IL‐1β enhances the antibacterial activity of astrocytes by activation of NF‐κB

Astrocytes have important immune functions in CNS, and astrocytes stimulated by interferon‐γ were showed to have direct antimicrobial function. However whether astrocytes without the stimulation of cytokines have antibacterial function, and how this function is regulated are still largely unknown. In this study, we found that primary cultured astrocytes inhibited the growth of both gram‐negative and gram‐positive bacteria. Further more, we showed that interleukin‐1β (IL‐1β) enhanced the antibacterial effect in a dose‐dependent manner, and the antibacterial effect of astrocytes from IL‐1β receptor‐deficient mice failed to be enhanced by IL‐1β. IL‐1β stimulated IκBα degradation, NF‐κB nuclear translocation, and transactivation in astrocytes. NF‐κB inhibitors blocked NF‐κB activation and the enhanced antibacterial effect induced by IL‐1β. In addition, overexpression of dominant negative IκBα in astrocytes inhibited IκBα degradation and NF‐κB transactivation, and also inhibited the enhanced antibacterial effect induced by IL‐1β. All these data demonstrated that IL‐1β enhanced the antibacterial activity of astrocytes by activation of NF‐κB. © 2009 Wiley‐Liss, Inc.     

Nuclear factor‐κB/p65 responds to changes in the Notch signaling pathway in murine BV‐2 cells and in amoeboid microglia in postnatal rats treated with the γ‐secretase complex blocker DAPT

Microglial cells constitutively express Notch‐1 and nuclear factor‐κB/p65 (NF‐κB/p65), and both pathways modulate production of inflammatory mediators. This study sought to determine whether a functional relationship exists between them and, if so, to investigate whether they synergistically regulate common microglial cell functions. By immunofluorescence labeling, real‐time polymerase chain reaction (RT‐PCR), flow cytometry, and Western blot, BV‐2 cells exhibited Notch‐1 and NF‐κB/p65 expression, which was significantly up‐regulated in cells challenged with lipopolysaccharide (LPS). This was coupled with an increase in expression of Hes‐1, tumor necrosis factor‐α (TNF‐α), and interleukin‐1β (IL‐1β). In BV‐2 cells pretreated with N‐[N‐(3,5‐difluorophenacetyl)‐1‐alany1]‐S‐phenyglycine t‐butyl ester (DAPT), a γ‐secretase inhibitor, followed by LPS stimulation, Notch‐1 expression level was enhanced but that of all other markers was suppressed. Additionally, Hes‐1 expression and NF‐κB nuclear translocation decreased as shown by flow cytometry. Notch‐1's modulation of NF‐κB/p65 was also evidenced in amoeboid microglial cells (AMC) in vivo. In 5‐day‐old rats given intraperitoneal injections of LPS, Notch‐1, NF‐κB/p65, TNF‐α, and IL‐1β immunofluorescence in AMC was markedly enhanced. However, in rats given an intraperitoneal injection of DAPT prior to LPS, Notch‐1 labeling was augmented, but that of TNF‐α and IL‐1β was reduced. The results suggest that blocking of Notch‐1 activation with DAPT would reduce the level of its downstream end product Hes‐1 along with suppression of NF‐κB/p65 translocation, resulting in suppressed production of proinflammatory cytokines. It is concluded that Notch‐1 signaling can trans‐activate NF‐κB/p65 by amplifying NF‐κB/p65‐dependent proinflammatory functions in activated microglia. © 2010 Wiley‐Liss, Inc.     

Proinflammatory cytokine regulation of cyclic AMP‐phosphodiesterase 4 signaling in microglia in vitro and following CNS injury

Cyclic AMP suppresses immune cell activation and inflammation. The positive feedback loop of proinflammatory cytokine production and immune activation implies that cytokines may not only be regulated by cyclic AMP but also conversely regulate cyclic AMP. This study examined the effects of tumor necrosis factor (TNF)‐α and interleukin (IL)‐1β on cyclic AMP‐phosphodiesterase (PDE) signaling in microglia in vitro and after spinal cord injury (SCI) or traumatic brain injury (TBI). TNF‐α or IL‐1β stimulation produced a profound reduction (>90%) of cyclic AMP within EOC2 microglia from 30 min that then recovered after IL‐1β but remained suppressed with TNF‐α through 24 h. Cyclic AMP was also reduced in TNF‐α‐stimulated primary microglia, albeit to a lesser extent. Accompanying TNF‐α‐induced cyclic AMP reductions, but not IL‐1β, was increased cyclic AMP‐PDE activity. The role of PDE4 activity in cyclic AMP reductions was confirmed by using Rolipram. Examination of pde4 mRNA revealed an immediate, persistent increase in pde4b with TNF‐α; IL‐1β increased all pde4 mRNAs. Immunoblotting for PDE4 showed that both cytokines increased PDE4A1, but only TNF‐α increased PDE4B2. Immunocytochemistry revealed PDE4B nuclear translocation with TNF‐α but not IL‐1β. Acutely after SCI/TBI, where cyclic AMP levels are reduced, PDE4B was localized to activated OX‐42⁺ microglia; PDE4B was absent in OX‐42⁺ cells in uninjured spinal cord/cortex or inactive microglia. Immunoblotting showed PDE4B2 up‐regulation from 24 h to 1 wk post‐SCI, the peak of microglia activation. These studies show that TNF‐α and IL‐1β differentially affect cyclic AMP‐PDE signaling in microglia. Targeting PDE4B2 may be a putative therapeutic direction for reducing microglia activation in CNS injury and neurodegenerative diseases. © 2012 Wiley Periodicals, Inc.     

重组人促红细胞生成素对大鼠局灶性脑缺血再灌注损伤所致NF - κB和IκB表达的影响

目的 探讨NF - κB和IκB在重组人促红细胞生成素(r- HuEPO)对大鼠局灶性脑缺血再灌注炎性反应损伤的保护机制中的作用.方法 采用栓线法制备大鼠局灶性脑缺血再灌注模型(MCAO),应用免疫组化和Western blot分别检测缺血脑组织NF - κB和IκB的表达,IL-1β蛋白含量采用ELISA法确定.结果 与假手术组相比,脑缺血2h再灌注3h后缺血侧皮质IL- 1β含量显著升高至(86.2±25.2)pg/ml(P＜0.05),再灌注24 h IL- 1β含量达高峰(867.2±74.3)pg/ml(P＜0.01),72 h仍处于较高水平(185.5±24.4)pg/ml(P＜0.01).EPO治疗组缺血再灌注3h、6h、12 h(164.1±11.6)pg/ml和24h缺血侧皮质IL- 1β含量显著降低,与病理组相应时间点相比,分别降低了55％、33％、56％和50％(P＜0.01).脑缺血再灌注组各时相点NF - κB p65表达及活化明显增加,为Sham组的4～8倍(P＜0.01),12h表达最高(P＜0.01),是Sham组的13倍.EPO治疗组与病理组相应时相点相比,NF - κB p65表达显著减弱,EPO处理后1、3、6和12 h,NF - κB p65表达较相应的I/R组降低了33％ ～40％(P＜0.01).缺血2h再灌注1h后缺血侧皮质IκBα蛋白水平从248.6±4.2降低至195.3±4.8(P ＜0.01),6h降至最低(134.7±19.9,P＜0.01).EPO治疗组可显著增高缺血再灌注组缺血侧皮质IκBa蛋白水平(P＜0.01),各时相点分别增高了11％、34％、83％、40％、23％和20％.结论 EPO可能通过抑制NF - κB/IκB信号传导通路,减少炎性因子IL-1β的合成和分泌而达到保护脑损伤的作用.     

CD38 regulation in activated astrocytes: Implications for neuroinflammation and HIV‐1 brain infection

Reactive astrogliosis is a key pathological aspect of neuroinflammatory disorders including human immunodeficiency virus type 1 (HIV‐1)‐associated neurological disease. On the basis of previous data that showedastrocytes activated with interleukin (IL)‐1β induce neuronal injury, we analyzed global gene changes in IL‐1β‐activated human astrocytes by gene microarray. Among the up‐regulated genes, CD38, a 45‐kDa type II single chain transmembrane glycoprotein, was a top candidate, with a 17.24‐fold change that was validated by real‐time polymerase chain reaction. Key functions of CD38 include enzymatic activities and involvement in adhesion and cell signaling. Importantly, CD38⁺CD8⁺ T‐cell expression is a clinical correlate for progression of HIV‐1 infection and biological marker for immune activation. Thus, CD38 expression in HIV‐1 and/or IL‐1β‐stimulated human astrocytes and human brain tissues was analyzed. IL‐1β and HIV‐1 activation of astrocytes enhanced CD38 mRNA levels. Both CD38 immunoreactivity and adenosine 5′‐diphosphate (ADP)‐ribosyl cyclase activity were up‐regulated in IL‐1β‐activated astrocytes. CD38 knockdown using specific siRNAs significantly reduced astrocyte proinflammatory cytokine and chemokine production. However, CD38 mRNA levels were unchanged in IL‐1β knockdown conditions, suggesting that IL‐1β autocrine loop is not implicated in this process. Quantitative immunohistochemical analysis of HIV‐seropositive without encephalitis and HIV‐1 encephalitis brain tissues showed significant up‐regulation of CD38, which colocalized with glial fibrillary acidic protein–positive cells in areas of inflammation. These results suggest an important role of CD38 in the regulation of astrocyte dysfunction during the neuroinflammatory processes involved in neurodegenerative/neuroinflammatory disorders such as HIV‐1 encephalitis. © 2009 Wiley‐Liss, Inc.     

Inflammatory cytokine receptor blockade in a rodent model of mild traumatic brain injury

In rodent models of traumatic brain injury (TBI), both Interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNFα) levels increase early after injury to return later to basal levels. We have developed and characterized a rat mild fluid percussion model of TBI (mLFP injury) that results in righting reflex response times (RRRTs) that are less than those characteristic of moderate to severe LFP injury and yet increase IL‐1α/β and TNFα levels. Here we report that blockade of IL‐1α/β and TNFα binding to IL‐1R and TNFR1, respectively, reduced neuropathology in parietal cortex, hippocampus, and thalamus and improved outcome. IL‐1β binding to the type I IL‐1 receptor (IL‐1R1) can be blocked by a recombinant form of the endogenous IL‐1R antagonist IL‐1Ra (Kineret). TNFα binding to the TNF receptor (TNFR) can be blocked by the recombinant fusion protein etanercept, made up of a TNFR2 peptide fused to an Fc portion of human IgG1. There was no benefit from the combined blockades compared with individual blockades or after repeated treatments for 11 days after injury compared with one treatment at 1 hr after injury, when measured at 6 hr or 18 days, based on changes in neuropathology. There was also no further enhancement of blockade benefits after 18 days. Given that both Kineret and etanercept given singly or in combination showed similar beneficial effects and that TNFα also has a gliotransmitter role regulating AMPA receptor traffic, thus confounding effects of a TNFα blockade, we chose to focus on a single treatment with Kineret. © 2015 Wiley Periodicals, Inc.     

IL1β- and LPS-induced serotonin secretion is increased in EC cells derived from Crohn's disease

Abstract Gut mucosal enterochromaffin (EC) cells are regarded as key regulators of intestinal motility and fluid secretion via secretion of serotonin (5HT), are increased in numbers in mucosal inflammation and located in close proximity to immune cells. We examined whether interleukin (IL)1β and Escherichia coli lipopolysaccharide (LPS) induced EC cell 5HT release through Toll‐like/IL‐1 (TIL) receptor activation, nuclear factor kappa B (NFκB) and mitogen‐activated protein kinase (MAPK) phosphorylation and evaluated whether somatostatin could inhibit this phenomenon. Pure (>98%) human intestinal EC cells were isolated by fluorescent activated cell sorting from preparations of normal (n = 5) and Crohn’s colitis (n = 6) mucosa. 5HT release was measured (ELISA), and NFκB and ERK phosphorylation quantitated (ELISA) in response to IL1β and LPS. 5HT secretion was increased by both E. coli LPS (EC₅₀ = 5 ng mL^?1) and IL1β (EC₅₀ = 0.05 pmol L^?1) >2‐fold (P < 0.05) in Crohn’s EC cells compared with normal EC cells. Secretion was reversible by the TLR4 antagonist, E. coli K12 LPS (IC₅₀ = 12 ng mL^?1) and the IL1β receptor antagonist (ILRA; IC₅₀ = 3.4 ng mL^?1). IL1β caused significant (P < 0.05) NFκB and MAPK phosphorylation (40–55%). The somatostatin analogue, lanreotide inhibited IL1β‐stimulated secretion in Crohn’s (IC₅₀ = 0.61 nmol L^?1) and normal EC cells (IC₅₀ = 1.8 nmol L^?1). Interleukins (IL1β) and bacterial products (E. coli LPS) stimulated 5HT secretion from Crohn’s EC cells via TIL receptor activation (TLR4 and IL1β). Immune‐mediated alterations in EC cell secretion of 5HT may represent a component of the pathogenesis of abnormal bowel function in Crohn’s disease. Inhibition of EC cell‐mediated 5HT secretion may be an alternative therapeutic strategy in the amelioration of inflammatory bowel disease symptomatology.     

In vivo expression of proinflammatory cytokines in HIV encephalitis: an analysis of 11 autopsy cases

As the pathogenesis of AIDS dementia complex (ADC), cytokines such as TNF‐α and IL‐1β have been thought to have toxic effects on CNS cells and induce neuronal cell death. However, many of the discussions have been based on the studies done by in vitro experiments. There are only a few reports which demonstrate proinflammatory cytokines directly in vivo in HIV encephalitis (HIVE) brains, and roles of these cytokines with relation to HIV‐1 infection are not yet clarified. In the present study, we examined 11 autopsy cases of HIVE using immunohistochemistry, and explored which cell types expressed these cytokines and whether expression of cytokines was related to viral infection. IL‐1β was detected in the frontal white matter of all 11 cases where microglial nodules were observed to varying degrees, whereas TNF‐α was detected in seven cases. IL‐1β? or TNF‐α‐positive cells were almost restricted to CD68‐positive macrophages/microglia and mild expression of these cytokines by astrocytes was observed in two cases with severe HIVE. IL‐1β was detected in some HIVp24‐positive multinucleated giant cells. However, we could not detect TNF‐α expression in the HIVp24‐positive cells, which indicates that IL‐1β is induced by HIV‐1 infection. In conclusion, a macrophage/microglia lineage is the main cell type to release cytokines in HIVE, and IL‐1β expression by HIV‐1‐infected cells may be one of the important factors for induction of HIVE. In addition, many non‐infected macrophages/microglia as well as some astrocytes express IL‐1β and TNF‐α, which might contribute to pathogenesis of ADC.     

Differential contributions of microglial and neuronal IKKβ to synaptic plasticity and associative learning in alert behaving mice

Microglia are CNS resident immune cells and a rich source of neuroactive mediators, but their contribution to physiological brain processes such as synaptic plasticity, learning, and memory is not fully understood. In this study, we used mice with partial depletion of IκB kinase β, the main activating kinase in the inducible NF‐κB pathway, selectively in myeloid lineage cells (mIKKβKO) or excitatory neurons (nIKKβKO) to measure synaptic strength at hippocampal Schaffer collaterals during long‐term potentiation (LTP) and instrumental conditioning in alert behaving individuals. Resting microglial cells in mIKKβKO mice showed less Iba1‐immunoreactivity, and brain IL‐1β mRNA levels were selectively reduced compared with controls. Measurement of field excitatory postsynaptic potentials (fEPSPs) evoked by stimulation of the CA3‐CA1 synapse in mIKKβKO mice showed higher facilitation in response to paired pulses and enhanced LTP following high frequency stimulation. In contrast, nIKKβKO mice showed normal basic synaptic transmission and LTP induction but impairments in late LTP. To understand the consequences of such impairments in synaptic plasticity for learning and memory, we measured CA1 fEPSPs in behaving mice during instrumental conditioning. IKKβ was not necessary in either microglia or neurons for mice to learn lever‐pressing (appetitive behavior) to obtain food (consummatory behavior) but was required in both for modification of their hippocampus‐dependent appetitive, not consummatory behavior. Our results show that microglia, through IKKβ and therefore NF‐κB activity, regulate hippocampal synaptic plasticity and that both microglia and neurons, through IKKβ, are necessary for animals to modify hippocampus‐driven behavior during associative learning. GLIA 2015;63:549–566     

口服法舒地尔治疗EAE对巨噬细胞、T细胞及TLR/NF-B通路的作用研究

目的探讨口服盐酸法舒地尔(Fasudil)对实验性自身免疫性脑脊髓炎(experimental allergic encephalomyelitis,EAE)小鼠巨噬细胞及TLR/NF-B通路的作用。方法采用小鼠髓鞘少突胶质细胞糖蛋白35-55肽(myelin oligodendrocyte glycoprotein 35-55peptide,MOG35-55)诱导C57BL/6小鼠建立EAE模型,将EAE小鼠随机分为EAE模型组和Fasudil治疗组,免疫后第3天给予Fasudil治疗组小鼠Fasudil灌胃干预,直到免疫后第27天,EAE模型组同样处理给予等量生理盐水。光镜观察脊髓组织CD4+T细胞/CD68巨噬细胞表达的变化,Western blot法测定脊髓诱导型一氧化氮合酶(iNOS)、精氨酸酶1(Arg-1)、Toll样受体2(TLR-2)、TLR-4和磷酸化核因子B(p-NF-B)蛋白的表达,ELISA法测定培养72h脾细胞分泌细胞因子的含量。结果与EAE模型组比较,Fasudil组CD4+T细胞数和CD68巨噬细胞数明显减少(P0.01),巨噬细胞M1表型iNOS表达减少(P0.05),M2表型Arg-1表达增加(P0.01),炎性通路蛋白p-NF-B、TLR-2和TLR-4表达减少(P0.05),外周细胞炎性因子白细胞介素-6(IL-6)、IL-1β、肿瘤坏死因子α(TNF-α)、干扰素γ(IFN-γ)和IL-17分泌减少(P0.05),而IL-10分泌增加(P0.05)。结论口服Fasudil可抑制CD4+T细胞/CD68巨噬细胞的激活,促进巨噬细胞表型M1向M2转化,抑制脊髓组织中p-NF-B、TLR-2和TLR-4的表达,抑制外周免疫细胞炎性因子分泌,而增加IL-10的分泌。     

Peripheral challenge with double‐stranded RNA elicits global up‐regulation of cytokine gene expression in the brain

It is well established that mediators of peripheral inflammation are relayed to the brain and elicit sickness behavior via neuroinflammatory agents that target neuronal substrates. In the present study, we used double‐stranded RNA (dsRNA), a viral replication intermediate, to mimic the acute phase of viral infection. C57BL/6 mice were injected intraperitoneally with 12 mg/kg of synthetic dsRNA, i.e., polyinosinic‐polycytidylic acid (PIC). The treatment induced severe sickness behavior in the animals as revealed by the burrowing test performed 6 hr postinjection. PIC challenge also induced up‐regulation of mRNA for several cytokines in the brain as determined by real‐time quantitative RT‐PCR. In all brain regions, i.e., the forebrain, brainstem, and cerebellum, the gene encoding the CXCL2 chemokine featured the most robust up‐regulation over the basal level (saline‐injected animals), followed by the genes encoding the CCL2 chemokine, interferon‐β (IFNβ), interleukin‐6 (IL‐6), tumor necrosis factor‐α (TNFα), and interleukin‐1β (IL‐1β). The forebrain featured the highest extent of up‐regulation of the Ifnb gene, whereas the other genes attained the highest expression in the cerebellum. Most of the genes featured transient up‐regulation, with peaks occurring 3–6 hr after PIC challenge. The TNFα, CCL2, CXCL2, IFNβ, and IL‐1β messages remained profoundly up‐regulated even at 24 hr. The expression of genes encoding inducible and neuronal nitric oxide synthase (NOS) in the brain was not affected by the peripheral PIC challenge. However, the endothelial NOS message was initially down‐regulated and subsequently up‐regulated, indicating stimulation of cerebral vasculature. © 2008 Wiley‐Liss, Inc.     

Tumor necrosis factor‐α potentiates long‐term potentiation in the rat dentate gyrus after acute hypoxia

An inadequate supply of oxygen in the brain may lead to an inflammatory response through neuronal and glial cells that can result in neuronal damage. Tumor necrosis factor‐α (TNF‐α) is a proinflammatory cytokine that is released during acute hypoxia and can have neurotoxic or neuroprotective effects in the brain. Both TNF‐α and interleukin‐1β (IL‐1β) have been shown by a number of research groups to alter synaptic scaling and also to inhibit long‐term potentiation (LTP) in the hippocampus when induced by specific high‐frequency stimulation (HFS) protocols. This study examines the effects of TNF‐α on synaptic transmission and plasticity in hippocampal slices after acute hypoxia using two HFS protocols. Field excitatory postsynaptic potentials were elicited in the medial perforant pathway of the dentate gyrus. Exogenous TNF‐α (5 ng/ml) attenuated LTP induced by theta burst stimulation but had no effect on LTP induced by a more prolonged HFS. Pretreatment with lipopolysaccharide (100 ng/ml) or TNF‐α but not IL‐1β (4 ng/ml) prior to a 30‐min hypoxic insult resulted in a significant enhancement of LTP post hypoxia when induced by the HFS. Anti‐TNF, 3,6′‐dithiothalidomide (a TNF‐α synthesis inhibitor), and SB203580 (a p38 MAPK inhibitor) significantly reduced this effect. These results indicate an important modulatory role for elevated TNF‐α levels on LTP in the hippocampus after an acute hypoxic event. © 2015 Wiley Periodicals, Inc.     

The Correlation Between Cytokine Production by Cerebral Cortical Glial Cells and Brain Lateralization in Mice

Objectives. This study aims to explore the relationship among the levels of interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α (TNF‐α) produced by cortical glial cells, and identify any correlation between neuromodulation and brain lateralization. Material and Methods. Cortical glial cells from Balb/c neonatal mice were cultured in vitro and the effects of treating or not treating these cells from both hemispheres with lipopolysaccharide (LPS) (10 µg/mL) for 24 hours were tested. The levels of IL‐1β, IL‐6, and TNF‐α in left and right cortical glial cell cultures and the time course of any changes were compared. Rusults. The production of IL‐1β and TNF‐α had no significant difference between right and left cortex in the untreated group within 24 hours. IL‐6 was significantly higher in the right than the left cortical glial cells. In the LPS‐treated group, increased levels of IL‐1β, TNF‐α, and IL‐6 were found, particularly for IL‐6, and all were significantly increased in cortical glia cells from the right side. The time course shows that the expression of IL‐1β in right cortex and IL‐6 in both sides is time‐dependent (p < 0.05). Conclusion. Lipopolysaccharide increases cytokine production in both cerebral cortices, three cytokines have different expression time course within 72 hours, but only IL‐1β in right cortex and IL‐6 releasing is time‐dependent, and more so on the right side than the left in 24 hours. We proposed the increased immunosuppressive activity of right cortex was due to the higher expression of IL‐1β, TNF‐α, and IL‐6 in the right cortical glial cells, whereas there would be more immunoenhancement activity of the left cortex due to the lower levels of these three kinds of cytokines, this being a less pronounced effect than that on the right side. One of the reasons for the brain lateralization may be the different production of cytokines by the cortical glial cells on either side.     

促红细胞生成素对颅脑创伤后炎性反应和细胞凋亡的影响

目的 探讨重组人促红细胞生成素(rhEPO)对大鼠创伤性脑损伤后(TBI)脑组织核因子NF-κB的表达、下游炎性因子水平及皮层神经细胞凋亡的调控作用.方法 72只Wistar大鼠随机分成对照组、TBI组、TBI+rhEPO组,后两组再分为脑损伤后1 d、3 d、7 d亚组,应用EMSA法检测挫伤灶周围脑组织NF-κB结合活性、ELISA法检测炎性因子TNF-α、IL-6水平、干湿比重法检测脑组织水含量、TUNEL法检测皮层神经细胞凋亡.结果 TBI后脑组织中NF-κB结合活性、炎性因子水平持续升高;伤后脑水肿明显;TUNEL阳性细胞显著增多.给予rhEPO治疗后,脑组织NF-κB结合活性、TNF-α、IL-6水平、伤侧脑组织水肿程度及神经细胞凋亡均比TBI组降低(P＜O.01).结论 rhEPO能够抑制TBI后脑组织NF-κB的结合活性、降低下游炎性因子的表达和脑水肿程度、减少神经细胞凋亡,明显减轻继发性脑损害.

Abstract：

Objective To investigate the role of rhEPO in regulating expression of nuclear factor -kappaB (NF - κB) , proinflammatory cytokines and neural apoptosis in the injured brain following traumatic brain injury. Methods A total of 72 Wistar rats were randomly divided into control group, trauma group and rhEPO treatment group. TBI group and rhEPO group sacrificed at days 1, 3 and 7 post injury respectively. Activity of NF - κB in the brain tissues were detected by using EMSA and levels of TNF - αand IL - 6 by ELISA. The water content of the injured brain was measured by dry - wet weight method. Furthermore, apoptosis in the cortical contusion was estimated by TUNEL method. Result The result showed a persistent up - regulation of NF - κB binding activity, expression of TNF -α,IL -6 in the area surrounding the injuried brain and significant brain edema. The TUNEL positive cells significantly increased. The level of NF - κB binding activity and inflammatory factors expression, the water content of the injury brain and apoptosis can be significantly decreased by administration of rhEPO ( P ＜ 0.01). Conclusion rhEPO administration can inhibit the binding activity of the NF - κB, down - regulate the expression of the inflammatory factors, alleviate the brain edema and apoptosis and decrease the secondary brain injury after TBI.     

Activation of brain endothelium by soluble aggregates of the amyloid-β protein involves nuclear factor-κB

Cerebrovascular accumulation of amyloid-β protein (Aβ) aggregates in Alzheimer's disease (AD) is proposed to contribute to disease progression and brain inflammation as a result of Aβ-induced increases in endothelial monolayer permeability and stimulation of the endothelium for cellular adhesion and transmigration. These deficiencies facilitate the entry of serum proteins and monocyte-derived microglia into the brain. In the current study, a role for nuclear factor-κB (NF-κB) in the activation of cerebral microvascular endothelial cells by Aβ is explored.Quantitative immunocytochemistry is employed to demonstrate that Aβ(1-40) preparations containing isolated soluble aggregates elicit the most pronounced activation and nuclear translocation of NF-κB. This rapid and transient response is observed down to physiological Aβ concentrations and parallels phenotypic changes in endothelial monolayers that are selectively elicited by soluble Aβ(1-40) aggregates. While monomeric and fibrillar preparations of Aβ(1-40) also activated NF-κB, this response was less pronounced, limited to a small cell population, and not coupled with phenotypic changes. Soluble Aβ(1-40) aggregate stimulation of endothelial monolayers for adhesion and subsequent transmigration of monocytes as well as increases in permeability were abrogated by inhibition of NF-κB activation. Together, these results provide additional evidence indicating a role for soluble Aβ aggregates in the activation of the cerebral microvascular endothelium and implicate the involvement of NF-κB signaling pathways in Aβ stimulation of endothelial dysfunction associated with AD.