FRIL蛋白体外维持脐血造血干/祖细胞的作用及细胞周期调控基因的表达

为探讨新的豆类凝集素(Flt3 receptor-interacting lectin,FRIL)体外维持脐血CD34^ 细胞的作用以及维持过程中细胞周期调控基因HTm4及HTm4S mRNA的表达及意义,我们利用FRIL维持培养脐血CD34^ 细胞,对其增殖曲线、细胞周期及集落形成能力进行常规分析,并用半定量RT—PCR法分别测定FRIL体外维持不同时间后脐血CD34^ 细胞中周期调控基因HTm4及HTm4S mRNA的表达变化。结果显示,FRIL培养的CD34^ 造血干／祖细胞的增殖趋势平缓,整个培养期间细胞增殖倍数不超过起始的3倍：14d之前,FRIL培养细胞的高增殖潜能集落形成细胞(HPP—CFC)形成集落数与FL组无差别,其后则维持高于FL的情况。细胞周期分析则显示,在28d的培养过程内,利用FRIL培养的细胞始终有80％以上维持在G0期;而周期调控基因HTm4及HTm4S在刚分离的脐血CD34^ 细胞中的表达水平较高;但培养1d后,几乎检测不到HTm4基因的表达;培养3～14d,该基因的表达回升并持续维持在高水平。而HTm4S基因的表达在第7d达最高水平,其余时间基本呈稳定表达。转染HTm4和HTm4S,亚细胞定位结果显示HTm4主要定位于核周围,而HTm4S则定位于整个胞浆,由此可能导致它们功能的区别。以上结果提示,长期培养体现出FRIL在维持造血干／祖细胞多能性上的优势;细胞周期调控基因HTm4及其新剪接子参与了FRIL体外长期维持脐血造血干／祖细胞处于静息状态的过程。     

Inhibition of IFN-gamma receptor signaling by hepatitis C virus non-structural protein NS4B]

The function of NS4B is incompletely understood. The aim of the study is to understand the influence of NS4B on anti-viral response. After cell line stably expressing NS4B established, the influence of IFN-alpha of different concentration on VSV was studied using plaque assay; cell expression profiling caused by NS4B was studied using DNA microarray, and the IFNGR1 fluorescence intensity was analyzed. Our data showed that HCV-NS4B could suppress immuno-associated gene expression, in particular, IFN-gamma receptor signal transduction-related genes. Taken together, NS4B could play some roles in HCV resistance to IFN therapy.     

Diallyl trisulfide induces apoptosis and inhibits proliferation of A549 cells in vitro and in vivo

Lung cancer is the leading cause of cancer-related mortality all over the world. In recent years, pulmonary adenocarcinoma has surpassed squamous cell carcinoma in frequency and is the predominant form of lung cancer in many countries. Epidemiological investigations have shown an inverse relationship between garlic (Allium sativum) consumption and death rate from many cancers. Diallyl trisulfide (DATS) is one of the garlic-derived compounds (also known as: organosulfer compounds, OSC). DATS can induce apoptosis and inhibit the growth of many cancer cell lines. Our study demonstrated that the apoptotic incidents induced by DATS were a mitochondria-dependent caspase cascade through a significant decrease of the anti-apoptotic Bcl-2 that resulted in up-regulation of the ratio of Bax/Bcl-2 and the activity of caspase-3, -8, and -9. Eventually, DATS induced the apoptosis and inhibited the proliferation in a concentration- and time-dependent manner. Furthermore, by establishing an animal model of female BALB/c nude mice with A549 xenografts, we found that oral gavage of DATS significantly retarded growth of A549 xenografts in nude mice without causing weight loss or any other side effects compared with the control group. All the evidence both in vitro and in vivo suggested that DATS could be an ideal anti-cancer drug.     

Nicotiana chloroplast genome

Summary Using the existing restriction map and probes from wheat and pea ct-DNA, seven protein genes have been localized in the chloroplast genome of N. tabacum. On the clock-like map, the location of each gene is indicated by its time zone: the 15.2 kD polypeptide of the cytochrome b/f complex at 315, cytochrome f at 430, LS of RuBPCase at 450, both and subunits of ATP synthase at or near 500, proton-translocating subunit of ATP synthase at 820, subunit of ATP synthase at 840 and the 32 kD protein at 930. The genome organization of Nicotiana chloroplast DNA is similar to spinach.     

Morusin induces apoptosis and suppresses NF-kappaB activity in human colorectal cancer HT-29 cells

Morusin is a pure compound isolated from root bark of Morusaustralis (Moraceae). In this study, we demonstrated that morusin significantly inhibited the growth and clonogenicity of human colorectal cancer HT-29 cells. Apoptosis induced by morusin was characterized by accumulation of cells at the sub-G₁ phase, fragmentation of DNA, and condensation of chromatin. Morusin also inhibited the phosphorylation of IKK-α, IKK-β and IκB-α, increased expression of IκB-α, and suppressed nuclear translocation of NF-κB and its DNA binding activity. Dephosphorylation of NF-κB upstream regulators PI3K, Akt and PDK1 was also displayed. In addition, activation of caspase-8, change of mitochondrial membrane potential, release of cytochrome c and Smac/DIABLO, and activation of caspase-9 and -3 were observed at the early time point. Downregulation in the expression of Ku70 and XIAP was exhibited afterward. Caspase-8 or wide-ranging caspase inhibitor suppressed morusin-induced apoptosis. Therefore, the antitumor mechanism of morusin in HT-29 cells may be via activation of caspases and inhibition of NF-κB.     

Myeloid-derived suppressor cells are associated with disease progression and decreased overall survival in advanced-stage melanoma patients

Myeloid-derived suppressor cells are increased in the peripheral blood of advanced-stage cancer patients; however, no studies have shown a correlation of these immunosuppressive cells with clinical outcomes in melanoma patients. We characterized the frequency and suppressive function of multiple subsets of myeloid-derived suppressor cells in the peripheral blood of 34 patients with Stage IV melanoma, 20 patients with Stage I melanoma, and 15 healthy donors. The frequency of CD14⁺ MDSCs (Lin^? CD11b⁺ HLA-DR^? CD14⁺ CD33⁺) and CD14^? MDSCs (Lin^? CD11b⁺ HLA-DR^? CD14^? CD33⁺) was increased in the peripheral blood of Stage IV melanoma patients relative to healthy donors. The frequency of CD14⁺ and CD14^? MDSCs correlated with each other and with the increased frequency of regulatory T cells, but not with classically defined monocytes. CD14^? MDSCs isolated from the peripheral blood of Stage IV melanoma patients suppressed T cell activation more than those isolated from healthy donors, and the frequency of these cells correlated with disease progression and decreased overall survival. Our study provides the first evidence that the frequency of CD14^? MDSCs negatively correlates with clinical outcomes in advanced-stage melanoma patients. These data indicate that suppressive MDSCs should be considered as targets for future immunotherapies.     

Resistin induces monocyte-endothelial cell adhesion by increasing ICAM-1 and VCAM-1 expression in endothelial cells via p38MAPK-dependent pathway

Resistin, firstly reported as an adipocyte-specific hormone, is suggested to be an important link between obesity and diabetes. Recent studies have suggested an association between resistin and atherogenic processes. The adhesion of circulating monocytes to endothelial cells is a critical step in the early stages of atherosclerosis. The purpose of the present study was to investigate the effect of resistin on the adhesion of THP-1 monocytes to human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. Our results showed that resistin caused a significant increase in monocyte adhesion. In exploring the underlying mechanisms of resistin action, we found that resistin-induced monocyte adhesion was blocked by inhibition of p38MAPK activation using SB203580 and SB202190. Furthermore, resistin increased the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by HUVECs and these effects were also p38MAPK-dependent. Resistin-induced monocyte adhesion was also blocked by monoclonal antibodies against ICAM-1 and VCAM-1. Taken together, these results show that resistin increases both the expression of ICAM-1 and VCAM-1 by endothelial cells and monocyte adhesion to HUVECs via p38MAPK-dependent pathways.     

阿片类物质在中枢神经系统的免疫调控作用

内源及外源性阿片具有调节神经元与胶质细胞的功能,这些调节具有保护或损伤脑功能的双重作用。吗啡具有促进受病毒复制及继发感染的作用。另一方面,阿片受体中的ｋａｐｐａ受体可能具有保护神经元的作用。更深层次的研究应是了解阿片通过什么机制作用在胶质细胞和神经元上,藉此以促进研制出具有明显疗效的新药。     

Design and comparison of gene-pyramiding schemes in animals

Marker-assisted gene pyramiding provides a promising way to develop new animal breeds or lines, in which genes responsible for certain favorable characters identified in different breeds or lines are incorporated. In consideration of features of animal populations, we proposed five schemes for pyramiding three genes, denoted Scheme A-E, and five schemes for pyramiding four genes, denoted Scheme F-J. These schemes are representative of the possible alternatives. We also provided an algorithm to compute the population sizes needed in each generation. We compared these schemes with respect to the total population size and the number of generations required under different situations. The results show that there is no scheme that is optimal in all cases. Among the schemes for pyramiding three genes from three lines (L1, L2 and L3), Scheme D (a three-way cross between the three lines are first performed, followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) has a significant advantage over the other schemes when the recombination rate between adjacent genes ranges from 0.1 to 0.4, while Scheme A (a two-way cross between L1 and L2 and a subsequent intercross are performed, followed by a cross with L3 and a subsequent intercross to obtain the desired genotype) is optimal when recombination rate is 0.5. Among schemes for pyramiding four genes from four lines (L1, L2, L3 and L4), Scheme I (seperately, a two-way cross between L1 and L2 (L3 and L4) followed by a backcross to L1 (L3) and a subsequent intercross are performed, then the offspring from the two sides are crossed and followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) is optimal when the recombination rate ranges from 0.1 to 0.4, while Scheme F (cross and subsequent intercross between the four lines are performed successively) is the optimal when the recombination rate is 0.5. We also disscuss how the animals' reproductive capacity, the probabilities of obtaining the desired genotypes and genetic distance between adjacent genes would affect the design of an optimal scheme.