Porphyromonas gingivalis fimbriae induce unique dendritic cell subsets via Toll-like receptor 2

Backgound and Objective:  Dendritic cells (DCs) play a critical role in the activation of T cells as well as in shaping immune responses. We have reported previously that Porphyromonas gingivalis lipopolysaccharides ( Pg LPS) induced a CD14⁺CD16⁺ DC subset with a weak immuno-stimulatory activity. In contrast, Escherichia coli LPS ( Ec LPS) induced fully matured DCs with strong immunostimulatory activities. Since Pg LPS as well as Pg fimbriae have been indicated to work as Toll-like receptor (TLR) 2 ligands, we speculate that the TLR usage of bacterial antigens may be critical for DC maturation.
Material and Methods:  We investigated the effect of Pg fimbriae on the phenotype and function of human peripheral blood DCs in comparison with a TLR2 ligand, peptidoglycan, and a TLR4 ligand, Ec LPS.
Results:  Flow cytometry revealed that Pg fimbriae and peptidoglycan but not Ec LPS induced CD14 and CD16 expression on peripheral blood DCs (CD14⁻CD16⁻). A monoclonal antibody against TLR2 abrogated this induction, but an antibody against TLR4 had no effect. Dendritic cells stimulated with Pg fimbriae had a weaker capability to induce allogenic T cell proliferation and exhibited a weaker production of interleukin-8 and regulated upon activation, normal T cell expressed and secreted (RANTES) than DCs stimulated with Ec LPS.
Conclusion:  These results indicate that different TLR usage affects mature DC phenotype and function and is thus crucial to the regulation of immunity to the pathogen.     

Distinct patterns of neuronal inputs and outputs of the juxtaparaventricular and suprafornical regions of the lateral hypothalamic area in the male rat

We have analyzed at high resolution the neuroanatomical connections of the juxtaparaventricular region of the lateral hypothalamic area (LHAjp); as a control and in comparison to this, we also performed a preliminary analysis of a nearby LHA region that is dorsal to the fornix, namely the LHA suprafornical region (LHAs). The connections of these LHA regions were revealed with a coinjection tract-tracing technique involving a retrograde (cholera toxin B subunit) and anterograde (Phaseolus vulgaris leucoagglutinin) tracer. The LHAjp and LHAs together connect with almost every major division of the cerebrum and cerebrospinal trunk, but their connection profiles are markedly different and distinct. In simple terms, the connections of the LHAjp indicate a possible primary role in the modulation of defensive behavior; for the LHAs, a role in the modulation of ingestive behavior is suggested. However, the relation of the LHAjp and LHAs to potential modulation of these behaviors, as indicated by their neuroanatomical connections, appears to be highly integrative as it includes each of the major functional divisions of the nervous system that together determine behavior, i.e., cognitive, state, sensory, and motor. Furthermore, although a primary role is indicated for each region with respect to a particular mode of behavior, intermode modulation of behavior is also indicated. In summary, the extrinsic connections of the LHAjp and LHAs (so far as we have described them) suggest that these regions have a profoundly integrative role in which they may participate in the orchestrated modulation of elaborate behavioral repertoires.     

Myelination in the human hippocampal formation from midgestation to adulthood

Myelination, one of the last steps of neuronal development, was examined in the human fetal and postnatal hippocampal formation using immunohistochemistry to detect a protein component of the myelin sheath, the myelin basic protein synthesized by oligodendroglial cells. Myelin basic protein-immunoreactive oligodendroglial cells were first seen at the 20th gestational week in the fimbria fornicis and in the alveus. Between the 21st and 35th weeks, myelinated axons also appeared in the fimbria fornicis. At the age of 39 gestational weeks, short and thin myelinated fibers were present in the fimbria, in the alveus, and less so in the stratum oriens of the hippocampus, while the first oligodendroglial cells appeared in the stratum lacunosum-moleculare and in the hilus. By the 2nd postnatal week myelinated fibers appeared in the stratum lacunosum-moleculare of Ammon's horn. At the 3rd month, myelination was strong in the alveus, moderate in the strata oriens, lacunosum-moleculare and radiatum of Ammon's horn, while only a small number of myelinated fibers were detected in the hilus. By the 5th month, the first oligodendroglial cells were detected in the molecular layer of the dentate gyrus. Myelination continued in the following years, particularly in the dentate gyrus, where even at the age of 11 years the density of myelinated fibers did not reach the adult level. It appears that the first myelinated axons belong to the long-projecting large hippocampal pyramidal cells and/or to their subcortical and cortical afferents. The sequence of myelination follows the known developmental pattern of hippocampal afferent and efferent pathways, and the prolonged myelination might be a factor in the prolonged functional maturation of hippocampal circuitry.     

米氮平对抑郁症大鼠海马凋亡相关蛋白表达的调节作用

 目的 研究米氮平对抑郁症大鼠模型学习记忆、海马凋亡蛋白Caspase-3和凋亡抑制蛋白Bcl-2异常表达的调节作用。方法 将20只大鼠随机分为对照组、抑郁组和治疗组,制备抑郁症模型及米氮平治疗模型,采用Morris水迷宫实验方法评价学习记忆,应用蛋白免疫印迹杂交方法分析海马Caspase-3蛋白和Bcl-2蛋白表达变化。结果 与对照组比较,抑郁组大鼠在水迷宫实验目标象限内游动时间显著减少（P＜0.01）,海马Caspase-3蛋白表达水平显著增高（P＜0.05）,Bcl-2蛋白表达水平显著降低（P＜0.05）。治疗组大鼠在水迷宫实验目标象限内游动时间较抑郁组增加,海马Caspase-3蛋白表达水平较抑郁组降低,Bcl-2蛋白表达水平较抑郁组升高（P均<0.05）。结论 抑郁症大鼠学习记忆力下降、海马Caspase-3蛋白异常高表达、海马Bcl-2蛋白异常低表达,米氮平使抑郁症大鼠学习记忆力、海马Caspase-3蛋白表达、海马Bcl-2蛋白表达逆转。     

Neurodevelopmental expression and localization of the cellular prion protein in the central nervous system of the mouse

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders caused by PrP^Sc, or prion, an abnormally folded form of the cellular prion protein (PrP^C). The abundant expression of PrP^C in the central nervous system (CNS) is a requirement for prion replication, yet despite years of intensive research the physiological function of PrP^C still remains unclear. Several routes of investigation point out a potential role for PrP^C in axon growth and neuronal development. Thus, we undertook a detailed analysis of the spatial and temporal expression of PrP^C during mouse CNS development. Our findings show regional differences of the expression of PrP, with some specific white matter structures showing the earliest and highest expression of PrP^C. Indeed, all these regions are part of the thalamolimbic neurocircuitry, suggesting a potential role of PrP^C in the development and functioning of this specific brain system. J. Comp. Neurol. 518:1879–1891, 2010. © 2010 Wiley‐Liss, Inc.     

异丙酚对大鼠缺血再灌注海马区Bax和Bcl-2表达的影响

目的 研究异丙酚对缺血再灌注脑损伤大鼠海马区凋亡因子Bax、Bcl-2及大脑梗死体积的影响,探讨异丙酚对脑缺血再灌注损伤的保护作用.方法 Wistar大鼠共40只,随机分为4组,每组10只,S组为假手术组,C组为缺血再灌注损伤对照组,I组为线栓梗塞缺血后异丙酚治疗组,R组为线栓梗塞缺血再灌注后异丙酚治疗组.结果 C组、I组、R组的神经功能缺失体征评分无明显差异(P＞0.05).I组和R组的梗死体积比C组明显减小,差异有统计学意义(均P＜0.01).C组海马区单位面积内细胞核Bax阳性表达的细胞数目较S组、I组、R组升高(均P＜0.05),S组、I组、R组3组之间比较差异无统计学意义(P＞0.05).I组、R组海马区Bcl-2吸光度测定值分别高于C组和S组(均P＜0.05).但C组与S组之间、I组与R组之间比较差异无统计学意义(均P＞0.05).结论 异丙酚可降低缺血再灌注脑损伤大鼠海马区凋亡因子Bax的表达和大脑梗死体积,提高抑制凋亡因子Bcl-2的表达,对缺血再灌注脑损伤有一定保护作用.     

实时聚合酶链反应检测切割穹窿海马伞大鼠海马内磷脂酰乙醇胺结合蛋白mRNA的表达变化

目的探讨切割穹窿海马伞大鼠海马与正常海马内磷脂酰乙醇胺结合蛋白（PEBP）mRNA的表达差异。方法42只SD大鼠随机分成正常对照组和切割穹隆海马伞后1、3、7、14、21及28d组,每组6只。提取各组大鼠的海马组织总RNA,应用实时PCR技术观察切割穹窿海马伞后海马中PEBPmRNA的表达变化。结果PEBPmRNA在切割后3d表达开始上升,7d达最高水平,随后缓慢下降,21d时降至正常。结论切割穹窿海马伞后海马中PEBP的高表达可能与诱导神经干细胞向胆碱能神经元分化的海马神经再生有关。     

Increased number of neural progenitors in human temporal lobe epilepsy

An increased neurogenesis is reported in animal models of mesial temporal lobe epilepsy (MTLE) but the fate of newborn cells is unknown. Here, we attempted to demonstrate neurogenesis in adult epileptic tissue obtained after hippocampectomy. MTLE hippocampi showed increased expression of division markers and of Musashi-1, a marker of neural progenitors, compared to control hippocampi. Large quantities of Musashi-1+ cells were obvious in the subgranular layer and the subventricular zone, both known neurogenic areas, and in the fissura hippocampi. Musashi-1 was expressed by small cells that were mainly vimentin+ or nestin+, rarely Dcx+ or PSA-NCAM+ and negative for markers of mature neurons or astrocytes. Some of them are present in the granular layer, the hilus, and CA1 area resembling the ectopic positions described in rodents. These findings demonstrate that neural progenitors proliferate in chronic epilepsy and suggest that the fissura hippocampi behaves like another neurogenic area.     

切割穹窿海马伞大鼠海马内BLBP的表达变化

为了观察切割大鼠右侧穹窿海马伞后,切割侧与正常侧海马齿状回内脑脂结合蛋白(BLBP)的表达变化,本研究应用Western blot和免疫组织化学方法检测双侧海马内BLBP蛋白表达水平的变化,以及海马齿状回门区和颗粒下层中BLBP免疫阳性细胞数和灰度值。结果显示:正常大鼠双侧海马各区和颗粒下层细胞BLBP仅有微量表达,切割穹窿海马伞后第1 d双侧差异不明显;3 d时切割侧颗粒下层阳性细胞及染色深度较正常侧加深;5 d时切割侧颗粒下层阳性细胞数量明显增多,染色较深,并达到最高水平;7 d后BLBP免疫阳性细胞的数量和染色深度开始降低,14 d时接近正常侧水平。而切割后3、5 d时双侧门区BLBP免疫阳性细胞的数量差异不大,但切割侧染色较深,7 d后也逐渐降低,14 d时降至正常侧水平。上述结果提示,切割穹窿海马伞阻断了隔区与海马齿状回的纤维联系后,可引起海马齿状回门区和颗粒下层BLBP表达增强,可能引发了放射状胶质细胞的增殖和激活,构成的支架有助于神经干细胞的迁移和向神经元的分化。