Neuropsin--a possible modulator of synaptic plasticity

Accumulating evidence has suggested pivotal roles for neural proteases in development, maturation, aging, and cognitive functions. Among such proteases, neuropsin, a kallikrein gene-related (KLK) endoprotease, appears to have a significant plasticity function that has been analyzed primarily in the hippocampal Schaffer-collateral pathway. In this article, after reviewing the general features of neuropsin, its role in Schaffer-collateral synaptic plasticity is discussed in some detail. Enzymatically active neuropsin is necessary to establish the early phase of long-term potentiation (LTP). This type of LTP, which can be elicited by rather weak tetanic stimulation, is significant in synaptic late association between two independent hippocampal synapses. Neuropsin deficiency completely impaired the early phase of LTP, leading to the absence of late associativity. Associations between early and persistent-LTP synapses may be related to mammalian working memory and consequently integration in learning and memory.     

Regulation of T-cell survival and mitochondrial homeostasis by TSC1

The mammalian target of rapamycin (mTOR) is a key regulator of cell growth and metabolism. It associates with multiple proteins and forms two distinct signaling complexes, mTORC1 and mTORC2. Accumulating evidence has revealed critical roles for intact mTOR signaling during T-cell activation and responses to microbial infection. However, the importance of mTOR regulation in T cells has yet to be explored. The TSC1/TSC2 complex has been shown to inhibit mTORC1 signaling in cell line models. We show here that deletion of TSC1 in the murine T-cell lineage results in a dramatic reduction of the peripheral T-cell pool, correlating with increased cell death. While mTORC1 is constitutively activated, mTORC2 signaling, reflected by Akt phosphorylation and activity, is decreased in TSC1-deficient T cells. Furthermore, TSC1-deficient T cells contain elevated reactive oxygen species (ROS) and exhibit decreased mitochondrial content and membrane potential, which is correlated with the activation of the intrinsic death pathway. Overall, our results demonstrate that TSC1 differentially regulates mTORC1 and mTORC2 activity, promotes T-cell survival, and is critical for normal mitochondrial homeostasis in T cells.     

Expression of Pirh2, a p27(Kip1) ubiquitin ligase, in hepatocellular carcinoma: correlation with p27(Kip1) and cell proliferation

p53-Induced ring-H2 protein (Pirh2), a recently identified ubiquitin-protein ligase, interacts with p27(Kip1) to promote ubiquitination of p27(Kip1) independently of p53. High Pirh2 and low p27(Kip1) immunoreactivity are associated with a poor prognosis in several cancers, including resistant phenotypes. In the present study, we investigated the role of Pirh2 and p27(Kip1) in human hepatocellular carcinoma (HCC) progression. Immunohistochemical analysis was performed on formalin-fixed paraffin sections of 87 specimens. Statistical analysis showed that expression of Pirh2 was negatively related to p27(Kip1) expression (r = 0.787; P < .05), and Pirh2 expression correlated significantly with histologic grade (P < .001), venous invasion (P = .004), tumor size (P = .024), and the presence of multiple tumor-bearing lymph nodes (P = .017), whereas p27(Kip1) expression correlated significantly with histologic grade (P < .001), venous invasion (P = .048), and cirrhosis (P = .028). By Kaplan-Meier analysis, the survival curves of low versus high expressers of Pirh2 and p27(Kip1) showed significant separation (P < .01). Molecular interaction could be demonstrated between Pirh2 and p27(Kip1) in three HCC cell lines. In vitro, following release of two HCC cell lines from serum starvation, the expression of Pirh2 was upregulated, whereas p27(Kip1) was downregulated. Our results suggest that Pirh2 mediates the degradation of p27(Kip1) and participates in cell proliferation in human HCC. These findings provide a rational framework for further development of Pirh2 inhibitors as a novel class of anti-tumor agents.     

大鼠肝再生中环状RNA的表达变化及其对细胞增殖的调节作用

目的 探讨环状RNA(circRNA)在大鼠肝再生中的表达变化及其对细胞增殖的调节作用.方法 用生物高通量检测方法分析114只2/3肝切除大鼠诱导的大鼠肝再生中circRNA的表达变化,用miRanda和TargetScan网站分析大鼠肝再生的靶微小RNA(miRNA)及其mRNA,用基因本体论(GO)和IPA软件分析...     

宝乐果提取物8,9-糖基化环烯醚萜苷促进人软骨细胞增殖和抑制凋亡的作用

目的观察宝乐果(Borojo)提取物8,9-糖基化环烯醚萜苷(GIG)对体外培养的人骨关节炎软骨细胞促进增殖和抑制细胞凋亡的作用。方法体外培养人骨关节炎软骨细胞,进行软骨细胞鉴定。用不同浓度(25、50、100、200、400μg/ml)的8,9-糖基化环烯醚萜苷培养人骨关节炎软骨细胞,用硫酸酚嗪甲酯(MTS)法、5-乙炔基-2脱氧尿嘧啶核苷(EdU)法、平板克隆形成实验检测细胞的增殖、流式细胞术观察软骨细胞凋亡,用丙二醛(MDA)法、超氧化物歧化酶(SOD)检测、谷胱甘肽过氧化物酶(GSH-Px)检测观察软骨细胞氧化酶的活性,用Western bolt法检测凋亡相关蛋白表达。结果与对照组相比,随GIG浓度增加,细胞活力升高,差异有统计学意义(P<0.01);细胞核分裂增加,差异有统计学意义(P<0.05);细胞克隆数量增多,差异有统计学意义(P<0.05);细胞周期的S期延长,细胞增殖活跃细胞凋亡率减少;MDA含量下降,差异有统计学意义(P<0.05)。SOD含量升高,差异有统计学意义(P<0.05);GSH-Px含量升高,差异有统计学意义(P<0.05)。结论 GIG可能对软骨细胞具有增殖的作用,而且在观察浓度内,细胞毒性小,并可抑制细胞凋亡,提示其有潜在能力可能成为治疗骨关节炎的一种策略。     

CRIP1a switches cannabinoid receptor agonist/antagonist-mediated protection from glutamate excitotoxicity

A shared pathology among many neurological and neurodegenerative disorders is neuronal loss. Cannabinoids have been shown to be neuroprotective in multiple systems. However, both agonists and antagonists of the CB₁ cannabinoid receptor are neuroprotective, but the mechanisms responsible for these actions remain unclear. Recently a CB₁ receptor interacting protein, CRIP1a, was identified and found to alter CB₁ activity. Here we show that in an assay of glutamate neurotoxicity in primary neuronal cortical cultures CRIP1a disrupts agonist-induced neuroprotection and confers antagonist-induced neuroprotection.     

FVB小鼠骨髓源树突状细胞的培养

目的 建立FVB小鼠骨髓源树突状细胞体外培养和扩增方法,观察其形态和特征.方法 在无菌条件下提取FVB鼠骨髓细胞,分离单个核细胞,用IL-4和GM-CSF联合协同诱导下培养,加用磷酸脂多糖刺激.应用光镜下观察树突状细胞的形态,流色细胞仪检测鉴定其生物学特征.结果 联合培养小鼠骨髓细胞3d后,可见细胞形态发生改变,细胞形...     

Spinal cord histopathology of MOG peptide 35-55-induced experimental autoimmune encephalomyelitis is time- and score-dependent

The neuroprotective effects of Jatrorrhizine from Coptidis Rhizoma against hydrogen peroxide (H(2)O(2))-induced rat pheochromocytoma line PC12 injury and its potential mechanisms were evaluated in the present study. When cells were exposed to H(2)O(2) (200 μM) for 12h, there was a significant reduction in cell survival and activity of antioxidant enzyme (SOD and HO-1) and LDH release. In addition, increased ROS production, declined MMP and increased production of malondialdehyde (MDA) were observed. Preincubation of cells with Jatrorrhizine (0.01-10.0 μM) 24h prior to H(2)O(2) exposure markedly elevated cell viability and activities of antioxidant enzyme (SOD and HO-1), prevented LDH release and lipid peroxidation (MDA) production, attenuated the decrease of MMP and scavenged ROS formation. Jatrorrhizine also attenuated caspase-3 activation of the downstream cascade following ROS. Our results suggest that Jatrorrhizine holds potential for neuroprotective effects against H(2)O(2)-induced injury.     

Nucleosome-induced neutrophil activation occurs independently of TLR9 and endosomal acidification: implications for systemic lupus erythematosus

The nucleosome is a major autoantigen known to activate PMN in systemic lupus erythematosus (SLE). TLR9 recognizes bacterial and even mammalian DNA under certain circumstances. Nevertheless, the role of TLR9 in SLE development is still unclear. Since nucleosomes are composed of DNA, we investigated whether TLR9 is required for nucleosome-induced PMN activation. Isolated neutrophils were cultured with nucleosomes, plasma from lupus patients and other stimuli in the presence/absence of various inhibitors. Cells were analyzed by flow cytometry, ELISA and confocal microscopy. We found that nucleosomes circulating in lupus plasma induce the secretion of pro-inflammatory cytokines by PMN. Nucleosomes activate human PMN independently of unmethylated CpG sequences in nucleosomal DNA, leading to IL-8/IL-6/TNF secretion and CD11b up-regulation. Nucleosomes accumulate in the cytoplasm of PMN upon endocytosis, induce TLR9 up-regulation and act synergistically with TLR9 ligands. Nucleosome-induced activation was not inhibited by polymyxin B (PB), chloroquine (CQ), ammonium chloride (AC) or a TLR9 antagonist. Moreover, both PMN isolated from WT and TLR9-KO mice were activated by nucleosomes, as detected by MIP-2 secretion and CD11b up-regulation. Activation occurred therefore independently of endotoxins, endosomal acidification, TLR9 and CpG motifs. TLR9 may thus be differently required in the triggering of nucleosome-induced innate immunity and anti-nucleosome B-cell autoimmunity.     

Acinetobacter baumannii-induced lung cell death: role of inflammation, oxidative stress and cytosolic calcium

A growing body of evidence supports the notion that susceptible Acinetobacter baumannii strain ATCC 19606 induces human epithelial cells death. However, most of the cellular and molecular mechanisms associated with this cell death remain unknown, and also the degree of the cytotoxic effects of a clinical panresistant strain compared with a susceptible strain has never been studied. Due to the role of proinflammatory cytokine release, oxidative stress and cytosolic calcium increase in the cell death-induced by other Gram-negative bacteria, we investigated whether these intracellular targets were involved in the cell death induced by clinical panresistant 113-16 and susceptible ATCC 19606 strains.