The expanding interleukin-1 family and its receptors: do alternative IL-1 receptor/signaling pathways exist in the brain?

Interleukin-1 (IL-1) has been implicated in neuroimmune responses and has pleiotropic actions in the brain. Compelling evidence has shown that IL-1 is a major mediator of inflammation and the progression of cell death in response to brain injury and cerebral ischemia. Its expression is strongly increased in these pathological conditions, and central administration of exogenous IL-1 significantly exacerbates ischemic brain damage. In contrast, inhibiting IL-1 actions (by intracerebroventricular [icv] injection of IL-1ra, neutralizing antibody to IL-1 or caspase-1 inhibitor) significantly reduces ischemic brain damage. IL-1 acts by binding to the IL-1 type-1 receptor (IL-1RI), which is to date, the only known functional receptor for IL-1. However, our recent investigations suggest that IL-1 can act independently of IL-1RI, raising the possibility that additional, as yet undiscovered, receptor(s) for IL-1 exist in the brain. The recent characterization of putative, new IL-1 ligands and new IL-1 receptor-related molecules leads to the hypothesis that there might be alternative IL-1 signaling pathway(s) in the central nervous system (CNS).     

Phloretin as an Antagonist of Prostaglandin F2α Receptor in Cultured Rat Astrocytes

Abstract: The effect of phloretin on prostaglandin (PG) F_2α-induced phosphoinositide hydrolysis and elevation of intracellular Ca²⁺ concentration was examined in cultured rat astrocytes. Phloretin inhibited PGF_2α (1 μ M )-induced phosphoinositide hydrolysis in a concentration-dependent manner with an IC₅₀ value of 16 μ M . The inhibitory action of phloretin was specific for PGs. The addition of increasing concentrations of phloretin caused progressive shifts of the dose-response curves of PGF_2α to the right. In digitoninpermeabilized astrocytes, phloretin (100 μ M ) inhibited the stimulation induced by PGF_2α (1 μ M ) plus GTPγS (50 μ M ) without affecting that induced by GTPγS alone. PGF_2α at 1 μ M transiently increased astrocytic intracellular Ca²⁺ concentration in 39% of the cells tested. The response was completely blocked by 100 μ M phloretin and the calcium response recovered again after washing out phloretin. These results suggest that phloretin is an antagonist of PGF_2α receptor linked to phospholipase C in astrocytes.     

Conformational Changes Relevant to Channel Activity and Folding within the first Nucleotide Binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator

Deletion of Phe-508 (F508del) in the first nucleotide binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) leads to defects in folding and channel gating. NMR data on human F508del NBD1 indicate that an H620Q mutant, shown to increase channel open probability, and the dual corrector/potentiator CFFT-001 similarly disrupt interactions between β-strands S3, S9, and S10 and the C-terminal helices H8 and H9, shifting a preexisting conformational equilibrium from helix to coil. CFFT-001 appears to interact with β-strands S3/S9/S10, consistent with docking simulations. Decreases in T(m) from differential scanning calorimetry with H620Q or CFFT-001 suggest direct compound binding to a less thermostable state of NBD1. We hypothesize that, in full-length CFTR, shifting the conformational equilibrium to reduce H8/H9 interactions with the uniquely conserved strands S9/S10 facilitates release of the regulatory region from the NBD dimerization interface to promote dimerization and thereby increase channel open probability. These studies enabled by our NMR assignments for F508del NBD1 provide a window into the conformational fluctuations within CFTR that may regulate function and contribute to folding energetics.     

Characterization of 1-(2-[18F] fluoro-3-pyridyl)-4-(2-isopropyl-1-oxo- isoindoline-5-yl)-5-methyl-1H-1,2,3-triazole, a PET ligand for imaging the metabotropic glutamate receptor type 1 in rat and monkey brains

Neurovascular degeneration contributes to the pathogenesis of Alzheimer's disease (AD). Because erythropoietin (EPO) promotes endothelial regeneration, we investigated the therapeutic effects of EPO in animal models of AD. In aged Tg2576 mice, EPO receptors (EPORs) were expressed in the cortex and hippocampus. Tg2576 mice were treated with daily injection of EPO (5000 IU/kg/day) for 5 days. At 14 days, EPO improved contextual memory as measured by fear-conditioning test. EPO enhanced endothelial proliferation and the level of synaptophysin expression in the brain. EPO also increased capillary density, and decreased the level of the receptor for advanced glycation endproducts (RAGE) in the brain, while decreasing in the amount of amyloid plaque and amyloid-β (Aβ). In cultured human endothelial cells, EPO enhanced angiogenesis and suppressed the expression of the RAGE. These results show that EPO improves memory and ameliorates endothelial degeneration induced by Aβ in AD models. This pre-clinical evidence suggests that EPO may be useful for the treatment of AD.     

猪CAST基因多态性与肌纤维组织学特性及屠宰性状的相关性分析

采用3种限制性核酸内切酶对45头金皮(金华×皮特兰)F₂代猪钙蛋白酶抑制蛋白基因(CAST)的第6外显子和第7外显子之间的片段进行了PCR-RFLP分析, 结果显示在第6内含子内均检测到MspⅠ、HinfⅠ和RsaⅠ酶切多态性。根据酶切结果将CAST基因分为3种基因型(AACCEE、BBDDFF、ABCDEF), 其基因型频率分别为0.1778, 0.2222, 0.6000。对背最长肌做连续性石蜡切片, 分别采用苏木精-伊红和肌球蛋白重链免疫组织化学方法染色并拍照, ImageJ软件统计肌纤维横截面积、密度、直径及MHCⅠ型肌纤维的比例。采用SPSS程序分析了CAST不同基因型对金皮F₂代猪肌纤维组织学特性和屠宰性状的影响。结果表明: BBDDFF基因型个体的肌纤维横截面积和眼肌面积显著地高于ABCDEF基因型个体的肌纤维横截面积和眼肌面积(P < 0.05)。     

病毒侵染对西伯利亚百合DNA甲基化的影响

采用基于AFLP的甲基化敏感扩增多态性(MSAP)技术,用10对引物对侵染百合花叶病毒和丛簇病毒的西伯利亚百合植株和无毒植株进行DNA甲基化水平和模式分析.结果发现,西伯利亚百合无毒植株和病毒侵染植株的平均甲基化水平分别为40.1%和31.5%;平均全甲基化率分别为13.0%和9.7%;半甲基化率分别为27.1%和21.8%.研究表明,百合DNA甲基化多以半甲基化的形式存在;病毒侵染导致百合植株DNA甲基化水平降低,且对整体甲基化水平、全甲基化水平和半甲基化水平均产生了影响;说明病毒侵染百合后植株出现的症状在一定程度上与DNA甲基化存在关联.     

Alginate beads as a storage, delivery and containment system for genetically modified PCB degrader and PCB biosensor derivatives of Pseudomonas fluorescens F113

Aims: Pseudomonas fluorescens F113Rifpcb is a genetically engineered rhizosphere bacterium with the potential to degrade polychlorinated biphenyls (PCBs). F113Rifpcbgfp and F113L::1180gfp are biosensor strains capable of detecting PCB bioavailability and biodegradation. The aim of this paper is to evaluate the use of alginate beads as a storage, delivery and containment system for use of these strains in PCB contaminated soils. Methods and Results: The survival and release of Ps. fluorescens F113Rifpcb from alginate beads were evaluated. Two Ps. fluorescens F113‐based biosensor strains were encapsulated, and their ability to detect 3‐chlorobenzoate (3‐CBA) and 3‐chlorobiphenyl (3‐CBP) degradation in soil was assessed. After 250 days of storage, 100% recovery of viable F113Rifpcb cells was possible. Amendments to the alginate formulation allowed for the timed release of the inoculant. Encapsulation of the F113Rifpcb cells provided a more targeted approach for the inoculation of plants and resulted in lower inoculum populations in the bulk soil, which may reduce the risk of unintentional spread of these genetically modified micro‐organisms in the environment. Encapsulation of the biosensor strains in alginate beads did not interfere with their ability to detect either 3‐CBA or 3‐CBP degradation. In fact, detection of 3‐CBP degradation was enhanced in encapsulated biosensors. Conclusions: Alginate beads are an effective storage and delivery system for PCB degrading inocula and biosensors. Significance and Impact of the Study: Pseudomonas fluorescens F113Rifpcb and the F113 derivative PCB biosensor strains have excellent potential for detecting and bioremediation of PCB contaminated soils. The alginate bead delivery system could facilitate the application of these strains as biosensors.     

新城疫病毒F蛋白在昆虫细胞中的表达及其融细胞作用

用RT-PCR方法扩增出新城疫病毒标准强毒株F48E8的F基因,并将其克隆到pGEM-T载体,命名为pGEM-NDF.鉴定正确后,以BamHI和XbaI双酶切将F基因从pGEM-NDF中释放出来,并插入到pFast Bac I载体中,得到重组转移载体pFast-NDF.然后将该重组质粒转入含有穿梭质粒的感受态DH10Bac中,通过转座作用获得重组穿梭质粒reBacmid-NDF.再用reBacmid-NDF转染Sf9昆虫细胞,获得含有新城疫病毒F48E8株F基因的重组杆状病毒.间接免疫荧光和Western-blot分析结果表明F蛋白在昆虫细胞中获得表达,而且主要表达于细胞膜上,并使感染重组杆状病毒的昆虫细胞在96h发生融合作用.动物试验表明,表达的F蛋白能够产生中和抗体.本文的研究结果为F蛋白的进一步开发奠定了基础.