Human Mast Cell Proteome Reveals Unique Lineage,Putative Functions,and Structural Basis for Cell Ablation

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Apoptosis and the expression of Bax and Bcl-2 in hyperplasia and adenocarcinoma of the uterine endometrium

BACKGROUND: Apoptosis plays a crucial role in carcinogenesis in various tumours. This study was designed to investigate the occurrence of apoptosis and the expression of Bcl-2 and Bax proteins in endometrial tumours of corpus uteri. METHODS: Endometrial tissues were obtained from 20 patients with endometrioid adenocarcinoma, 16 patients with endometrial hyperplasia, and 4 patients with myoma uteri (which were used as controls). The occurrence of apoptosis was examined by using molecular biochemical techniques. The expression of Bcl-2 and Bax proteins was also investigated using immunohistochemical staining with appropriate antibodies. RESULTS: The labelling of DNA in situ indicated that apoptotic cells were sporadically seen in postmenopausal endometrium (5.2 +/- 2.1, n = 4) and endometrial hyperplasia without atypia (2.6 +/- 0.5, n = 9). In contrast, labelled cells were detected in atypical endometrial hyperplasia (15.9 +/- 2.2, n = 7), and their numbers increased intensely in adenocarcinoma (29.3 +/- 3.7, n = 20). Autoradiographic analysis revealed DNA laddering in many cases of carcinoma. Bcl-2 was highly immunopositive in hyperplasia without atypia (36.2 +/- 6.5%, n = 9), but was decreased in the atypical endometrial hyperplasia (16.3 +/- 4.8%, n = 7). Large fractions of the carcinoma (6.3 +/- 1.8%, n = 20) and normal endometrium (2.8 +/- 1.4%, n = 4) were immunonegative or slightly immunopositive to Bcl-2. In contrast, Bax immunoreactivity was more frequent and stronger in adenocarcinoma (43.6 +/- 4.1%, n = 20) than that in normal endometrium (17.6 +/- 6.7%, n = 4) and hyperplasia (7.2 +/- 2.2%, n = 16). CONCLUSIONS: These results suggest that cells in hyperplasia expressing Bcl-2 might have prolonged survival ability. Neoplastic cells in adenocarcinoma might show apoptosis in association with a decreased expression of Bcl-2 and an increased expression of Bax. Therefore, the frequency of apoptosis and the expression of Bcl-2 and Bax might be correlated with carcinogenesis in the uterine endometrium of humans.     

Bcl-2 delays macrophage engulfment of human B cells induced to undergo apoptosis

The capacity to be recognized and engulfed by phagocytes is an important characteristic of cells dying by apoptosis. Phagocytosis of apoptotic cells occurs rapidly in vivo, probably prior to plasma membrane breakdown. While the molecular mechanisms mediating phagocytosis of apoptotic cells are beginning to be defined, little is yet known of the relationship between the cell-death program itself and the surface changes on the dying cells that signal for engulfment. Here, we investigate to what extent the apoptosis repressor Bcl-2 can modulate the recognition and phagocytosis of human B cells exposed to triggers of apoptosis. Burkitt lymphoma (BL)-derived, Bcl-2⁻ B cells were induced into apoptosis either by the Ca²⁺-ionophore ionomycin or by the inhibitor of protein synthesis cycloheximide. Apoptotic BL cells, but not viable BL cells, were recognized and phagocytosed by monocyte-derived macrophages. bcl-2-transfected BL populations showed a reduced capacity both to undergo apoptosis in response to these inducing agents and to interact with macrophages. Like their Bcl-2⁻ counterparts, Bcl-2⁺ BL cells interacted with macrophages only after activation of their apoptotic program as assessed by changes in nuclear morphology. These results demonstrate not only that continued protein synthesis in B cells undergoing apoptosis is not essential for their recognition by macrophages, but also that macrophage recognition of apoptotic B cells cannot be uncoupled from the cell-death program that is controlled by Bcl-2. In this respect, the behavior of B cells contrasts markedly with that of neutrophils in which Bcl-2 has been reported to inhibit apoptosis without affecting phagocytic clearance (Lagasse and Weissman, J. Exp. Med. 1994. 179: 1047).     

鲨鱼软骨制剂通过下调Bcl-2诱导K562细胞凋亡

目的探讨鲨鱼软骨制剂(SCP)诱导人红白血病细胞系(K562)凋亡的作用机制。方法以不同浓度SCP加入体外培养的K562细胞中,用MTT比色法检测细胞存活率;Hoechst33342/PI荧光染色,荧光显微镜分析凋亡细胞百分率;流式细胞术进行细胞凋亡定量;免疫细胞化学染色法检测Bcl-2蛋白的表达。结果SCP明显抑制K562细胞生长,IC50值为1mg/ml以下;荧光显微镜下可见50%以上细胞为凋亡细胞的形态学改变;免疫细胞化学检测显示SCP诱导细胞凋亡过程中Bcl-2表达明显降低。结论SCP诱导K562细胞凋亡,可能与下调Bcl-2表达有关。     

丙酸睾酮对大鼠胸腺细胞凋亡及胸腺中Bcl-2、Bax表达的影响

目的探讨丙酸睾酮在大鼠胸腺退化过程中的作用及其对大鼠胸腺中Bcl-2和Bax表达的影响。方法雄性大鼠去势后给予丙酸睾酮皮下注射,分别于注射后第1、4、7天取材,用半薄切片甲苯胺蓝染色检测胸腺细胞凋亡情况,免疫组织化学法检测胸腺组织中Bcl-2和Bax的表达情况,采用t检验进行统计学处理。结果丙酸睾酮处理组大鼠胸腺组织中可发现较多的凋亡细胞和凋亡小体;去势组大鼠胸腺组织中Bcl-2表达量明显高于假手术组（P〈0.001）,丙酸睾酮处理后Bcl-2表达量明显减少（P〈0.001）;而Bax的表达正好相反,去势组大鼠胸腺组织中Bax表达量明显低于假手术组（P〈0.001）,给予丙酸睾酮后Bax表达量明显增加（P〈0.001）;结论丙酸睾酮可诱导大鼠胸腺细胞凋亡,并抑制大鼠胸腺组织中Bcl-2的表达,促进Bax的表达。     

粉防己碱对缺血-再灌注损伤大鼠心肌细胞凋亡及Bcl-2/Bax蛋白表达的影响

目的探讨粉防己碱对缺血-再灌注损伤大鼠心肌细胞凋亡及Bcl-2/Bax蛋白表达的影响。方法结扎大鼠左冠状动脉前降支（LAD）30min后松开,再灌注24h建立心肌缺血-再灌注损伤模型。将48只雄性SD大鼠随机分为：假手术组（Sham组）,缺血-再灌注损伤组（IRI组）,粉防己碱预处理组（Tet组）。再灌注结束后检测血清肌酸激酶同工酶MB（CK-MB）和心肌梗死范围（IS/AAR,%）。应用原位末端标记法（TUNEL法）检测各组凋亡细胞,计算凋亡指数（AI）,应用免疫组化法检测心肌Bcl-2、Bax蛋白表达,计算Bcl-2/Bax值,进行组间比较。结果与IRI组相比,Tet可明显降低CK-MB值（976.57±160.69）vs（1910.38±221.10）U/L,P〈0.01,减小心肌IS/AAR%,（23.28±4.38）%vs（43.76±6.30）%,P〈0.01。与IRI组比较,粉防己碱预处理可显著减少心肌细胞凋亡,AI显著降低（8.62±2.45%vs19.36±5.28%,P〈0.01）。粉防己碱预处理使Bcl-2表达增加,Bax表达下降,Bcl-2/Bax值显著升高（P〈0.01）。结论粉防己碱能明显抑制缺血-再灌注损伤引起的心肌细胞凋亡,其作用机制可能与促进Bcl-2蛋白表达,减少Bax蛋白表达、升高Bcl-2/Bax比值有关。     

脓毒症大鼠心肌细胞凋亡与Bcl-2蛋白表达关系的研究

目的研究脓毒症大鼠心肌细胞凋亡的变化及其与Bcl-2蛋白表达的关系,探讨Bcl-2在心肌细胞凋亡中的作用。方法以盲肠结扎穿刺法复制脓毒症大鼠模型,以电镜和TUNEL法检测其心肌细胞凋亡变化,用免疫组化方法检测Bcl-2和蛋白的表达。用SPSS10.0软件完成统计分析。结果一定时间内脓毒症大鼠心肌细胞凋亡率均明显高于正常对照组和假手术对照组（P均〈0.05）,Bcl-2蛋白表达阳性数均较正常对照组和假手术组明显降低（P均〈0.05）,其变化与TUNEL法检测凋亡的结果趋势相反。结论细胞凋亡可能是脓毒症中心肌损害的机制之一,Bcl-2基因的改变或许可以作为脓毒症病情改变的标志,可利用它们对脓毒症进行干预,以改善脓毒症的预后。     

Growth hormone prevents human monocytic cells from Fas-mediated apoptosis by up-regulating Bcl-2 expression

Apoptosis and particularly Fas-mediated apoptosis has been proposed to play a key role in controlling monocyte homeostasis. We and others have documented the regulatory function of human growth hormone (hGH) on monocytic cells, which prompted us to investigate the role of hGH on their response to Fas antigen cross-linking. Using human promonocytic U937 cells constitutively producing hGH upon gene transfer and human primary monocytes cultured in the presence of recombinant hGH, we demonstrated that hGH diminished Fas-mediated cell death by enhancing the expression of the antiapoptotic oncoprotein Bcl-2 as well as the level of bcl-2α mRNA. In parallel, we established that overexpression of Bcl-2 through gene transfer into normal U937 cells also diminished Fas-induced apoptosis. Further, as a result of Bcl-2 overexpression, we found that hGH greatly depressed Fas-induced activation of the cysteine protease caspase-3 (CPP32), which in turn affected the cleavage of poly(ADP-ribose) polymerase. Altogether, these data provide evidence that hGH mediates its protective effect through a Bcl-2-dependent pathway, clearly a crucial step in enhanced survival of monocytic cells exposed to Fas-induced death.     

Urocortin调控Bcl-2家族与大鼠缺氧/复氧心肌细胞凋亡

目的观察神经肽Urocortin对大鼠缺氧/复氧心肌细胞Bcl-2及相关基因mRNA表达和细胞凋亡的影响。方法培养新生大鼠的心肌细胞并缺氧/复氧处理,用RT-PCR检测Bcl-2、Bax、Bcl-xL、Bad mRNA表达,TUNEL法检测细胞凋亡。结果Urocortin治疗组Bcl-2的mRNA表达与缺氧/复氧组比较明显增加(P<0.05),Bax的表达明显下降(P<0.05),Bcl-xL、Bad mRNA表达无明显改变(P>0.05)。Urocortin治疗组凋亡细胞率与缺氧/复氧组比较减少(P<0.05)。结论Urocortin调节心肌细胞Bcl-2家族基因转录下凋促凋亡基因Bax表达,上调抑凋亡基因Bcl-2使Bcl-2/Bax比值增加。这可能是Urocortin抗大鼠缺氧/复氧心肌细胞凋亡的机制之一。     

哮喘豚鼠嗜酸细胞Bcl-2和Bax mRNA表达及意义

目的:观察Bcl-2及Bax mRNA表达与嗜酸粒细胞（Eos）凋亡的关系,探讨其在哮喘发病中的作用。方法:健康豚鼠随机分为正常组、哮喘组,卵蛋白致敏激发制作哮喘模型,检测支气管灌洗液（BALF）中低密度EoS（HEos）及正常密度Eos（NEos）细胞凋亡,原位杂交及RT-PCR法检测Bcl-2及Bax mRNA表达。结果:哮喘组EoS显著高于正常组,以HEos为著（P<0.01）;Eos凋亡率明显低于正常组（P<0.01）。哮喘组不同密度Eos表达Bcl-2 mRNA明显增加,而Eos表达Bax mRNA明显减少。结论:哮喘时Eos存在凋亡抑制,这是哮喘时Eos增多的原因之一,哮喘豚鼠BALF Eos表达Bcl-2增加,表达Bax减少,表明Bcl-2及Bax可通过调节Eos凋亡参与哮喘发病。     

Apoptosis and the B Cell Response to Antigen

The primary B cell response to T cell dependent antigens comprises two pathways of differentiation; one resulting in formation of foci of antibody forming cells in the extrafollicular regions of secondary lymphoid organs and the other giving rise to germinal centers within the follicles. Foci of antibody forming cells are detectable for only a limited time, before involuting due to apoptosis of the plasma cells. Similarly in the germinal center, regulation of cell number, selection of high affinity variants generated by somatic hypermutation, and the resolution of the germinal center itself all involve the death of unwanted B cells. In this review, we describe recent experiments which have allowed determination of the role of certain forms of apoptosis in the B cell response to antigen.     

Rho prevents apoptosis through Bcl-2 expression: Implications for interleukin-2 receptor signal transduction

Here we describe a Rho-mediated apoptosis suppression pathway driven by Bcl-2 expression in the interleukin (IL)-4- or IL-2-dependent murine T cell line TS1αβ. IL-2, but not IL-4, induces Bcl-2 expression through RhoA activation which is inhibited by the specific Rho family inhibitor, Clostridium difficile Toxin B, as well as by a dominant negative RhoA mutant. Using transient transfections of RhoA mutants tagged with the vesicular stomatitis virus glycoprotein, we show that a constitutively active RhoA mutant induces Bcl-2 expression and prevents apoptosis upon IL-4 withdrawal. Finally, we have identified the signaling pathway involved together with RhoA in Bcl-2 induction and show compelling evidence for the implication of phosphatidylinositol 3 kinase and protein kinase C.     

Bcl-2表达与小鼠腹腔巨噬细胞凋亡的关系

利用免疫荧光技术和激光扫描共聚焦显微镜（共焦镜）技术检测了地塞米松介导小鼠腹腔巨噬细胞凋亡时调亡抑制基因Ｂｃｌ－２表达的时空变化。结果显示,免疫荧光技术和共焦镜技术可对细胞内的蛋白表达作定量和定位检测,凋巨噬细胞内Ｂｃｌ－２逐渐减少,核中Ｂｃｌ－２相对量逐渐减少,胞浆中Ｂｃｌ－２相对量逐渐增多,Ｂｃｌ－２表达和地塞米松介导的巨噬细胞凋亡呈极显著负相关。结果表明,地塞米松介导巨噬细胞凋亡时,凋亡抑制     

Molecular Mechanisms for Apoptosis Induced by Signaling Through the B Cell Antigen Receptor

Although the B cell antigen receptor (BOR) transmits survival and activation signals, BCR ligation can induce apoptosis in both immature and mature B cells. BCR-mediated apoptosis is suggested to play a role in self-tolerance by deleting self-reactive B cells. Generation of an apoptotic signal through BCR appears to depend on the composition of the higher order BCR complex and is suggested to occur outside the plasma membrane microdomains, termed lipid rafts. During BCR-mediated apoptosis, mitochondrial dysfunction is induced and is essential for apoptosis, probably by activating both caspases, cysteine proteases that play a central role in apoptosis, and caspase-independent effectors for apoptosis. Although signaling pathways for apoptosis are not yet fully defined in BCR-mediated apoptosis, expression of the proto-oncogene product c-Myc is enhanced upon BCR ligation, and c-Myc appears to mediate BCR ligation-induced apoptosis by causing mitochondrial dysfunction, suggesting that BCR-mediated apoptosis is a form of Myc-induced apoptosis.     

CD4<Superscript>+</Superscript> T Cells Downregulate Bcl-2 in Germinal Centers

Germinal centers (GCs) are the main site of T cell-dependent antibody responses. Upon antigen challenge, GCs comprise mostly B cells undergoing proliferation, somatic hypermutation and antigen-affinity selection. GC B cells down-modulate the expression of Bcl-2 protein and are highly sensitive to apoptosis to eliminate autoreactive or low-affinity cells. Bcl-2 is still expressed in a few GC cells, whose identity remains unclear. To address this issue, we examined by confocal microscopy the expression of Bcl-2 by different GC lymphocyte subsets in hyperplastic tonsils. We found that the vast majority of Bcl-2⁺ GC cells are T lymphocytes. Conversely, while in the mantle zone and in the interfollicular areas T cells are almost exclusively Bcl-2⁺, in the GC, most T lymphocytes are Bcl-2⁻. In addition, most of the CD4⁺ GC T cells are Bcl-2⁻, while nearly 100% of the CD8⁺ GC T cells are Bcl-2⁺. The Bcl-2 downregulation by both B and CD4⁺ T GC cells supports the concept that these two subsets may undergo a selection process in this microenvironment.     

Expression of Bcl-2 and Survivin in uterine cervical carcinogenesis and correlation between the expression and infection of HPV_(16/18)

Carcinomaofthecervixisthesecondleading causeofdeathamongwomenworldwide.Each year,anestimated500000casesarenewlydiag nosed[1].Manystudiesshowedinfectionofhu manpapillomavirus(HPV)wasoneofthemost importantetiologicfactorsforcervicalcarcinoma[24].Morethan95%ofallcervicalcarcinomas havebeenfoundtobeassociatedwithHPV(ma inlytypes16and18)[5].Thestudiesinmolec ularoncologyrecentlyshowedthatitresultedin occurrenceanddevelopmentofcervicalcarcinomasthatcarcinogenicfactorsmadeproto oncogene activatean…