肺纤维化大鼠上皮细胞凋亡及Bcl-xl和Bid动态变化

目的 探讨肺纤维化大鼠中Bcl-2家族部分蛋白介导的线粒体途径引起上皮细胞凋亡的动态变化及相关关系.方法 选取SD大鼠48只,随机分为4组:空白对照组(24只)、模型7d组(8只)、模型14 d组(8只)、模型28 d组(8只).应用博莱霉素(5 mg/kg)气管内注入建立实验性大鼠肺纤维化模型,空白对照组注入等量生理盐水,各组动物于第7、14、28天随机处死8只,取肺组织采用HE染色观察病理变化,TUNEL法检测肺组织细胞凋亡,RT-PCR和免疫组化法分别检测肺组织Bid、Bcl-xl mRNA以及蛋白的表达.结果 实验性大鼠肺纤维化发病过程中,呈现典型的肺泡炎(7 d)、肺泡炎与纤维化并存(14 d)及稳定的肺纤维化(28 d)等表现;同时间段模型组肺组织细胞凋亡指数、Bid mRNA及蛋白表达均显著高于空白对照组(P＜0.01),Bcl- xl mRNA及蛋白表达显著低于空白对照组(P＜0.01);模型组细胞凋亡与Bid蛋白及mRNA从第7天开始逐步升高,第28天达最高峰,Bid mRNA与细胞凋亡指数呈正相关(r=0.8275,t =7.937 5,P＜0.01);模型组Bcl-xl蛋白与Bcl-xl mRNA表达在第7天开始下降,第28天达最低峰,Bcl-xl mRNA与细胞凋亡指数呈负相关(r=-0.633 8,t=-4.489,P＜0.01); Bcl-xl mRNA与Bid mRNA无明显相关性(r=-0.3869,t=-2.2986,P＞0.05).结论 细胞凋亡在肺纤维形成中起重要作用,肺纤维化细胞凋亡可能与Bcl-2家族蛋白的表达失衡有关.     

c-Jun NH2-terminal kinase-induced proteasomal degradation of c-FLIPL/S and Bcl2 sensitize prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine

Tetrandrine, a constituent of Chinese herb Stephania tetrandra, causes cell death in prostate cancer, but the molecular mechanisms leading to apoptosis is not known. Here we demonstrated that tetrandrine selectively inhibits the growth of prostate cancer PC3 and DU145 cells compared to normal prostate epithelial PWR-1E cells. Tetrandrine-induced cell death in prostate cancer cells is caused by reactive oxygen species (ROS)-mediated activation of c-Jun NH₂-terminal kinase (JNK1/2). JNK1/2-mediated proteasomal degradation of c-FLIP_L/S and Bcl₂ proteins are key events in the sensitization of prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine. Tetrandrine-induced JNK1/2 activation caused the translocation of Bax to mitochondria by disrupting its association with Bcl₂ which was accompanied by collapse of mitochondrial membrane potential (MMP), cytosolic release of cytochrome c and Smac, and apoptotic cell death. Additionally, tetrandrine-induced JNK1/2 activation increased the phosphorylation of Bcl₂ at Ser70 and facilitated its degradation via the ubiquitin-mediated proteasomal pathway. In parallel, tetrandrine-mediated ROS generation also caused the induction of ligand-independent Fas-mediated apoptosis by activating procaspase-8 and Bid cleavage. Inhibition of procaspase-8 activation attenuated the cleavage of Bid, loss of MMP and caspase-3 activation suggest that tetrandrine-induced Fas-mediated apoptosis is associated with the mitochondrial pathway. Furthermore, most of the signaling effects of tetrandrine on apoptosis were significantly attenuated in the presence of antioxidant N-acetyl-l-cysteine, thereby confirming the involvement of ROS in these events. In conclusion, the results of the present study indicate that tetrandrine-induced apoptosis in prostate cancer cells is initiated by ROS generation and that both intrinsic and extrinsic pathway contributes to cell death.     

Intracellular signaling in the induction of apoptosis in a human breast cancer cell line by water extract of Mekabu

Background We previously reported that water extract of Mekabu, a kind of seaweed, induced apoptosis in a human breast cancer cell line. In the present study we investigated intracellular signaling in apoptosis, with a focus on caspases.Methods Mekabu extract, obtained with ultrapure water, was used to induce apoptosis in a human breast cancer cell line, MDA-MB231, and DNA fractionation was investigated by flow cytometry and electrophoresis. In addition, using the caspase detection kit Caspa Tag, activation of caspases 3, 6, 8, and 9 was observed under a fluorescence microscope. Furthermore, using antibodies to caspases 3, 8, 9, and Bid, we conducted a protein analysis by Western blotting to determine the activation of these substances.Results Obvious ladder formation demonstrating DNA fractionation was seen, confirming that Mekabu extract induced apoptosis. In the fluorescence microscope observations, activation of caspases 3, 6, and 8, but not caspase 9, was seen. Activated caspases 3 and 8 were detected in the Western blotting analysis, but no proteins of activated caspase 9 or Bid were detected.Conclusion Mekabu extract activates caspases 3, 6, and 8 and contributes to intracellular signaling to induce apoptosis in a human breast cancer cell line. This signaling is not via the mitochondria.     

Regulation and Pathological Role of Bid in Ischemic Acute Kidney Injury

Bid, a BH3-only member of the Bcl-2 family proteins, is most abundantly expressed in the kidneys. Recent research has shown Bid activation in renal tubular cells in vitro following ATP-depletion and hypoxic injury, and also in vivo during renal ischemia-reperfusion in rats and mice. Importantly, Bid-deficient mice are resistant to ischemic kidney injury. Targeting Bid may therefore offer a new strategy for the treatment of acute renal failure associated with ischemia-reperfusion.     

Molecular mechanisms involved in the adaptive response to cadmium-induced apoptosis in human myelomonocytic lymphoma U937 cells

We examined the molecular mechanisms involved in the adaptive response to cadmium (Cd)-induced apoptosis in human myelomonocytic lymphoma U937 cells. When U937 cells were treated with 50 μM cadmium chloride (CdCl₂) for 12 h, significant apoptosis occurred. This was associated with an increase in intracellular reactive oxygen species (ROS), sustained phosphorylation of JNK, activation of caspase-3, a decrease in Mcl-1 (anti-apoptotic Bcl-2 proteins), and increases in Bim, Noxa and tBid (a pro-apoptotic protein under the Bcl-2 family). No apoptosis occurred when the cells were treated with 1 μM CdCl₂ for 72 h. However, pretreatment with low-dose CdCl₂ dramatically altered the sensitivity of the cells to 50 μM CdCl₂ with inhibition of apoptosis. Concomitantly, there were significant decreases in the generation of intracellular ROS and the activation of JNK. Pretreatment with 1 μM CdCl₂ also attenuated the decrease in Mcl-1 and the increases in Bim, Noxa and tBid induced by 50 μM CdCl₂. In conclusion, pretreatment with low-dose Cd inhibited apoptosis induced by high-dose Cd. The mechanism involves inhibition of intracellular ROS generation and JNK activation, and modulating the balance between the expression of Mcl-1 and its binding partners, Bim, Noxa and tBid.     

细胞色素C及相关细胞凋亡蛋白、基因在原发性肝癌组织表达的临床意义

目的观察外源性凋亡通路中Caspase8和Bid及内源性凋亡通路中Bcl-2、Bax、细胞色素C（Cyt-C）和Cas-pase9在50例原发性肝细胞癌（肝癌组）及30例正常肝组织（对照组）中的表达,并分析其与病理分期、肿瘤分化程度和淋巴结转移的关系。方法应用免疫组织化学方法检测Bax表达,应用核酸原位分子杂交方法检测Caspase8、Bid、Bcl-2、Cyt-C和Caspase9表达。结果 Caspase8表达强度与对照组比较呈升高趋势（P〈0.05）,阳性表达率组间差异未见统计学意义（P〉0.05）。Bid阳性表达率与对照组比较呈下降趋势（P〈0.01）,表达强度两组间差异未见统计学意义（P〉0.05）。Bcl-2阳性表达率和表达强度较对照组均明显下降（P〈0.01）,Bax阳性表达率和表达强度较对照组均下降（P〈0.05和P〈0.01）。Cyt-C和Caspase9的阳性表达率和表达强度两组间比较差异均未见统计学意义（P〉0.05）。高、中分化肝癌组Cyt-C阳性表达率均明显高于低分化肝癌组（P〈0.05和P〈0.01）,但其与病理分级和淋巴结转移未见相关性（P〉0.05）。Caspase8、Bid、Bcl-2、Bax和Caspase9在不同病理分级、肿瘤分化程度和淋巴结转移组中表达差异均未见统计学意义（P〉0.05）。结论在肝癌发生发展过程中,早期外源性凋亡通路发挥促凋亡活性,而随着肿瘤分化程度的降低,内源性凋亡通路发挥抗凋亡活性,且Cyt-C的表达调节应该是一晚期事件。     

Mechanisms of Andrographolide‐Induced Platelet Apoptosis in Human Platelets: Regulatory Roles of the Extrinsic Apoptotic Pathway

Andrographolide, a novel nuclear factor‐κB (NF‐κB) inhibitor, is isolated from the leaves of Andrographis paniculata. Platelet activation is relevant to a variety of coronary heart diseases. Our recent studies revealed that andrographolide possesses potent antiplatelet activity by inhibition of the p38 MAPK/^●HO‐NF‐κB‐ERK2 cascade. Although platelets are anucleated cells, apoptotic machinery apparatus recently has been found to regulate platelet activation and limit platelet lifespan. Therefore, we further investigated the regulatory effects of andrographolide on platelet apoptotic events. In this study, apoptotic signaling events for caspase‐3, ‐8, and Bid were time (10–60 min)‐ and dose (25–100 μΜ)‐dependently activated by andrographolide in human platelets. Andrographolide could also disrupt mitrochondrial membrane potential. In addition, caspase‐8 inhibitor (z‐IETD‐fmk, 50 μΜ) was found to reverse andrographolide‐induced caspase‐8 activation, whereas the antagonistic anti‐Fas receptor (ZB4, 500 ng/mL) and anti‐tumor necrosis factor‐R1 (H398, 10 µg/mL) monoclonal antibodies did not. In conclusion, this study for the first time demonstrated that andrographolide might limit platelet lifespan by initiating the caspase‐8‐dependent extrinsic apoptotic pathway, in spite of no direct evidence that death receptors are involved in this process proved. Overall, the various medicinal properties of andrographolide suggest its potential value in treating patients with thromboembolic disorders. Copyright © 2012 John Wiley & Sons, Ltd.     

"监理延伸服务"在医院建设中的探索

我国自1988年开始,在建设领域实行了建设工程监理制度,这是工程建设领域管理体制的重大改革.文章通过实施医院监理业务,对监理管理模式进行创新研究.     

CD40 stimulation of B-cell chronic lymphocytic leukaemia cells enhances the anti-apoptotic profile, but also Bid expression and cells remain susceptible to autologous cytotoxic T-lymphocyte attack

To enhance the poor antigen-presenting capacity of B-cell chronic lymphocytic leukaemia (B-CLL), CD40 triggering has been considered as an active immunotherapy. However, CD40 stimulation also has an anti-apoptotic effect and may further impair the dysregulated response of B-CLL to apoptotic stimuli. Therefore, we measured the expression of virtually all regulators of apoptosis before and after CD40 stimulation. These findings were correlated with sensitivity for chemotherapy- and death-receptor-induced apoptosis and T-cell-mediated killing. CD40 stimulation enhanced the constitutive anti-apoptotic profile of B-CLL cells by upregulation of Bcl-xL and Bfl-1 and downregulation of the BH3-only protein Harakiri. Unexpectedly, the BH3-only protein Bid was strongly induced. Functionally, CD40-stimulated B-CLL cells became resistant to drug-induced apoptosis and, despite upregulation of CD95 and Bid, were not sensitive to CD95L. In contrast, autologous T cell killing, triggered by loading CLL cells with viral (CMV) peptides, was very efficient both before and after CD40 stimulation. Upon CTL interaction, CLL targets underwent mitochondrial depolarization and caspase-3 activation. Thus, despite an increased anti-apoptotic profile, CD40 triggered B-CLL cells remain excellent targets for resident cytotoxic T cells. These data support therapeutic exploitation of CD40 stimulation in B-CLL, provided that a strong CTL component is induced.     

Upon Drug-Induced Apoptosis Expression of Prostate-apoptosis-response-gene-4 Promotes Cleavage of Caspase-8, Bid and Mitochondrial Release of Cytochrome c

Par-4 functions as a tumor suppressor antagonizing the transforming capacity and the resistance of malignant cells towards apoptotic stimuli. After demonstrating that par-4 promotes apoptosis by activating signaling of the intrinsic pathway of apoptosis, we hypothesized that par-4 also impacts on key molecules of the extrinsic pathway without the requirement of a receptor/ligand interaction. Here, we provide first evidence, that expression of par-4 increases cleavage of caspase-8, truncation of Bid and its translocation to the mitochondria, resulting in an augmentation of cytochrome c and AIF efflux into the cytosol, effects par-4-positive cells are able to retain to a higher extent than par-4-negative cells upon inhibition of caspase-3 activation.