TAT-凋亡素融合蛋白的表达及其抗肿瘤活性

凋亡素(apoptin)由鸡贫血病毒vp3基因编码,能特异地诱导肿瘤细胞凋亡而对正常细胞 没有毒性,为了获得可转导入细胞内部的凋亡素,将人工合成的编码TAT蛋白转导结构域的DNA片段与凋亡素编码基因克隆入质粒pET-28a内,构建出表达融合蛋白TAT-apoptin的原核表达载体pET-28a-TAT-apoptin.在大肠杆菌Rosetta（DE3）中表达融合蛋白,利用IDA -Ni2+ 亲和柱纯化,葡聚糖凝胶G 25除去尿素后得到可溶的变性蛋白.纯化后的TAT apoptin加入体外培养的人脐静脉内皮细胞(HUVECs)和人肺癌Anip973细胞,对照组加入TAT-麦芽糖结合蛋白（TAT-MBP）. 经免疫组化检测,转导1 h后TAT-MBP分布于以上两种细胞的胞浆和胞核,TAT-apoptin则主要分布于2种细胞的胞浆内,转导24 h后TAT-MBP的亚细胞定位没有变化,TAT-apoptin分别定位于HUVECs的胞浆和Anip973的胞核中.脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）显示转导48 h后,TAT-MBP处理过的 HUVECs和Anip973细胞、TAT-apoptin处理过的HUVECs没有明显改变,而TAT-apoptin处理过的Anip973细胞大量凋亡.以上结果表明TAT apoptin融合蛋白在肿瘤治疗上有潜在的应用价值.     

过表达E2F6基因抑制BRD7基因启动子活性

BRD7基因是采用cDNA代表性差异分析法克隆的一个新Bromodomain基因(GenBank 登录号AF152604)。它在鼻咽癌细胞和组织中表达明显下调,过表达BRD7基因可抑制鼻咽癌细胞的生长和细胞周期的进程。前期工作已克隆了BRD7基因启动子区,并将其启动子定位于450bp（-404→+46bp）的区域。为了进一步揭示BRD7基因在鼻咽癌细胞和组织中表达下调的分子机制,生物信息学分析表明BRD7启动子区有E2F6转录因子结合位点,电泳迁移率实验结果表明转录因子E2F6特异性地结合于BRD7启动子区。荧光素酶检测和绿色荧光蛋白表达检测都证实过表达E2F6基因能抑制BRD7基因启动子活性     

The effects of leflunomide on clinical parameters and serum levels of IL-6, IL-10, MMP-1 and MMP-3 in patients with resistant rheumatoid arthritis

OBJECTIVE: The purpose of this open pilot study was to assess possible mechanisms of the effects of leflunomide by studying the influence of the drug on the serum levels of MMP-1, MMP-3, IL-10, IL-6 and their possible correlation with clinical disease parameters. PATIENTS AND METHODS: Thirty patients with long standing active rheumatoid arthritis were enrolled in this study. All patients failed at least 5 DMARDs in the past and were on stable treatment for at least 3 months before starting the protocol. The patients received a loading dose of 100 mg for 3 days followed by 20 mg/day thereafter and followed up monthly for 6 months. Disease activity was assessed at baseline, 2 weeks, and every month of therapy thereafter using the following variables: tender joint count, swollen joint count, morning stiffness duration, pain, tiredness, physician's and patient's global assessment, using VAS, ESR and CRP. Clinical effects of the treatment regimen were calculated using the American College of Rheumatology (ACR) criteria for clinical response. Adverse events were recorded. Serum levels of MMP-1, MMP-3, IL-10 and IL-6 were measured before and 3 months after starting the protocol. RESULTS: Except for tiredness, a statistically significant improvement in all clinical and laboratory parameters of disease activity was reached after 3 months. At this time point the ACR-20 response rate was 46.2%. The levels of MMP-1, MMP-3, IL-6 and IL-10 decreased significantly after 3 months. A statistically significant correlation between serum levels of MMP-1, IL-10 and IL-6 and clinical and laboratory parameters was also shown. After 6 months, 16 out of 30 patients withdrew from the study [adverse events (35.4%), lack of efficacy (9.7%), and low compliance (6.4%)]. CONCLUSIONS: Leflunomide was clinically efficacious in this group of long standing resistant RA in an open study "real life" design. These results comply with those reported in previous clinical trials. Serum MMP-1, MMP-3, IL-10 and IL-6 levels decreased significantly. Despite high withdrawal rate, no serious adverse effects were recorded.     

Glycyrrhizin inhibits neutrophil-associated generation of alternatively activated macrophages

Patients with severe burn injuries are extremely susceptible to infection, and the host's antibacterial responses are frequently suppressed by alternatively activated macrophages (M2Mphi), commonly demonstrated in these patients. An immunosuppressive subset of neutrophils (PMN-II), demonstrated in the peripheral blood of thermally injured patients, has been described as an inducer of M2Mphi. In the present studies, the inhibitory effect of glycyrrhizin (GL) on M2Mphi generation stimulated by PMN-II was examined. M2Mphi were generated from resident Mphi (R-Mphi, lower chamber) after cultivation with PMN-II (upper chamber) in a dual-chamber transwell. However, M2Mphi were not generated from R-Mphi when the same transwell cultures were performed in the presence of GL. M2Mphi were not generated from R-Mphi after cultivation with PMN-II previously treated with GL, while R-Mphi previously treated with GL converted to M2Mphi after they were cultured with PMN-II in transwells. Interleukin-10 and CCL2 released from PMN-II were shown to be effector molecules responsible for the generation of M2Mphi. However, these soluble factors were not produced by PMN-II treated with GL. These results indicate that GL inhibits PMN-II-stimulated M2Mphi generation through the inhibition of CCL2/interleukin-10 production by PMN-II.     

Expression pattern of Filamin-240 in Drosophila blood cells

The expression pattern of Filamin-240 was studied in subsets of Drosophila blood cells by means of immunofluorescent staining and Western blot analysis with use of an antibody specific to a "filamin-folding domain", a consensus motif profile generated from the 20 existing filamin repeats. Expression of Filamin-240 is restricted to lamellocytes - a special blood cell type of the cellular immune response - and is involved in the regulation of lamellocyte development. In the cher1 homozygous larvae, which lack Filamin-240 protein, a vigorous lamellocyte differentiation occurs which is further enhanced upon in vivo immune challenge by a parasitic wasp, Leptopilina boulardi. By introducing a full-length transgene encoding the Drosophila Filamin-240 protein into the cher1 Filamin-deficient homozygous mutant, the mutant blood cell phenotype was rescued. These data demonstrate that the expression of Filamin-240 is strictly lamellocyte specific in Drosophila blood cells and that the protein is a suppressor of lamellocyte development.     

Culture of neural stem cells in calcium alginate beads

Neural stem cells (NSCs) with the capacity of extensive self-renewal and multilineage differentiation have attracted more and more attention in research as NSCs will play an important role in the nerve disease treatment and nerve injury repair. The shortage of NSCs, both their sources and their numbers, however, is the biggest challenge for their clinic application, and hence, in vitro culture and expansion of NSCs is vitally important to realize their potentials. In this work, mouse-derived NSCs were cultured in three-dimensional calcium alginate beads (Ca-Alg-Bs). Gelling conditions, cell density, and cell harvest were determined by the exploration of formation and dissociation parameters for Ca-Alg-Bs. Additionally, the recovered and the subsequent induced cells were identified by immunofluorescence staining of Nestin, beta-tubulin, and GFAP. The results show that the 2-mm diameter Ca-Alg-Bs, prepared with 1.5% sodium alginate solution and 3.5% CaCl2 solution and with gelling for 10 min, is suitable for the NSCs culture. The seeding density of 0.8 x 10(5) cells x mL-1 for the encapsulation of NSCs resulted in the most expansion, and the NSCs almost doubled during the experiment. The average cell recovery rate is over 88.5%, with the Ca-Alg-Bs dissolving in 55 mM sodium citrate solution for 10 min. The recovered cells cultured in the Ca-Alg-Bs still expressed Nestin and had the capacity of multilineage differentiation into neurons and glial cells and, thus, remained to be NSCs. These results demonstrate that NSC expansion within Ca-Alg-Bs is feasible and provides further possibilities for NSC expansion in bioreactors of the scale of clinical relevance.     

Three mammalian cytochromes b561 are ascorbate-dependent ferrireductases

Cytochromes b(561) are a family of transmembrane proteins found in most eukaryotic cells. Three evolutionarily closely related mammalian cytochromes b(561) (chromaffin granule cytochrome b, duodenal cytochrome b, and lysosomal cytochrome b) were expressed in a Saccharomyces cerevisiaeDeltafre1Deltafre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity, to study their ability to reduce ferric iron (Fe(3+)). The expression of each of these cytochromes b(561) was able to rescue the growth defect of the Deltafre1Deltafre2 mutant cells in iron-deficient conditions, suggesting their involvement in iron metabolism. Plasma membrane ferrireductase activities were measured using intact yeast cells. Each cytochrome b(561) showed significant FeCN and Fe(3+)-EDTA reductase activities that were dependent on the presence of intracellular ascorbate. Site-directed mutagenesis of lysosomal cytochrome b was conducted to identify amino acids that are indispensable for its activity. Among more than 20 conserved or partially conserved amino acids that were investigated, mutations of four His residues (H47, H83, H117 and H156), one Tyr (Y66) and one Arg (R67) completely abrogated the FeCN reductase activity, whereas mutations of Arg (R149), Phe (F44), Ser (S115), Trp (W119), Glu (E196), and Gln (Q131) affected the ferrireductase activity to some degree. These mutations may affect the heme coordination, ascorbate binding, and/or ferric substrate binding. Possible roles of these residues in lysosomal cytochrome b are discussed. This study demonstrates the ascorbate-dependent transmembrane ferrireductase activities of members of the mammalian cytochrome b(561) family of proteins.     

Flow-cytometric assessment of cellular poly(ADP-ribosyl)ation capacity in peripheral blood lymphocytes

Background  

Poly(ADP-ribosyl)ation is a posttranslational modification of nuclear proteins catalysed by poly(ADP-ribose) polymerases (PARPs), using NAD⁺ as a substrate. Activation of PARP-1 is in immediate response to DNA damage generated by endogenous and exogenous damaging agents. It has been implicated in several crucial cellular processes including DNA repair and maintenance of genomic stability, which are both intimately linked with the ageing process. The measurement of cellular poly(ADP-ribosyl)ation capacity, defined as the amount of poly(ADP-ribose) produced under maximal stimulation, is therefore relevant for research on ageing, as well as for a variety of other scientific questions.     

Effects of high-relief structures on cold temperate fish assemblages: A field experiment

High-relief structures may influence the abundance and diversity of reef-associated fish. We conducted a field experiment to investigate whether the presence of vertical structures (PVC pipes) affects fish communities on artificial reefs. The effect of the height of the structures (1 and 3 m) was also tested. Furthermore, the effects on fish of placing artificial reefs on otherwise featureless bottoms were quantified. Algal and macro-invertebrate colonization of the reefs was also recorded. The experiment was carried out on the west coast of Sweden over a period of 1 year. The vertical structures had a positive effect on fish abundance but not on diversity. The height of the structures did not, however, influence the fish communities. Natural as well as urban vertical structures on the seafloor could have a positive effect on local fish abundance. The positive effects of artificial reefs on total fish abundance and diversity were immediate. Of the 10 species recorded, two, the black goby Gobius niger and the goldsinny wrasse Ctenolabrus rupestris, dominated over the whole survey period. There were significant temporal differences in fish abundance, and diversity increased with time.