BET抑制剂对弥漫性大B细胞淋巴瘤细胞生长及外周血Th17细胞数量和相关细胞因子表达的影响

目的:探讨溴结构域和超末端结构域（bromodomain and extra terminal domain,BET）抑制剂对弥漫性大B细胞淋巴瘤CRL-2630细胞生长的影响,以及对弥漫性大B细胞淋巴瘤BALB/c-nu裸鼠外周血中辅助性T细胞17（helper T cells,Th17）数量和相关细胞因子表达的影响。方法:培养弥漫性大B细胞淋巴瘤株CRL-2630,使用不同浓度BET抑制剂（2、4、8、16、32 nmol/L）处理48 h,32 nmol/L BET抑制剂处理不同时间（12、24、36、48 h）,CCK-8法检测各处理细胞活性;集落形成实验检测不同BET抑制剂浓度处理后细胞集落形成能力;Annexin V-FITC/PI双染法检测不同BET抑制剂浓度处理后细胞凋亡情况;实时荧光定量PCR与Western blot检测32 nmol/L BET抑制剂处理CRL-2630细胞48 h后HMGA1 mRNA与蛋白的表达水平;构建HMGA1过表达载体并通过脂质体介导法转染CRL-2630细胞,并用32 nmol/L BET抑制剂处理48 h,检测细胞活性与凋亡情况;构建裸鼠弥漫性大B细胞淋巴瘤模型并采集外周血,流式细胞术检测Th17细胞比例,ELISA法检测相关细胞因子的含量。结果:在一定范围内,BET抑制剂呈剂量依赖性地抑制CRL-2630细胞的活性,32 nmol/L BET抑制剂以时间依赖性地抑制CRL-2630细胞的活性。随着BET抑制剂处理浓度的增高,CRL-2630细胞集落形成能力逐渐下降,凋亡率逐渐升高。32 nmol/L BET抑制剂处理CRL-2630细胞48 h后,细胞中HMGA1的mRNA和蛋白水平均明显下降。pcDNA3.4-HMGA1转染CRL-2630细胞再使用BET抑制剂处理后,细胞的活性升高而凋亡率明显下降。弥漫性大B细胞淋巴瘤裸鼠经BET抑制剂作用后,外周血Th17细胞比例和IL-6、IL-17、IL-23含量较生理盐水组明显下降。结论:BET抑制剂能有效抑制 CRL-2630细胞活性,并诱导其凋亡,在一定范围内呈时效和量效关系。BET抑制剂还可以抑制弥漫性大B细胞淋巴瘤裸鼠外周血Th17细胞数量和相关细胞炎性因子的分泌,其作用机制可能与HMGA1的表达下调有关。     

多发性内分泌腺瘤病2A型家系临床特点分析及RET基因突变研究

目的检测互不相关的3个多发性内分泌腺瘤病2A型（MEN2A）家系中RET原癌基因突变情况，以探寻其发病的分子机制，同时总结其临床特点。方法收集3个MEN2A家系，共有8例MEN2A患者，3个家系有28位同意进行基因检测，提取28位外周血基因组DNA，对RET原癌基因21个外显子进行聚合酶链反应（PCR），PCR产物进行直接测序，对发现新的突变点进一步进行克隆测序。结果家系1RET原癌基因存在外显子11的C634R突变，家系2为C634Y突变，家系3的4例MEN2A患者均存在D631密码子（GAC）的杂合缺失，碱基序列由TGC∧GACGAGCTG变为TGCGAGCTG，导致代表天冬氨酸的D631的缺失，即del D631。8例MEN2A患者中7例有MTC（87．5％），8例有PCC（100％），未发现有HPT的发生，其中6例（75％）患者是以PCC起病，而且PCC中7例（87．5％）为双侧。结论本研究结果提示中国大陆MEN2A家系存在C634Y突变，也有exon11的D631杂合缺失突变，其中RET基因第11号外显子的D631缺失突变（delD631）是首例报道。D631 del临床特点为发病年龄较迟，肾上腺嗜铬细胞瘤可先于甲状腺髓样癌的发生。     

溴化结构域蛋白抑制剂JQ1对人乳腺癌细胞的作用

目的:研究BET家族小分子抑制剂JQ1对乳腺癌细胞增殖、周期及凋亡的影响及其作用机制。方法:JQ1作用于人乳腺癌细胞MDA-MB-231、MCF-7,采用流式细胞术检测细胞凋亡率及细胞周期的变化,MTT法测定细胞存活曲线,克隆形成法测定细胞抑制率,real-time PCR检测c-MYC的基因表达水平变化。Western blotting方法检测c-MYC及BRD4蛋白表达水平的变化。结果:乳腺癌细胞MDA-MB-231对BRD4抑制剂JQ1敏感,而MCF-7则对JQ1耐受。JQ1可以诱导MDA-MB-231细胞G1期阻滞和凋亡,相同的处理因素作用于MCF-7后,则无明显的细胞周期及凋亡水平的改变。JQ1作用于MDA-MB-231细胞后可以显著下调c-MYC基因及蛋白表达水平,而JQ1作用于耐药的MCF-7后,c-MYC的基因的表达水平升高,而蛋白表达水平无明显改变。结论:BET抑制剂提供了一个潜在的治疗乳腺癌的靶点。     

Direct visualization of membrane clustering and endocytosis of thyrotropin into cultured thyroid cells

We prepared a highly fluorescent conjugate of thyrotropin (TSH) which retains approximately 25% of the binding affinity of native TSH towards TSH receptor and approximately 25% of the potency of the native hormone in stimulating the accumulation of cAMP in thyroid cells. Using an image-intensified microscopy system, we observed that our fluorescent TSH bound specifically to diffusely distributed membrane receptors on live rat or bovine embryo thyroid cells grown in culture. At 37 degrees C the fluorescent hormone formed visible patches which were internalized and subsequently degraded. Hence, TSH, like other polypeptide hormones, is internalized by a process of receptor-mediated endocytosis. The addition of bivalent antibodies against the fluorophore rhodamine, to thyroid cells that were previously exposed to sub-optimal concentrations of rhodamine TSH, elicited maximal stimulation of the thyroid adenyl cyclase. Monovalent Fab' fragments did not enhance the response of rhodamine TSH. Therefore we conclude that enhanced surface clustering of TSH molecules increases their capacity to stimulate the adenyl cyclase of thyroid cells.     

BET蛋白与脑认知功能关系的研究进展

溴结构域和超末端结构域(BET)蛋白能识别乙酰化组蛋白并与之结合,同时与染色质调节因子相互作用或招募转录起始复合物,从而启动基因转录。近几年,BET蛋白抑制剂的合成推进了BET蛋白相关表观遗传学研究。本文综述BET蛋白的结构和功能、BET蛋白抑制剂、BET蛋白在学习和记忆中的作用、BET蛋白在老年痴呆症中的作用以及BET蛋白在药物成瘾中的作用。     

Cerium oxide nanoparticle uptake kinetics from the gas-phase into lung cells in vitro is transport limited

Nowadays, aerosol processes are widely used for the manufacture of nanoparticles (NPs), creating an increased occupational exposure risk of workers, laboratory personnel and scientists to airborne particles. There is evidence that possible adverse effects are linked with the accumulation of NPs in target cells, pointing out the importance of understanding the kinetics of particle internalization.In this context, the uptake kinetics of representative airborne NPs over 30 min and their internalization after 24 h post-exposure were investigated by the use of a recently established exposure system. This system combines the production of aerosolized cerium oxide (CeO₂) NPs by flame spray synthesis with its simultaneous particle deposition from the gas-phase onto A549 lung cells, cultivated at the air-liquid interface.Particle uptake was quantified by mass spectrometry after several exposure times (0, 5, 10, 20 and 30 min). Over 35% of the deposited mass was found internalized after 10 min exposure, a value that increased to 60% after 30 min exposure. Following an additional 24 h post-incubation, a time span, after which adverse biological effects were observed in previous experiments, over 80% of total CeO₂ could be detected intracellularly.On the ultrastructural level, focal cerium aggregates were present on the apical surface of A549 cells and could also be localized intracellularly in vesicular structures. The uptake behaviour of aerosolized CeO₂ is in line with observations on cerium suspensions, where particle mass transport was identified as the rate-limiting factor for NP internalization.     

Cytokine production by co-cultures exposed to monodisperse amorphous silica nanoparticles: the role of size and surface area

The aim of this study was to test the influence of nanoparticle size and surface area (SA) on cytokine secretion by co-cultures of pulmonary epithelial cells (A549), macrophages (differentiated THP-1 cells) and endothelium cells (EA.hy926) in a two-compartment system. We used monodisperse amorphous silica nanoparticles (2, 16, 60 and 104 nm) at concentrations of 5 μg/cm2 cell culture SA or 10 cm2 particle SA/cm2. A549 and THP-1 cells were exposed to nanoparticles for 24h, in the presence of EA.hy926 cells cultured in an insert introduced above the bi-culture after 12h. Supernatants from both compartments were recovered and TNF-α, IL-6, IL-8 and MIP-1α were measured. Significant secretion of all cytokines was observed for the 2 nm particles at both concentrations and in both compartments. Larger particles of 60 nm induced significant cytokine secretion at the dose of 10 cm2 particle SA/cm2. The use of multiple cellular types showed that cytokine secretion in single cell cultures is amplified or mitigated in co-cultures. The release of pro-inflammatory mediators by endothelial cells not directly exposed to nanoparticles indicates a possible endothelium activation after inhalation of silica particles. This work shows the role of size and SA in cellular response to amorphous nanosilica.     

加压快速热解液相炭化焦的物理性质及CO2气化活性

以一种液相炭化焦(石油焦)为原料,在快速升温和热解压力为常压至3 MPa下制备了热解焦,主要考察了热解停留时间和热解压力对其失重、BET表面积和CO2气化活性的影响。结果表明：在加压快速热解条件下,随热解停留时间增加,液相炭化焦的失重率增加,BET表面积呈下降趋势,气化活性略微减小;随热解压力增加,液相炭化焦的失重率增加,BET表面积先增加后下降,气化活性略微变化,甚至基本不变;常压条件下液相炭化焦的气化活性明显高于加压条件下的气化活性。