Oral tolerance to nickel requires CD4+ invariant NKT cells for the infectious spread of tolerance and the induction of specific regulatory T cells

Previously, oral administration of nickel to C57BL/6 wild-type (WT) mice was shown to render both their splenic T cells and APCs (i.e., T cell-depleted spleen cells) capable of transferring nickel tolerance to naive syngeneic recipients. Moreover, sequential adoptive transfer experiments revealed that on transfer of tolerogenic APCs and immunization, the naive T cells of the recipients differentiated into regulatory T (Treg) cells. Here, we demonstrate that after oral nickel treatment Jalpha18(-/-) mice, which lack invariant NKT (iNKT) cells, were not tolerized and failed to generate Treg cells. However, transfer of APCs from those Jalpha18(-/-) mice did tolerize WT recipients. Hence, during oral nickel administration, tolerogenic APCs are generated that require iNKT cell help for the induction of Treg cells. To obtain this help, the tolerogenic APCs must address the iNKT cells in a CD1-restricted manner. When Jalpha18(-/-) mice were used as recipients of cells from orally tolerized WT donors, the WT Treg cells transferred the tolerance, whereas WT APCs failed to do so, although they proved tolerogenic on transfer to WT recipients. However, Jalpha18(-/-) recipients did become susceptible to the tolerogenicity of transferred WT APCs when they were reconstituted with IL-4- and IL-10-producing CD4(+) iNKT cells. We conclude that CD4(+) iNKT cells are required for the induction of oral nickel tolerance and, in particular, for the infectious spread of tolerance from APCs to T cells. Once induced, these Treg cells, however, can act independently of iNKT cells.     

Design and synthesis of novel Gefitinib analogues with improved anti-tumor activity

There is an urgent need to design and develop new and more potent EGFR inhibitors with improved anti-tumor activity. Here we describe the design and synthesis of two series of 4-benzothienyl amino quinazolines as new analogues of the EGFR inhibitor Gefitinib. The anti-tumor activity of these novel Gefitinib analogues in 6 human cancer cell lines was examined. Compared with the parental Gefitinib, most of the new compounds show a markedly increased cytotoxicity to cancer cells. Furthermore, several of the series B compounds that side chains at position 7 contain either a methyl or ethyl group are potent pan-RTK inhibitors. Two representative compounds in this class, 15 and 17, have an enhanced capability to inhibit cancer cell growth and induce apoptosis in vitro and inhibit tumor formation in vivo in human cancer cells with high HER-2, as compared with the parental Gefitinib. Thus they may be promising lead compounds to be developed as an alternative for current Gefitinib therapy or for Gefitinb-resistant patients, potentially via simultaneously blocking multiple RTK signaling pathways.     

Neuropathy target esterase: An essential enzyme for neural development and axonal maintenance

Neuropathy target esterase (NTE) is an endoplasmic reticulum-anchored protein conserved across species. The N-terminal regulatory region of NTE contains three cyclic nucleotide binding domains while the C-terminal catalytic domain has a patatin domain. The NTE gene is expressed in mouse early at embryonic day 7 and its expression is maintained throughout embryonic development. NTE protein is mainly distributed in the nervous system with a pattern that is more restricted to large neurons in older animals. NTE regulates phospholipid metabolism and is known to be a phospholipase B. Knockout of NTE is embryonic lethal in mice, indicating that NTE is essential for embryonic survival. Neuronal specific NTE knockouts survive to adulthood, but show vacuolation and neuronal loss characteristic of neurodegenerative diseases. Recently, mutations in human NTE have been shown to cause a hereditary spastic paraplegia called NTE-related motor neuron disorder, suggesting a critical role for NTE in the nervous system.     

Distinct contributions from the hindbrain and mesenchyme to inner ear morphogenesis

A mature inner ear is a complex structure consisting of vestibular and auditory components. Microsurgical ablations, rotations, and translocations were performed in ovo to identify the tissues that control inner ear morphogenesis. We show that mesenchyme/ectoderm adjacent to the developing ear specifically governs the shape of vestibular components - the semicircular canals and ampullae - by conferring anteroposterior axial information to these structures. In contrast, removal of individual hindbrain rhombomeres adjacent to the developing ear preferentially affects the growth and morphogenesis of the auditory subdivision, the cochlear duct, or basilar papilla. Removal of rhombomere 5 affects cochlear duct growth, while rhombomere 6 removal affects cochlear growth and morphogenesis. Rotating rhombomeres 5 and 6 along the anteroposterior axis also impacts cochlear duct morphogenesis but has little effect on the vestibular components. Our studies indicate that discrete tissues, acting at a distance, control the morphogenesis of distinct elements of the inner ear. These results provide a basis for identifying factors that are essential to vestibular and auditory development in vertebrates.     

白介素-6对NMDA诱导的小脑神经元放电活动的抑制作用及其机制

目的：观察白介素-6（IL-6）对N-甲基-D-天冬氨酸（NMDA）激发的神经元放电活动的影响及其可能的作用机制。方法：用含IL-6、NMDA和JAK抑制剂ACA90的人工脑脊液（ACSF）灌流小脑脑片,利用离体脑片神经元单位放电细胞外记录技术,记录药物对小脑间位核神经元放电的影响。用Western blot法测定间位核神经元NMDA受体亚单位1（NRI）的磷酸化水平。结果：单独用12．5μmol／L和25μmol／LNMDA灌流,神经元放电频率均较基础放电频率增加;用不同浓度IL-6（50,100,200μg／ml）联合NMDA作用后,神经尤的放电频率出现浓度依赖性地降低;AG490可部分阻断IL-6对NMDA兴奋神经元放电的抑制作用。与单独NMDA处理组比较,用IL-6联合NMDA处理神经元后,神经元的NR1磷酸化水平出现浓度依赖性地降低。AG490可阻断IL-6所致的神经元NR1磷酸化水平的降低。结论：IL-6可抑制NMDA激发的小脑间位核神经元的放电兴奋活动;并同时下调神经元的NR1磷酸化水平。     

Snail基因及其蛋白、E-cadherin蛋白在胃癌中的表达及其临床意义

目的观察Snail mRNA及其蛋白、E-cadherin蛋白在胃癌组织中的表达及其与胃癌临床病理特征的关系,并探讨它们在胃癌发生、发展中的作用及其临床应用价值。方法收集96例手术切除胃癌标本,同时取80例癌旁组织作为对照。应用免疫组织化学S-P法检测胃癌组织、癌旁组织中snail蛋白、E-cadherin蛋白的表达;运用原位分子杂交技术检测胃癌组织、癌旁组织中Snail mRNA的表达。结果（1）Snail蛋白在胃癌组织阳性率（83.3%）显著高于癌旁组织（41.25%）（P〈0.05）;高、中分化组Snail蛋白阳性表达率显著低于低分化组（P〈0.05）;Snail蛋白的阳性表达率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;Snail蛋白的表达与胃癌浸润深度、淋巴结转移及远处转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位及临床分期无关（P〉0.05）;（2）胃癌组织中snail mR-NA的阳性率（76%）显著高于癌旁组织（30%）（P〈0.05）;高、中分化组Snail mRNA阳性表达率显著低于低分化组（P〈0.05）;Snail mRNA的阳性表达率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;Snail mRNA的表达与浸润深度及淋巴结转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位、临床分期及远处转移无关（P〉0.05）;（3）E-cadherin蛋白在胃癌组织阳性率（37.5%）显著低于癌旁组织（100%）（P〈0.05）;高、中分化组E-cadherin蛋白阳性率显著高于低分化组（P〈0.05）;E-cadherin蛋白阳性率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;E-cadherin蛋白的表达与胃癌浸润深度、淋巴结转移、临床分期及远处转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位均无关（P〉0.05）;（4）胃癌组织中snail mRNA和snail蛋白的表达呈正相关（r=0.594,P〈0.05）;Snail蛋白和E-cadherin蛋白的表达呈负相关（r=-0.234,P〈0.05）。结论（1）E-cadher-in蛋白低表达与Snail蛋白高表达可能是胃黏膜恶性转变以及胃癌发生浸润转移的重要生物学标志;联合检测E-cadherin蛋白与Snail蛋白对预测胃癌浸润转移有重要意义。（2）Snail蛋白可能在转录水平上调控E-cadherin蛋白的表达。     

Spatial variation of the stable nitrogen isotope ratio of woody plants along a topoedaphic gradient in a subtropical savanna

Variation in the stable N isotope ratio (δ¹⁵N) of plants and soils often reflects the influence of environment on the N cycle. We measured leaf δ¹⁵N and N concentration ([N]) on all individuals of Prosopis glandulosa (deciduous tree legume), Condalia hookeri (evergreen shrub), and Zanthoxylum fagara (evergreen shrub) present within a belt transect 308 m long × 12 m wide in a subtropical savanna ecosystem in southern Texas, USA in April and August 2005. Soil texture, gravimetric water content (GWC), total N and δ¹⁵N were also measured along the transect. At the landscape scale, leaf δ¹⁵N was negatively related to elevation for all the three species along this topoedaphic sequence. Changes in soil δ¹⁵N, total N, and GWC appeared to contribute to this spatial pattern of leaf δ¹⁵N. In lower portions of the landscape, greater soil N availability and GWC are associated with relatively high rates of both N mineralization and nitrification. Both soil δ¹⁵N and leaf [N] were positively correlated with leaf δ¹⁵N of non-N₂ fixing plants. Leaf δ¹⁵N of P. glandulosa, an N₂-fixing legume, did not correlate with leaf [N]; the δ¹⁵N of P. glandulosa’s leaves were closer to atmospheric N₂ and significantly lower than those of C. hookeri and Z. fagara. Additionally, at smaller spatial scales, a proximity index (which reflected the density and distance of surrounding P. glandulosa trees) was negatively correlated with leaf δ¹⁵N of C. hookeri and Z. fagara, indicating the N₂-fixing P. glandulosa may be important to the N nutrition of nearby non-N₂-fixing species. Our results indicate plant ¹⁵N natural abundance can reflect the extent of N retention and help us better understand N dynamics and plant-soil interactions at ecosystem and landscape scales.     

Endogenous hydrogen sulfide reduces airway inflammation and remodeling in a rat model of asthma

Endogenous hydrogen sulfide (H₂S) is hypothesized to have an important role in systemic inflammation. We investigated if endogenous H₂S may be a crucial mediator in airway inflammation and airway remodeling in a rat model of asthma and if endogenous H₂S may exert its anti-inflammatory effect by inhibiting inducible nitric oxide synthase (iNOS)/NO pathway. Cystathionine-γ-lyase (CSE; a H₂S-synthesizing enzyme) was mainly expressed in airway and vascular smooth muscle cells in rat lung tissue. Levels of endogenous H₂S was decreased in pulmonary tissue in ovalbumin (OVA)-treated rats. Exogenous administration of NaHS alleviated airway inflammation and airway remodeling: peak expiratory flow (PEF) increased, goblet cell hyperplasia and collagen deposition score decreased, with decreased total cells recovered from bronchoalveolar fluid (BALF) and influx of eosinophils and neutrophils. The H₂S levels of serum and lung tissue were positively correlated with PEF and negatively correlated with the level of eosinophils and neutrophils in BALF, score of lung pathology. NaHS treatment significantly attenuated pulmonary iNOS activation in OVA-treated rats. These results suggest that the CSE/H₂S pathway plays an anti-inflammatory and anti-remodeling part in asthma pathogenesis and could be a novel target in prevention and treatment of asthma.