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1.
神经酰胺与细胞凋亡   总被引:1,自引:0,他引:1  
神经酰胺与细胞凋亡叶珉王亚新(上海第二医科大学附属瑞金医院血液学研究所,上海200025)关键词神经酰胺细胞凋亡信号转导细胞凋亡为维持机体内环境稳定所必需,它与有丝分裂相互协调,共同调控胚胎发育、器官的发育和退化、免疫和造血等功能。研究发现,神经酰胺...  相似文献   

2.
神经酰胺与细胞凋亡   总被引:3,自引:0,他引:3       下载免费PDF全文
细胞凋亡 (apoptosis) 又称细胞的程序性死亡,参与机体许多生理和病理过程.近年来的研究表明细胞凋亡与鞘脂质代谢有密切的关系,鞘磷脂的水解产物神经酰胺作为脂质第二信使在诱导和抑制细胞凋亡中起着重要的作用.  相似文献   

3.
参照文献报道的方法建立了测定细胞神经酰胺的激酶催化法,以该法所做的标准曲线在一定浓度范围内有很好的线性关系。以UVB照射NIH 3T3细胞,可以使细胞神经酰胺的水平在1分钟之内迅速升高1.5倍以上,基本上达到了细胞所能生成神经酰胺的最高峰值。可细胞膜的外源性神经酰胺(C2-ceramide)作用于NIH 3T3细胞后能够导致细胞的凋亡和坏死,其凋亡率在一定剂量范围内随神经酰胺浓度的增加而增加;而在  相似文献   

4.
神经酰胺:细胞凋亡信号转号的第二信使分子   总被引:2,自引:0,他引:2  
神经酰胺是细胞凋亡信号调控中的一个第二信使因子,许多应激刺激能激活神经鞘磷脂循环产生神经酰胺诱导多种细胞体系发生凋亡。神经酰胺介导细胞凋亡的机理尚未完全明了,可能是通过多个下游靶分子包括CAPK,CAKK,PKC,SAPK/JNK,CPP32,Bcl-2以及Ras-RaclJNK/p38-K→GADD153信号传导链等作用于不同的信号转导途径而诱导细胞凋亡的。  相似文献   

5.
线粒体与细胞凋亡   总被引:1,自引:0,他引:1  
细胞凋亡是一种由基因控制的自主性死亡过程。近年来研究发现,线拉体在细胞凋亡过程中起重要作用,它可以通过改变膜通透性、释放凋亡活性物质等介导细胞凋亡。  相似文献   

6.
神经酰胺诱导小鼠皮层神经元凋亡   总被引:2,自引:2,他引:2  
本实验以原代培养的小鼠大脑皮层神经元为模型,观察了天然神经酰胺在神经元凋亡中的作用。从测定LDH漏出率、MTT代谢率、DNA凝胶电泳,Giemsa染色以及电镜观察等各个方面,探讨了神经酰胺对神经元的作用模式。研究发现,神经酰胺在500~1000nM浓度范围内,作用12h以上,即可诱导原代培养的皮层神经元凋亡,而且此作用具有时间依赖性和剂量依赖性。表明神经酰胺不仅对HL-60细胞有促凋亡的作用,对大脑皮层神经元同样具有促凋亡的作用。  相似文献   

7.
本研究探讨了外源性C2-神经酰胺诱导入结肠癌HT-29细胞凋亡中,线粒体膜间隙凋亡蛋白的释放机制.不同浓度C2-神经酰胺作用HT-29细胞,流式细胞仪检测线粒体膜电位(△ψm),线粒体/细胞液分离试剂盒分离亚细胞成分,聚丙烯酰胺凝胶电泳检测细胞色素C(Cytc)、高温必需蛋白A2(HtrA2)、线粒体源性半胱天冬氨酸蛋白酶第二活化因子(Smac)、凋亡抑制蛋白(XtAP)和半胱天冬氨酸蛋白酶-3(Caspase-3)蛋白表达水平.实验结果显示25和50μmol/L C2-神经酰胺作用细胞6h,△ψm即开始下降(P〈0.05),且环孢霉素能通过调节线粒体膜通透性转换孔抑制△ψm的下降.C2-神经酰胺对Cyt c,HtrA2和Smac总蛋白表达没有明显影响,但能诱导Cyt c,HtrA2和Smac从线粒体释放入细胞液中,并下调XIAP蛋白的表达及活化Caspase-3.在Caspase抑制剂存在下,C2-神经酰胺仍能诱导Cyt c和HtrA2从线粒体释放,但不能诱导Smac释放.因此认为C2-神经酰胺能通过线粒体凋亡通路诱导HT-29细胞凋亡,C2-神经酰胺诱导Cytc和HtrA2从线粒体的释放是Caspase非依赖性的,而Smac释放是Caspase依赖性的.  相似文献   

8.
本从神经酰胺的代谢,神经酰胺在神经鞘磷酯途径中充当第二信使,神经鞘磷酯途径连接SAPK/JNK(stress-activated Protein kinase/c-Jun N-terminal protein kinase)凋亡信号转导途径,神经酰胺介导的凋亡信号途径与ICE/Ced-3蛋白激酶的相互作用这四个方面阐述了神经酰胺在介导细胞凋亡中所起的中心作用,以利于了解促进,抑制凋亡的机制及其协同机制,为进一步的研究打好理论基础.  相似文献   

9.
以药物敏感型细胞株K562/S和耐药型细胞株K562/A02为对象.观察原癌基因Bcl-2的表达量在两种细胞中的差异,以及神经酰胺作为一个新的脂质第二信使诱导细胞凋亡的能力,并利用酪氨酸激酶抑制剂genistein,酪氨酸磷酸酯酶抑制剂vanadate,观察酪氨酸可逆磷酸化与细胞凋亡间的关系.结果显示:在K562/A02中Bcl-2的表达量明显高于K562/S;外源性神经酰胺能成功地诱导K562/S,K562/A02细胞凋亡,凋亡细胞具有典型的形态学改变和DNA“Ladder”形成,FCM检测出现凋亡细胞峰,但在同样的诱导条件下,K562/S细胞凋亡明显高于K562/A02细胞.FCM检测genistein能显著改变这两种细胞生长周期,但细胞阻滞于G2/M期,便对神经酰胺诱导的细胞凋亡无明显作用,vanadate单独对细胞地明显作用,但与神经酰胺共同作用能明显提高细胞凋亡率.以上结果表明在药物诱导的细胞调亡中Bcl-2基因起重要作用,神经酰胺能诱导K562/S和K562/A02细胞调亡.  相似文献   

10.
应激活化的蛋白激酶在神经酰胺介导细胞凋亡中的作用   总被引:1,自引:0,他引:1  
第二信使神经酰胺激活SAP/JNK,活化的SAPK/JNK导致AP-1转录因子磷酸化,AP-1刺激自身表达,增强自身活性,介导细胞凋亡,神经酰胺及其代谢产物鞘氨醇和鞘氨醇-1磷酸酯分别激活JNK-p38路径和ERK路径,调节细胞增殖,分化或凋亡。  相似文献   

11.
This study examined the impact of ceramide, an intracellular mediator of apoptosis, on the mitochondria to test the hypothesis that ceramide utilized p38 MAPK in the mitochondria to alter mitochondrial potential and induce apoptosis. The capacity of ceramide to adversely affect mitochondria was demonstrated by the significant loss of mitochondrial potential (ΔΨm), indicated by a J-aggregate fluorescent probe, after embryonic chick cardiomyocytes were treated with the cell permeable ceramide analogue C2-ceramide. p38 MAPK was identified in the mitochondrial fraction of the cell and p38 MAPK phosphorylation in this mitochondrial fraction of the cell occurred with ceramide treatment. In addition, SAPK phosphorylation and a decrease in ERK phosphorylation occurred in whole cell lysates after ceramide treatment. The p38 MAPK inhibitor SB 202190 but not the MEK inhibitor PD 98059 significantly inhibited ceramide-induced apoptosis and loss of ΔΨm. These data suggest that p38 MAPK is present in the mitochondria and its activation by ceramide indicates local signaling more directly coupled to the mitochondrial pathway in apoptosis. (Mol Cell Biochem 278: 39–51, 2005)  相似文献   

12.
We have previously seen that protein kinase C (PKC) epsilon induces neurite outgrowth and that PKCdelta and PKCtheta elicit apoptosis in neuroblastoma cells. In this study we investigate the effects of cell-permeable C(2)-ceramide on these events in SK-N-BE(2) neuroblastoma cells. C(2)-ceramide abolishes neurite formation induced by overexpression of PKCepsilon and, in cells overexpressing PKCdelta or PKCtheta, ceramide treatment leads to apoptosis. Exposure to C(2)-ceramide also suppressed neurite outgrowth induced by retinoic acid, but ceramide did not abrogate neurite induction by treatment with the ROCK inhibitor Y-27632, demonstrating that C(2)-ceramide is not a general inhibitor of neurite outgrowth. The neurite-suppressing effect occurs independently of cell-death. Furthermore, C(2)-ceramide relocated PKCepsilon and the isolated regulatory domain of PKCepsilon from the cytosol to the perinuclear region. In contrast, neither the localization of PKCdelta nor of PKCtheta was affected by C(2)-ceramide. Taken together, the data indicate that the neurite-inhibiting effect of C(2)-ceramide treatment may be caused by a re-localization of PKCepsilon and thus identify a functional consequence of ceramide effects on PKCepsilon localization.  相似文献   

13.
Sphingolipids are essential structural components of cellular membranes, playing prominent roles in signal transduction that governs cell proliferation, differentiation and apoptosis. Ceramides, a family of distinct molecular species characterized by various acyl chains, are synthesized de novo at the cytosolic side of the endoplasmic reticulum serving as precursors for the biosynthesis of sphingolipids in the Golgi. Recently, mitochondria emerged as an important intracellular compartment of sphingolipid metabolism. Thus, several sphingolipid-metabolizing enzymes were found to be associated with mitochondria, including neutral ceramidase, novel neutral sphingomyelinase, and (dihydro) ceramide synthase, an important ceramide-generating enzyme in de novo ceramide synthesis and recycling pathway. Mitochondrial dysfunction appears to be essential in tissue damage after brain ischemia/reperfusion (IR). Mitochondria are known to be involved in both the necrosis and apoptosis detected in animal models of ischemic stroke, and treatments that ameliorate tissue infarction were associated with better recovery of mitochondrial function. Although mitochondrial injury in stroke has been extensively studied and key mitochondrial functions affected by IR are mainly characterized, the nature of the molecule that causes loss of mitochondrial integrity and function remains obscure. Emerging data indicate a deregulation of ceramide metabolism in mitochondria damaged by IR suggesting that ceramides could play critical roles in cerebral IR-induced mitochondrial damage. This review will examine the experimental evidence supporting the key role of ceramides in mitochondrial dysfunction in cerebral IR and highlight potential targets for development of novel therapeutic approaches for stroke treatment.  相似文献   

14.
Mitochondrial Ceramide and the Induction of Apoptosis   总被引:11,自引:0,他引:11  
In most cell types, a key event in apoptosis is the release of proapoptotic intermembrane space proteins from mitochondria to the cytoplasm. In general, it is the release of these intermembrane space proteins that is responsible for the activation of caspases and DNases that are responsible for the execution of apoptosis. The mechanism for the increased permeability of the mitochondrial outer membrane during the induction phase of apoptosis is currently unknown and highly debated. This review will focus on one such proposed mechanism, namely, the formation of ceramide channels in the mitochondrial outer membrane. Ceramides are known to play a major regulatory role in apoptosis by inducing the release of proapoptotic proteins from the mitochondria. As mitochondria are known to contain the enzymes responsible for the synthesis and hydrolysis of ceramide, there exists a mechanism for regulating the level of ceramide in mitochondria. In addition, mitochondrial ceramide levels have been shown to be elevated prior to the induction phase of apoptosis. Ceramide has been shown to form large protein permeable channels in planar phospholipid and mitochondrial outer membranes. Thus, ceramide channels are good candidates for the pathway with which proapoptotic proteins are released from mitochondria during the induction phase of apoptosis.  相似文献   

15.
Nitric oxide and reactive oxygen species play a critical role in photoreceptor apoptosis. However, the exact molecular mechanisms triggered by oxidative stress in photoreceptor cell death remain undefined. Here, we demonstrate that the sphingolipid ceramide is the key mediator of oxidative stress-induced apoptosis in 661W retinal photoreceptor cells. Treatment of 661W cells with the nitric oxide donor, sodium nitroprusside, activates acid sphingomyelinase. As a result, sphingomyelin is hydrolysed, which leads to an increase in the concentration of ceramide. We also show that ceramide is responsible for the activation of the mitochondrial apoptotic pathway in 661W photoreceptor cells and subsequent activation of the caspase cascade. Furthermore, we show for the first time that ceramide is responsible for the increased Ca2+ levels in the mitochondria and cytosol that precedes activation of the calpain-mediated apoptotic pathway. Additionally, we provide evidence that ceramide also activates the endolysosomal protease cathepsin D pathway. In summary, our findings show that ceramide controls the cell death decisions in photoreceptor cells and highlight the relevance of acid sphingomyelinase as a potential therapeutic target for the treatment of retinal pathologies.  相似文献   

16.
凋亡诱导期,线粒体内神经酰胺水平升高,当每纳摩尔线粒体膜磷脂内含4~6皮摩尔神经酰胺时,神经酰胺即在线粒体外膜形成稳定的跨膜通道,从而使外膜通透性增加,线粒体膜间蛋白释放,启动细胞凋亡.神经酰胺通道只能在线粒体外膜形成,它是由神经酰胺柱组成的桶装结构,神经酰胺的反式双键具有增加通道的稳定性的作用.  相似文献   

17.
Ceramide and other sphingolipids in cellular responses   总被引:7,自引:0,他引:7  
Formerly considered to serve only as structural components, sphingolipids are emerging as an important group of signaling molecules involved in many cellular events, including cell growth, senescence, meiotic maturation, and cell death. They are also implicated in functions such as inflammation and the responses to heat shock and genotoxic stress. Defects in the metabolism of sphingolipids are related to various genetic disorders, and sphingolipids have the potential to serve as therapeutic agents for human diseases such as colon cancer and viral or bacterial infections. The best-studied member of this family, ceramide, which also serves as the structural back-bone for other sphingolipids, is an important mediator in multiple cellular signaling pathways. The metabolism and functions of sphingolipids are discussed in this review, with a focus on ceramide regulation in various cellular responses.  相似文献   

18.
Ceramide glycanase (CGase) activities have been detected in different human tumor cells (colon, carcinoma Colo-205; neuroblastoma, IMR-32; breast cancer lines, SKBr3 and MCF7). However, the level of enzymatic activity is lower in these cells compared to that present in other mammalian tissues reported before (Basu, M., Kelly, P., Girzadas, M. A., Li, Z., and Basu, S. Methods Enzymol. (in press)). The majority of CGase activity was found in the 100,000g soluble supernatant fraction isolated from all these cell lines and tissues. Using the soluble enzyme, the requirement for optimum CGase activity was found to be consistent with previous observations found for rat and rabbit tissues (Basu, M., Dastgheib, S., Girzadas, M. A., O'Donnell, P. H., Westervelt, C. W., Li, Z., Inokuchi, J. I., and Basu, S. (1998) Acta Pol. Biochim. 42:327). The CGase activities from both Colo-205 and IMR-32 cells are optimum at a protein to detergent ratio of one. All the mammalian CGases, including human cancer cells, show an optimum pH between 5.5 and 5.8 in sodium acetate buffer. The CGase activities from cancer cells are found to be cation-independent; however, mercury, zinc, and copper ions seem to inhibit the enzyme activity substantially in both tumor cells lines. The mercury ion inhibition of CGase activities from all different sources indicates a possible structural homology in the CGase proteins.Radiolabeled substrates, labeled at the sphingosine double bond or at the 3-position of sphingosine without modifying double bond of sphingosine were used in this investigation. Both were active substrates with all enzyme preparations isolated from different cancer cells (apparent Km, 500 M for nLcOse5[3H-DT]Cer and 350 M for GgOse4[sph-3-3H]Cer with Colo-205 enzyme). Structural analogues of ceramide and sphingosine (L-PPMP, L-PDMP, alkylamines, and Tamoxifen) inhibited cancer cell CGase activities in vitro.  相似文献   

19.
Ceramides are potent lipid second messengers that are involved in apoptotic and hypoxic/ischaemic neurone death. We investigated the role of mitochondria and the mitochondrial apoptosis pathway in ceramide-induced cell death using human D283 medulloblastoma cells with a reduced mitochondrial DNA copy number (rho- cells) and a corresponding defect in mitochondrial respiration. Treatment with the complex I inhibitor rotenone, C2- or C8-ceramide induced cell death in D283 control cells, while rho- cells were significantly protected. In contrast, activation of the mitochondrial apoptosis pathway by transient overexpression of the pro-apoptotic Bax protein or exposure to the kinase inhibitor staurosporine induced apoptosis to a similar extent in control and rho- cells. Overexpression of the antiapoptotic protein Bcl-xL failed to inhibit the toxic effect of C2-ceramide in D283 control cells, and no significant increase in caspase-3-like protease activity could be detected during the death process. Despite this, C2-ceramide induced significant chromatin condensation and cell shrinkage in D283 control cells, reminiscent of apoptosis. These morphological alterations were associated with the activation of calpains. Both apoptotic morphology and calpain activation were attenuated in rho- cells. Our data indicate that the apoptosis-inducing effect of C2-ceramide may require mitochondrial respiratory chain activity and can occur independently of the mitochondrial apoptosis pathway, but involves the activation of calpains.  相似文献   

20.
Kim JH  Han JS  Yoon YD 《Tissue & cell》1999,31(6):531-539
We have investigated the effects of ceramide on the progression of cell cycle and on apoptotic cell death in ovarian cultured granulosa cells. Rates of cellular proliferation were measured by immunocytochemical staining for proliferating cell nuclear antigen (PCNA) and flow cytometric cell cycle analysis. We also examined for morphological and biochemical signs of apoptosis. The PCNA expression was downregulated in a dose-dependent manner after treatment with C6-ceramide. Flow cytometric analysis demonstrated that the exposure of granulosa cells to C6-ceramide markedly decreased the population associated with G0/G1 DNA content and the reduction of cell numbers in G0/G1 phase was accompanied by the elevation of the A0 phase. The exposure of granulosa cells to exogenous C6-ceramide induced drastic morphological changes including cytoplasmic- or nuclear condensation and typical apoptotic DNA degradation. We also observed that phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator, significantly inhibited the ceramide-induced apoptosis. These results suggested that ceramide might block the progression of cell cycle at G0/G1 phase and as a consequence, granulosa cells would be committed to apoptosis. Our findings also indicated that down-regulation of the PKC activity might be involved in the ceramide-induced apoptosis in cultured granulosa cells.  相似文献   

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