daily to curcuminsupplemented groups for 7 d.On the day of the experiment,macromolecular leakage in gastric mucosa was examined by intravital fluorescence microscopy.The stomach tissue was removed to examine NF-κB p65 expression in gastric epithelial cells by immunohistochemistry.RESULTS:The expression of NF-κB p65 in gastric epithelial cells and the macromolecular leakage from gastric mucosal microcirculation significantly increased in the Hp group compared with the Control group.The percentages of NF-κB p65 immunoreactive cells in Control and Hp groups were 10.72% ± 2.10% vs 16.02% ± 2.98%,P = 0.004,respectively.The percentages of macromolecular leakage in Control and Hp groups were 10.69% ± 1.43% vs 15.41% ± 2.83%,P = 0.001,respectively.Curcumin supplementation in Hp + cur-CONCLUSION:H.pylori-induced gastric inflammation in rats is associated with increased NF-κB activation and macromolecular leakage which can be reduced by curcumin supplementation.

Role of moxibustion in inflammatory responses during treatment of rat ulcerative colitis

AIM: To investigate the efficacy of moxibustion in ulcerative colitis (UC) rats from morphological, immunological and molecular biological perspectives. METHODS: Thirty-two Sprague-Dawley rats were randomly assigned to a blank control group (normal rats, n = 6) and a model replication (MR) group (UC rats, n = 26). A UC model was established by 2,4,6-trinitrobenzenesulfonic acid/dextran sulfate sodium enema. Rats in the MR group were further randomly assigned to a 9-min moxibustion (9M) group (9 moxa-cone, n = 6), 6-min moxibustion (6M) group (6 moxa-cone, n = 6), 3-min moxibustion (3M) group (3 moxa-cone, n = 6), and a waiting list control (WLC) group (no moxibustion treatment, n = 6). Rats in the moxibustion treatment group were treated in 14 sessions over 28 d. Disease activity, local tissue morphology, serum level of interleukin (IL)-8 and IL-10, and expression of Toll-like receptor (TLR)9 as well as nuclear factor (NF)-kappa B p65 in colonic tissue were determined by disease activity index (DAI), hematoxylin and eosin staining, electron microscopy, enzyme-linked immunosorbent assay and Western blotting, respectively. RESULTS: DAI was lowest in the 9M group and highest in the WLC group. The differences in DAI between the moxibustion treatment (3M, 6M, 9M) and no treatment groups were significant for all one-to-one comparisons (0.60 +/- 0.54 vs 1.20 +/- 0.44, 0.60 +/- 0.54 vs 1.80 +/- 0.45, 0.60 +/- 0.54 vs 3.0 +/- 0.45, respectively, P < 0.05). Light and electron microscopy showed that the neatness of the glandular arrangement in colonic mucosal epithelia gradually increased in the WLC, 3M, 6M to 9M groups. IL-8 level successively decreased while IL-10 level increased from the WLC to 3M, 6M and 9M groups. The differences among these groups were significant for all comparisons (105.46 +/- 8.75 vs 76.61 +/- 3.58, 105.46 +/- 8.75 vs 69.78 +/- 1.87, 105.46 +/- 8.75 vs 67.41 +/- 1.84, respectively, P < 0.01 for IL-8; and 30.83 +/- 1.29 vs 75.64 +/- 1.90, 30.83 +/- 1.29 vs 80.90 +/- 3.16, 30.83 +/- 1.29 vs 83.46 +/- 2.37, respectively, P < 0.01 for IL-10), except comparison of 6M vs 9M. Expression of TLR9 and NF-kappa B p65 decreased in order: highest in the WLC group and lowest in the 9M group. In addition, the differences among the WLC, 3M, 6M and 9M groups were significant for all comparisons (0.492 +/- 0.026 vs 0.380 +/- 0.022, 0.492 +/- 0.026 vs 0.355 +/- 0.005, 0.492 +/- 0.026 vs 0.327 +/- 0.015, respectively, P < 0.05 for TLR9; and 0.436 +/- 0.041 vs 0.326 +/- 0.022, 0.436 +/- 0.041 vs 0.293 +/- 0.006, 0.436 +/- 0.041 vs 0.265 +/- 0.017, respectively, P < 0.05 for NF-kappa B p65). CONCLUSION: Moxibustion repairs damaged colonic mucosa, suppresses serum IL-8, activates serum IL-10 level, and decreases expression of TLR-9 and NF-kappa B p65 in UC rats. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.

Microglial cathepsin B as a key driver of inflammatory brain diseases and brain aging

Interleukin-1βis a potent proinflammatory cytokine that plays a key role in the pathogenesis of the brain aging and diverse range of neurological diseases including Alzheimer’s disease,Parkinson’s disease,stroke and persistent pain.Activated microglia are the main cellular source of interleukin-1βin the brain.Cathepsin B is associated with the production and secretion of interleukin-1βthrough pyrin domain-containing protein 3 inflammasome-independent processing of procaspase-3 in the phagolysosomes.The leakage of cathepsin B from the endosomal-lysosomal system during aging is associated with the proteolytic degradation of mitochondrial transcription factor A,which can stabilize mitochondrial DNA.Therefore,microglial cathepsin B could function as a major driver for inflammatory brain diseases and brain aging.Orally active and blood-brain barrier-permeable specific inhibitors for cathepsin B can be potentially effective new pharmaceutical interventions against inflammatory brain diseases and brain aging.

Role of Δ133p53 isoform in NF-κB inhibitor PDTC-mediated growth inhibition of MKN45 gastric cancer cells

AIM To investigate the role of Δ133p53 isoform in nuclear factor-κB(NF-κB) inhibitor pyrrolidine dithiocarbamate(PDTC)-mediated growth inhibition of MKN45 gastric cancer cells.METHODS The growth rate of MKN45 cells after treatment with different concentrations of only PDTC or PTDC in combination with cisplatin was detected by the CCK-8 assay. m RNA expression levels of Δ133p53, p53β, and the NF-κB p65 subunit and p65 protein levels were detected by reverse transcription-polymerase chain reaction(RT-PCR) and immunofluorescence, respectively. Growth of MKN45 cells was significantly inhibited by PDTC alone in a dose-dependent manner(P < 0.01). Moreover, the inhibitory effect of cisplatin was remarkably enhanced in a dose-dependent manner by co-treatment with PDTC(P < 0.01).RESULTS RT-PCR analysis revealed that m RNA expression of p65 was curbed significantly in a dose-dependent manner by treatment with only PDTC(P < 0.01), and this suppressive effect was further enhanced when co-treated with cisplatin(P < 0.01). With respect to the other p53 isoforms, m RNA level of Δ133p53 was significantly reduced in a dose-dependent manner by treatment with only PDTC or PTDC in combination with cisplatin(P < 0.01), whereas p53β m RNA expression was not altered by PDTC treatment(P > 0.05). A similar tendency of change in p65 protein expression, as observed for the corresponding m RNA, was detected by immunofluorescence analysis(P < 0.01). Pearson correlation analysis demonstrated that Δ133p53 and p65 m RNA expression levels were positively related, while no significant relationship was observed between those of p65 and p53β(r = 0.076, P > 0.01).CONCLUSIONΔ133p53 isoform(not p53β) is required in PDTCinduced inhibition of MKN45 gastric cancer cells, indicating that disturbance in the cross-talk between p53 and NF-κB pathways is a promising target in pharmaceutical research for the development of treatment strategies for gastric cancer.

Sodium butyrate protects against toxin-induced acute liver failure in rats

BACKGROUND: Acute liver failure(ALF) is a serious clinical syndrome with high mortality. Sodium butyrate has been shown to alleviate organ injury in a wide variety of preclinical models of critical diseases. The aim of this study was to investigate the protective effect of sodium butyrate on ALF in rats.METHODS: All rats were randomly divided into control,model and sodium butyrate treatment groups. Except the control group, the rats were induced ALF animal model by subcutaneous injection of human serum albumin+D- galactosamine+lipopolysaccharide. After induction of ALF,the rats in the treatment group received sodium butyrate(500mg/kg) at 12-hour or 24-hour time point. Fourty-eight hours after ALF induction, the animals were sacrificed and samples were harvested. Serum endotoxin, high mobility group box-1(HMGB1), liver function parameters, tumor necrosis factoralpha(TNF-α) and interferon-gamma(IFN-γ) were measured.The expression of HMGB1 and nuclear factor-kappa B(NF-κB)p65 protein in liver tissue was detected by Western blotting. The histological changes of liver and intestine were examined. The survival duration was also observed.RESULTS: Serum endotoxin, alanine aminotransferase, HMGB1,TNF-α and IFN-γ were significantly increased and the liver histology showed more severe histopathological injury in the model group compared with the control group(P<0.05).Compared to the model group, sodium butyrate treatment significantly improved the histopathological changes in the liver and intestine, reduced serum endotoxin and inflammatory cytokines, suppressed HMGB1 and NF-кB p65 proteins in liver tissue, and prolonged the survival duration regardless of treatment at 12 hours or 24 hours after induction of ALF(P<0.05).CONCLUSIONS: Sodium butyrate protected the liver from toxin-induced ALF in rats. The mechanisms may be due to direct hepatoprotection and decreased intestinal permeability.

Effects of IκBα and its mutants on NF-κB and p53 signaling pathways

AIM： To study the effects of IκBα and its mutants （IκBαM, IκBα3N, IκBαM44C） on NF-κB, p53 and their downstream target genes. The relationship of NF-κB, p53, and IκBα was further discussed. METHODS： pECFP-IκBα, pECFP-IκBαM （amino acides 1-317, Ser32, 36A）, pECFP-IκBα243N （amino acides 1-243）, pECFP-IκBα244C （amino acides 24±317）, pEYFP-p65 and pp53-DsRed were constructed and transfected to ASTC-α-1 cells. Cells were transfected with pECFP-Cl as a control. 30 h after the transfection, location patterns of NF-κB, p53 and IκBα（IκBαM, IκBα243N, IκBα224C） were observed by a laser scanning microscope （LSM510/ConfoCor2, Zeiss）. RNA extraction and reverse transcription were performed in cells transfected or co-transfected with different plasmids. Effects of IκBα and its mutants on the transprition level of NF-κB, NF-κB downstream target gene TNF-α, p53 and p53 downstream target gene Bax were observed by real time QT-PCR. In all experiments β-actin was reference. Results are expressed as the target/reference ratio of the sample divided by the target/reference ratio of the control. Different transfected cells were incubated with CCK-8 for 2 h in the incubator. Then the absorbance at 450 nm was measured by using a microplate reader. RESULTS： Cells that were transfected with p53- DsRed revealed a predominant nuclear localization. YFP-p65 mainly existed in the cytoplasm. Cells were transfected with CFP-IκBα, CFP-IκBαM, and CFP-IκBα243N respectively and revealed a predominant cytosolic localization. However, cells transfected of CFP-IκBα244C revealed a predominant nuclear localization. The rnRNA levels of p65, TNF-α, p53 and Bax in CFP-IκBα transfected cells did not change significantly, while in YFP-p65/CFP-IκBα co-transfected cells, IκBα decreased the transcription of p65 downstream gene TNF-α （2.24 ± 0.503） compared with the YFP-p65/ CFP-C1 co-transfected cells （5.08 ± 0.891） （P 〈 0.05）. Phosphorylation defective IκBα （IκBαM） decreased the transcription levels of all the four genes compared with the control （P 〈 0.05）. The N terminus of IκBα（IκBα243N） increased the transcription of NF-κB （1.84 ± 0.176） and TNF-α （1.51 ± 0.203） a little bit. However, the C terminus of IκBα（IκBα244C） increased the transcription of NF-κB, TNF-α, p53 and Bax significantly （8.29 ± 1.662, 14.16 ± 2.121, 10.2 ± 0.621, 3.72 ± 0.346） （P 〈 0.05）. The CCK-8 experiment also showed that IκBα244C and p53 synergistically mediate apoptosis. CONCLUSIONS： IκBα and its mutants （IκBαM, IκBα243N, IκBαM244C） have different effects on NF- KB and p53 signaling pathways, according to their different structures. IκBαbounds with NF-KB and p53 in cytoplasm steadily, and inhibits both of the two signaling pathways, p53 and IκBα244C may be co-factor in inducing apoptosis. The C terminal of IκBαnhanced cell death, which suggests that it may be a pro-apoptotic protein existed in cells.

Protective effect of Jiaweibugan decoction against diabetic peripheral neuropathy

Oxygen free radical damage is regarded as a direct or indirect common pathway associated with diabetic neuropathy and is the main cause of complications in peripheral neuropathies. We speculate that Jiaweibugan decoction has a significant effect in treating diabetic peripheral neuropathy through an anti-oxidative stress pathway. In this study, a diabetic rat model was established by intraperitoneal injection of streptozotocin. Rats were treated with Jiaweibugan decoction via intragastric administration. The levels of malondialdehyde and glutathione, which are indirect indexes of oxidative stress, in serum were determined using a colorimetric method. The expression levels of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase, which are oxidative stress associated factors, in the dorsal root ganglion of spinal $4-6 segments were evaluated by reverse-transcriptase polymerase chain reaction and immunohistochemistry. Results showed that, Jiaweibugan decoction significantly ameliorated motor nerve conduction velocity in diabetic rats, effectively decreased malondialdehyde levels in serum and the expression of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase mRNA in the dorsa root ganglion, and increased glutathione levels in serum. Therefore, our experimental findings indicate that Jiaweibugan decoction plays an anti-oxidative stress role in the diabetic peripheral neuropathy process, which has a protective effect on peripheral nerve injury.