D类细胞周期素在细胞周期中的作用

细胞周期进程由周期性表达的细胞周期素和细胞周期素信号性激酶推动完成,CyclinD在G1期中期开始表达,是最早合成的细胞周期素,它与Cdk4或Cdk6形成的活性复合物,不仅可促进pRb的磷酸化,也可隔离P27对cyclinE-Cdk2活性的抑制,使细胞顺利越过G1期进入S期,除此之外,cyclinD过度表达还可抑制细胞增殖,在细胞分化和衰老过程中发挥重要作用。     

位点特异DNA甲基化调控细胞周期素D1基因

DNA甲基化是基因表达调控的重要方式,一般被认为以CpG岛形式发挥作用;近年的研究表明,位点特异的DNA甲基化以元件(cis-regulatory element)的形式在生物微进化以及基因精细调控中发挥重要作用。我们的研究结果显示,曲古抑菌素A (trichostatin A,TSA)导致细胞周期蛋白D1基因表达下调,以及其核心启动子的+65到+77之间的两段串联CpG序列发生DNA甲基化。报告基因结果显示,由细胞周期素D1核心启动子片段驱动的报告基因活性在TSA处理后下降到原来0.12,而前段(A)突变与后段(B)突变时,报告基因活性分别下降到原来1/7.6与1/8.36,双突变则下降到原来1/7.51。对于CMV启动子嵌合15 bp片段驱动的报告基因活性,野生型、A、B与AB双突变型报告基因活性分别下降1/1.48、1/1.17、1/1.51以及1/1.21。体外甲基化研究结果显示,与对照组相比,M.SssⅠ处理组的启动子活性中,野生型活性下降到原来1/8 800,A突变型活性下降到原来1/2 700,B突变型活性下降到原来1/4 156,双突变型活性下降到原来1/6 222。应...     

血管紧张素II诱导培养的成年大鼠心肌细胞凋亡

研究血管紧张素Ⅱ（ＡｎｇⅡ）诱导培养的成年大鼠心肌细胞（ＡＲＶＭｓ）凋亡。酶灌流消化法分离培养ＡＲＶＭｓ,不同处理后,光镜观察形态改变,琼脂糖凝胶电泳定性分析ＤＮＡ降解程度。结果发现培养的ＡＲＶＭｓ经ＡｎｇⅡ１０μｍｏｌ／Ｌ处理４８ｈ后,大部分细胞变圆,胞浆浓缩;电泳显示核酸断裂片段“梯形”结构,上述改变在７２ｈ更为明显。上述作用可被氯沙坦、维拉帕米和ｓｔａｕｒｏｓｐｏｒｉｎｅ所取消。这表明Ａｎｇ     

细胞周期素与细胞周期的调控

本综述了不同细胞周期素的分子结构和对细胞周期的调控作用,在细胞周期的不同时期,周期素与P34^cdc2及其相关激酶相作用,产生特定的激酶活性,使细胞通过细胞周期特定的调控点,周期素的累积与降解对细胞周期进程的调控起着重要的作用。     

细胞周期素G1和G2在膀胱癌中的表达及临床意义

目的探讨细胞周期素G1和G2在膀胱移行细胞癌（尿路上皮癌）中的表达及临床意义。方法收集武汉大学人民医院病理科2000-2006年有完整临床和病理资料的膀胱移行细胞癌存档蜡块50例和5例癌旁组织,采用免疫组织化学S-P法检测50例膀胱移行细胞癌和5例癌旁组织中细胞周期素G1和G2的表达水平。采用HPIAS-1000高清晰度彩色病理图文报告管理系统,对细胞周期素G1和G2的表达进行定量分析,并用SPSS11.5软件对各组免疫组织化学反应阳性颗粒的平均光密度、阳性面积率做单因素方差分析和SNK（q）检验。结果细胞周期素G1在膀胱移行细胞癌中呈高表达,癌旁组织中呈低表达。而细胞周期素G2在膀胱移行细胞癌中呈低表达,癌旁组织中呈高表达。膀胱移行细胞癌与癌旁组织相比,差异有显著性（P〈0.05）。随着移行细胞癌组织中细胞周期素G1表达的增高,周期素G2的表达却显著下降,两者呈显著负相关（P〈0.01）。结论细胞周期素G1和G2在膀胱移行细胞癌与癌旁组织中对细胞周期调控和/或DNA修复起了重要作用,并参与了诱导细胞凋亡的过程。     

新生大鼠心室成纤维细胞条件培养液的促心肌细胞肥大作用

利用新生大鼠心室成纤维细胞条件培养液孵育心肌细胞,证实成纤维细胞条件培养液能明显增大心肌细胞的表面积,增加心肌细胞的蛋白含量和「＾３Ｈ」－亮氨酸「＾３Ｈ」－Ｌｅｕ）的掺入,上述作用以第３天的条件培养液作用最强,具有剂量依赖性。ＥＴＡ受体拮抗剂ＢＱ１２３能部分阻断成纤维细胞条件培养液促进心肌细胞肥大的作用,而ＡＴ１受体拮抗剂ＣＶ１１９７４和α－肾上腺素受体拮抗剂ｒｅｇｉｔｉｎ却无此效果。结果提示：成     

细胞周期素A在血管瘤组织中的表达及临床意义

目的 探讨细胞周期素A在血管瘤中的表达及与血管瘤发生、发展的关系。方法收集武汉大学人民医院病理科1996—2001年皮肤毛细血管瘤存档蜡块49例,所有标本常规HE染色和免疫组织化学SP法检测增殖细胞核抗原（proliferating cell nuclear antigen,PCNA）,按Mulliken分类标准并结合PCNA的表达进行分组;然后采用免疫组织化学SP法和原位杂交检测49例皮肤毛细血管瘤增生期、退化期及正常皮肤组织中细胞周期素A的表达水平,并结合检测Ⅷ因子相关抗原的表达证实血管瘤组织中表达细胞周期素A的细胞的确是血管瘤内皮细胞,对免疫组织化学结果采用HPIAS-1000高清晰度彩色病理图文报告管理系统对细胞周期素A的表达进行定量分析。并用SPSS11．5软件对各组免疫组织化学反应阳性颗粒的平均光密度、阳性面积率做单因素方差分析和SNK（q）检验。结果增生期血管瘤内皮细胞中细胞周期素A高表达,退化期呈低表达。经q检验,增生期组与退化期组之间、增生期组与正常皮肤组之间,细胞周期素A的平均光密度及阳性面积率有显著性差异（P〈0．01）,退化期组与正常皮肤组之间平均光密度及阳性面积率的差异无显著性（P〉0．05）。结论细胞周期素A在增生期血管瘤组织中的过度表达使细胞周期紊乱,是增生期血管瘤内皮细胞不断分裂增生。     

培养成年大鼠心肌细胞存活的形态标志

目的：通过探寻增加培养成年大鼠心肌细胞存活率以及防止再分化的方法,揭示培养成年大鼠心肌细胞存活的形态标志。方法：采用Langendorff系统灌流心脏,胶原酶消化法分离成年大鼠心肌细胞,分3组进行细胞培养：①基础培养液＋凋亡抑制剂;②基础培养液＋5%胎牛血清;③基础培养液＋5%胎牛血清＋凋亡抑制剂。结果：①培养前3天杆状心肌细胞比例逐渐降低,无血清培养组比血清培养组降低程度大。培养前3天凋亡率逐渐升高,无血清培养组比血清培养组凋亡率高,加入凋亡抑制剂对凋亡率无影响。②有血清培养2~3天的成年大鼠心肌细胞闰盘部位伸出伪足,促使细胞贴壁生长;当培养至第6天时,细胞侧面也伸展出贴壁的伪足,细胞丧失杆状形态,横纹消失。而无血清培养的细胞无伪足生成,随着培养时间增加,细胞末端变圆钝,横纹变模糊。凋亡抑制剂对伪足形成率无影响。③培养存活的成年大鼠心肌细胞骨架重排,发生再分化。④血清培养组细胞胞内核间距离随着培养时间的增加而减小,无血清培养组则保持不变。结论：成年大鼠心肌细胞培养至第2~3天时,闰盘部位形成伪足是细胞存活的形态标志,加入血清是伪足形成的必要条件。     

血管紧张素Ⅱ诱导培养的成年大鼠心肌细胞凋亡

研究血管紧张素Ⅱ(AngⅡ)诱导培养的成年大鼠心肌细胞(adult rat ventricular myocytes,ARVMs)凋亡.酶灌流消化法分离培养ARVMs,不同处理后,光镜观察形态改变,琼脂糖凝胶电泳定性分析DNA降解程度.结果发现培养的ARVMs经AngⅡ10μmol/L处理48 h后,大部分细胞变圆,胞浆浓缩;电泳显示核酸断裂片段"梯形"结构,上述改变在72 h更为明显.上述作用可被氯沙坦、维拉帕米和staurosporine所取消.这表明AngⅡ由AT1受体介导诱导培养的ARVMs凋亡,细胞内钙升高和PKC激活起重要作用.     

细胞周期素G1、G2在皮肤血管瘤组织中的表达及意义

目的探讨细胞周期素G1、G2与血管瘤发生发展及退化的关系。方法采用免疫组织化学S-P法对50例血管瘤和5例正常皮肤组织检测细胞周期素G1、G2的表达;对所获得的检测结果进行图像分析处理。结果增生期血管瘤内皮细胞胞浆或胞核内cyclin G1呈强阳性表达,退化期血管瘤内皮细胞胞浆内cyclin G1无表达;增生期血管瘤内皮细胞胞浆内无cyclin G2表达,退化期血管瘤内皮细胞胞浆内cyclin G2呈强阳性表达。增生期组与退化期组、正常皮肤组分别相比,细胞周期素G,阳性表达差异有显著性（P〈0．05）,退化期组与增生期组、正常皮肤组之间,细胞周期素G2的阳性表达差异有显著性（P〈0．05）。结论细胞周期素G1、G2在血管瘤发生、发展及退化中起着重要作用。     

Muscle Differentiation in Cultured Pineal Body Cells of Neonatal Rats

Dissociated cells of pineal bodies of new-born rats were cultured to see what cell types would be differentiated during culture in vitro for about 4 weeks. In early stages of culture, about 10 days after inoculation, flattened cells with piliform processes, small round cells and small bubbling cells were distinguishable in the cultures. After about 2 weeks, neuronal cells with axon-like processes and multinuclear muscle-like cells were differentiated. On further culture, the latter cells differentiated into mature striated myotubes. The developmental origin of myotube formed in cell cultures of pineal body is discussed.     

Kainate-Induced Apoptosis in Cultured Murine Cerebellar Granule Cells Elevates Expression of the Cell Cycle Gene Cyclin D1

Abstract: Recent evidence suggests that neuronal apoptosis is the consequence of an inappropriate reentry into the cell cycle. Expression of the cell cycle gene cyclin D1, a G1-phase cell cycle regulator, was examined in primary cultures of murine cerebellar granule cells (CGCs) during kainate (KA)-mediated apoptosis. Using cultures of CGCs, we found that a 24-h exposure to KA (1–3,000 µ M ) induced a concentration-dependent cell death with neurons exhibiting characteristic apoptotic morphology and extensive labeling using the terminal transferase-mediated nick end-DNA labeling (TUNEL) method. KA induced a time- and concentration-dependent increase in expression of cyclin D1 as determined by immunocytochemistry and western blot analysis. KA-induced apoptosis and cyclin D1 expression exhibited a similar concentration dependence and were significantly attenuated by the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (50 µ M ), indicating a KA receptor-mediated effect. Here we present evidence for the first time that KA-induced apoptosis in cultured CGCs involves the induction of cyclin D1, suggesting its involvement in excitotoxic receptor-mediated apoptosis.     

CyclinD1在鲍温病中的表达

目的:探讨cyclinD1(细胞周期蛋白D1)在鲍温病皮肤组织中的表达及其临床意义。方法:采用免疫组化S-P法观察16例鲍温病标本中cyclinD1的表达模式。结果:正常人皮肤组织中,cyclinD1阳性细胞主要分布在基底层及毛囊漏斗部的基底层细胞上。在16例鲍温病标本中14例细胞核内cyclinD1过度表达,阳性细胞分布于肿瘤组织。结论:cyclinD1的异常表达可能与鲍温病的发生相关。     

糜酶基因在转染的乳鼠心脏组织细胞中的表达

糜酶基因在转染的乳鼠心脏组织细胞中的表达何泉陈兰英（中国医学科学院、中国协和医科大学,心血管病研究所、阜外心血管病医院,北京１０００３７）ＴｈｅＨｕｍａｎＨｅａｒｔＣｈｙｍａｓｅＧｅｎｅＥｘｐｒｅｓｓｉｏｎｉｎＣｕｌｔｕｒｅｄＮｅｏｎａｔａｌＲａｔＨ...     

Carbachol-induced Suppression of Contraction Rhythm in Spontaneously Beating Cultured Cardiac Myocytes From Neonatal Rats

Nitric oxide (NO) and reactive oxygen species (ROS) are known to play various functional and pathophysiological roles as an intracellular messenger in the heart. In this study, we investigated whether the increased production of NO and/or ROS was involved in the cholinergic regulation of rhythmic contraction in spontaneously beating cultured cardiac myocytes from neonatal rats. Exposure of cultures to carbachol, an agonist of muscarinic acetylcholine receptors (mAchR), produced a dose-dependent decrease in the beat rate of cultured cardiac myocytes, and such a effect was significantly attenuated by pre-treatment with an NOS inhibitor, as well as an NO scavenger. In addition, exposure to an NO donor (SNAP) also decreased the beat rate dose-dependently. Carbachol- or SNAP-induced suppression of the contraction rhythm was significantly attenuated by co-treatment with 5-hydroxydecanoate (5-HD). In contrast, treatment with diazoxide decreased the beat rate dose-dependently. Carbachol treatment increased the intensity of 2',7'-dichlorodihydrofluorescein fluorescence, suggesting that the production of ROS was enhanced by the treatment. In addition, the carbachol- or diazoxide-induced suppression of contraction rhythm was attenuated by co-treatment with 2-mercaptopropionyl glycine, a scavenger of ROS. The present study has suggested that the mAchR-NO-mitoK ATP -ROS pathway is a factor responsible for carbachol-induced suppression of contraction rhythm in cultured cardiac myocytes.     

Cyclin D1在膀胱癌中的表达及意义

目的探讨细胞因子CyclinD1在膀胱癌中的表达及临床意义。方法收集武汉大学人民医院病理科2000-2006年有完整临床和病理资料的膀胱癌存档蜡块50例和5例癌旁组织,采用免疫组织化学S-P法检测50例膀胱癌和5例癌旁组织中CyclinD1的表达水平,分析了CyclinD1与临床分期,病理分级的关系。采用HPIAS-1000高清晰度彩色病理图文报告管理系统,对CyclinD1的表达进行定量分析,并用SPSS13.0软件对各组免疫组织化学反应阳性颗粒的平均光密度、阳性面积率做单因素方差分析和SNK(q)检验。结果 CyclinD1在膀胱癌中呈高表达,癌旁组织中呈低表达,差异有显著性(P<0.05)。图像分析结果显示:膀胱癌与癌旁组织之间,CyclinD1的平均光密度及阳性面积率有显著性差异(P<0.05),经统计学分析,CyclinD1表达与膀胱癌病理分级临床分期无显著性差异(P>0.05)。结论 CyclinD1在膀胱癌中的异常表达可能参与膀胱癌的发生、发展过程。     

Effect of Daunorubicin on Subcellular Pools of Glutathione in Cultured Heart Cells from Neonatal Rats

Alterations in cellular GSH and its compartmentation were investigated as a possible mechanism of toxicity of the anthracycline derivative daunorubicin in neonatal heart cells. Cultured beating heart cells from neonatal rats were exposed to daunorubicin at therapeutically relevant concentrations and the resulting changes in cellular GSH as well as cytosolic and mitochondrial pools of GSH were determined. Toxicity was estimated as an increased permeability of the plasma membrane to cytosolic enzymes, e.g., lactate dehydrogenase.

Control heart cells were found to contain 12.2 ± 1.8 nmolesGSH/IO⁶ cells. Daunorubicin causedarapid initial decrease followed by a transient increase in cellular GSH. The extent of the latter increase was dependent on the concentration of daunorubicin. High concentrations of daunorubicin gave only a slight increase followed by a pronounced decrease in cellular GSH.

By applying a digitonin-based method the effect of daunorubicin on the cytosolic and mitochondrial pools of GSH were separated. The concentration of cytosolic and mitochondrial reduced GSH was estimated to be 89 ± 1.5nmoles, 10 cells and 3.3 ± 0.6 nmoles/10⁶ cells. respectively. The results indicate that daunorubicin caused a decrease of cytosolic GSH and. after a short lag period. a release of lactate dehydrogenase. No decrease of mitochondrial GSH occurred under these conditions indicating that daunorubicin influences selectively cytosolic GSH.

No lipid peroxidation products were detected in DRB-treated cells under conditions when lactate dehydrogenase was released. Likewise, addition of the iron-chelator desferrioxamin did not influence the release of lactate dehydrogenase. whereas dithiothreitol offered partial protection.

The results provide support for an oxidative mechanism in which the decrease in the cytosolic pool of GSH may be the causative factor of daunorubicin-induced toxicity. This decrease in GSH may affect the cytosolic NADPH and various redox groups on proteins, thereby altering the permeability of the plasma membrane and finally causing cell damage.     

Fluctuations of Contraction Rhythm During Simulated Ischemia/Reperfusion in Cultured Cardiac Myocytes from Neonatal Rats

Cardiac ischemia results in a rapid decrease of intracellular pH and in the rise of intracellular Ca 2+ , changes that have been shown to reduce intercellular communication via gap junctions (GJ) between cardiac myocytes. Ischemia also results in electrical instability probably caused by the reduced GJ permeability contributing to an increased vulnerability to arrhythmias. This study aims at elucidating whether the fluctuations of contraction rhythm of spontaneously beating cardiac myocytes in culture changes during simulated ischemia/reperfusion. The coefficient of variation (CV) of contraction intervals, reflecting the fluctuation of contraction rhythm, increased significantly during simulated ischemia/reperfusion. However, the contraction rhythm of the cardiac myocytes in an aggregate remained synchronized during simulated ischemia/reperfusion. In contrast, pharmacological blockade of GJ with 12-doxyl stearic acid, a blocker of GJ permeability, resulted in the de-synchronization of contraction rhythm and in an increase in the CV of contraction intervals in normoxic conditions. The present findings lead to the suggestion that GJ remained open during simulated ischemia/reperfusion, and that a mechanism other than electrical uncoupling between myocytes contributed to the observed increase in the fluctuation of beating rhythm during ischemia.