p27~(Kip1)在永生化人神经前体细胞分化中的作用研究

目的:利用全反式视黄酸(all-trans retinoic acid,RA)诱导永生化的人神经前体细胞(immortalized human neural progenitor cells,hSN12W-TERTcells)分化,研究分化过程中细胞周期调节蛋白p27Kip1,p21Cip1,细胞周期蛋白激酶2(cyclin-dependent kinase2,cdk2)及细胞周期蛋白E(cyclinE)的变化,探讨永生化人神经前体细胞分化的相关分子机制。方法:取本课题组已经建立的永生化人神经前体细胞系hSN12W-TERT细胞(第12代)培养并给予1μmol/L RA诱导。在RA诱导的第3,7d观察细胞形态变化,用RT-PCR方法检测RA诱导前后hSN12W-TERT细胞p27Kip1,p21Cip1,cdk2及cyclinE mRNA的变化,用免疫细胞化学染色方法比较RA诱导前后p27Kip1蛋白表达的变化。结果:RA诱导第3d,hSN12W-TERT细胞比未经RA诱导的正常hSN12W-TERT细胞生长缓慢且形态发生改变,表现为胞体变小,突起延长增多。至RA诱导第7d时,hSN12W-TERT细胞形态变化更加明显,接近成熟神经元形态。RT-PCR结果表明,hSN12W-TERT细胞中p27Kip1mRNA的表达在RA诱导后明显增加,而p21Cip1mRNA的表达在RA诱导后略呈下降趋势。hSN12W-TERT细胞中cdk2、cyclinE的mRNA水平在RA诱导前后没有明显变化。免疫细胞化学染色结果显示,RA诱导第3d,hSN12W-TERT细胞p27Kip1的表达比未经RA诱导的正常hSN12W-TERT细胞明显增加(P0.05),RA诱导第7d,p27Kip1的表达进一步增加(P0.05)。结论:p27Kip1参与RA诱导的永生化人神经前体细胞生长阻滞和分化过程,p27Kip1可能在永生化人神经前体细胞的神经元分化过程中发挥重要作用;且RA诱导后p27Kip1蛋白含量的增加是通过转录水平调节的。     

p27~(Kip1)调控永生化人神经前体细胞分化的机制

目的研究p27Kip1在永生化人神经前体细胞分化中的作用,探讨神经前体细胞的分化机制。方法取本课题组已建立的永生化人神经前体细胞系hSN12W-TERT细胞(第12代)进行培养,在细胞进入对数生长期时给予1μmol/L全反式视黄酸(RA)诱导,重复诱导3次,每次均在诱导的第3、5、7天收集细胞,用流式细胞仪分析RA诱导第3天细胞周期的变化,用免疫印迹法检测RA诱导第3、5、7天p27Kip1、p21cip1细胞周期蛋白依赖激酶2(cdk2)及S期激酶相关蛋白2(skp2)的变化。结果流式细胞术结果显示,hSN12W-TERT细胞经1μmol/LRA诱导3d后,G0/G1期细胞的比例由77.25%上升至85.68%,而S期的比例由9.38%下降到8.57%。免疫印迹法结果显示,RA诱导第3天,hSN12W-TERT细胞p27Kip1蛋白表达比未经RA诱导的细胞增加,并在RA诱导第5天达到高峰(P0.05)。未经RA诱导的正常hSN12W-TERT细胞p21Cip1蛋白表达弱,RA诱导后p21Cip1蛋白的表达略呈下降趋势。RA诱导前后hSN12W-TERT细胞cdk2蛋白的表达变化不明显,但反映cdk2活性的磷酸化cdk2(p-cdk2)的表达在RA诱导后明显下降,同时,参与p27Kip1泛素降解途径的重要因子skp2的表达在RA诱导后明显下降。结论在RA诱导hSN12W-TERT细胞分化的过程中,p27Kip1通过抑制cdk2的活性而发挥促细胞分化的作用,且RA诱导后p27Kip1蛋白含量增加与其泛素降解途径被抑制密切相关。     

RXR激动剂通过抑制PKC激活对抗高糖诱导的大鼠血管平滑肌细胞增殖

 目的:探讨视黄醇类X受体 (RXR)激动剂对高糖诱导的大鼠主动脉平滑肌细胞(RASMCs)增殖的影响及其作用机制。方法:体外组织块干涸法培养RASMCs,以25 mmol/L葡萄糖干预,模拟糖尿病患者体内环境,通过WST-1法检测细胞增殖活性,BrdU插入法测定细胞DNA合成,流式细胞术检测细胞周期进程。用免疫印迹杂交方法检测细胞周期蛋白依赖激酶2(CDK2)、细胞周期蛋白依赖激酶抑制物p27Kip1的蛋白表达及蛋白激酶C (PKC)的磷酸化水平。结果:(1) 在高糖环境(葡萄糖终浓度为25 mmol/L)下,RASMCs的增殖活性、DNA合成速率及其在细胞周期S期的分布比例均显著增加;(2) 高糖显著增加RASMCs内CDK2蛋白的表达,但明显降低p27Kip1的蛋白表达水平;(3) RXR天然配体9-顺式维甲酸(9-cis-RA)可显著抑制高糖诱导的RASMCs增殖活性增强、DNA合成加速及RASMCs在细胞周期S期分布比例的增加幅度,且具有浓度依赖性;10-7mol/L浓度的SR11237(RXR特异性配体)与等浓度的9-cis-RA具有相似的抑制效应;(4) 9-cis-RA 和SR11237均可显著抑制高糖诱导的CDK2蛋白表达水平的增加幅度,同时上调高糖环境下p27Kip1蛋白的表达;(5) PKC抑制剂(PKC inhibitor peptide, 20 μmol/L)显著抑制高糖环境下RASMCs的增殖活性和CDK2蛋白的表达,但明显增加高糖条件下p27Kip1蛋白的表达;(6) 9-cis-RA 和SR11237可抑制高糖诱导的PKC蛋白磷酸化。结论: PKC的活化参与了高糖诱导下RASMCs的增殖过程。RXR激动剂通过抑制PKC活化对抗高糖诱导的血管平滑肌细胞增殖。     

p27Kip1反义寡核苷酸对B淋巴瘤细胞WEHI-231细胞周期的影响

目的　探讨p2 7Kip1在抗原受体介导的B淋巴瘤细胞WEHI- 2 31细胞周期停止信号中的作用。方法　用抗IgM抗体诱导WEHI- 2 31细胞细胞周期停止。用合成的p2 7Kip1反义寡核苷酸抑制p2 7Kip1基因的表达。采用流式细胞仪 ,分析细胞核的DNA含量和细胞周期的变化。用体外激酶实验检测Cdk2的活性 ,Westernblot检测Rb蛋白的磷酸化水平。结果　合成的p2 7Kip1反义寡核苷酸能阻断抗IgM抗体诱导的p2 7Kip1基因表达的上调。用p2 7Kip1反义寡核苷酸处理WEHI-2 31细胞 ,可恢复抗原受体交联引起的周期素依赖性激酶Cdk2活性的降低 ,以及Rb蛋白磷酸化水平的下降 ,并使细胞周期恢复运转。结论　p2 7Kip1可能在抗原受体信号介导的WEHI-2 31细胞的细胞周期停止中发挥主要作用     

幽门螺杆菌对SGC-7901细胞增殖凋亡及p27kipl表达的影响

目的 探讨幽门螺杆菌(Helicobacterpriori,Hp)对感染细胞增殖凋亡及细胞周期蛋白抑制因子p27kipl表达的影响.方法 不同浓度Hp国际标准株NCTC11637分别感染胃上皮细胞株SGC-7901,测定p27kipl蛋白及mRNA的表达、细胞增殖指数和凋亡率.结果 (1)Hp在3.4×104～1.9×105CFUml浓度时,SGC-7901的增殖指数随Hp浓度增高而显著增高,而在Hp≥14.8×106CFU/ml时明显降低;(2)Hp≥9.6×105CFU/ml时,细胞凋亡率呈浓度依赖性显著增高(P<0.01);(3)细胞p27kiplmRNA表达阳性率元显著变化,而p27kipl蛋白表达阳性率呈Hp浓度依赖性显著降低(P<0.05),与细胞凋亡率呈负相关.结论 Hp感染可直接导致胃上皮细胞增殖与凋亡的紊乱,影响细胞周期调控蛋白p27kipl的表达.     

P27(Kip1)的研究进展

本文主要综述了细胞周期依赖性激酶特异性抑制蛋白 P2 7(Kip1)的基因、蛋白分子特征 ,P2 7(Kip1)蛋白的晶体结构及其和周期素、周期素依赖性激酶的作用方式 ,从而对细胞周期产生的负调控作用。以及 P2 7(Kip1)蛋白水平的调节、亚细胞定位 ,P2 7(Kip1)与凋亡的关系、临床应用价值等     

干扰素诱导蛋白16对人脑血管外膜成纤维细胞增殖与迁移的影响及其机制

 目的：研究干扰素诱导蛋白16(IFI16)对人脑血管外膜成纤维细胞（HBVAFs）增殖与迁移的影响及其可能机制。方法：在HBVAFs中转染针对IFI16基因的小分子干扰 RNA (siRNA) 48 h后, 用2×106 U/L 干扰素-α（IFN-α）处理转染IFI16 siRNA细胞24 h。流式细胞术测定细胞周期,细胞划线法与Transwell法测定细胞迁移能力。应用 real-time PCR法和蛋白免疫印迹 (Western blotting) 法分别测定细胞中 IFI16、p53及p21 mRNA和蛋白表达水平的变化。结果：转染IFI16 siRNA后,HBVAFs中IFI16、p53及p21 mRNA和蛋白表达水平下调,增加了细胞G1/S期转换。IFN-α可诱导HBVAFs中IFI16、p53及p21mRNA和蛋白表达水平上调,同时抑制细胞G1/S期转换与细胞迁移,但在转染了IFI16 siRNA的HBVAFs中IFN-α的上述作用受到抑制。结论：IFI16表达可以抑制HBVAFs增殖和迁移,其机制可能与激活p53和p21的表达有关。     

慢病毒介导的重组p27^kip1对肾癌恶性表型影响

目的观察LV/p27^kip1慢病毒颗粒感染对肾癌细胞株786-0恶性表型影响及祼鼠皮下移植肿瘤的影响,以明确p27^kip1在肾癌中的生物学特性,期望为肾癌的预后评估及基因治疗策略提供实验依据。方法利用四质粒系统包装并纯化LV/p27^kip1慢病毒颗粒,对786-0细胞进行感染后分别进行Western Blot检测、细胞周期分析、细胞增殖测定、细胞杀伤率测定。选取BALB/C祼鼠,构建皮下移植瘤成功后注射LV/p27^kip1慢病毒,结束治疗后进行组织病理学检查及TUNEL检测。结果通过外源基因的导入,WesternBlot显示p27^kip1蛋白在感染后的786-0细胞中高表达,且跟随MOI值的增高而表达量相应增多;细胞周期分析表明外源性p27^kip1蛋白在786-0细胞高表达可抑制细胞由G1期向S期过渡;细胞增殖曲线提示感染后第72小时起细胞出现显著的数量下降,且随着MOI值的增加提高对细胞增殖的抑制;细胞杀伤性检测表明MOI=2、MOI=4、MOI=8组的LV/p27^kip1感染对细胞有显著杀伤作用,但影响效果无明确的规律;体内实验证实祼鼠皮下肿瘤在病毒的作用下出现了明显的坏死及凋亡。结论增加外源性p27^kip1表达可以阻滞肾癌细胞周期,抑制肿瘤细胞增殖,诱发凋亡。     

PDGF-BB对血管平滑肌细胞表型标志物表达的影响

目的:观察血小板源性生长因子BB(PDGF-BB)对血管平滑肌细胞(VSMCs)增殖及分化相关基因表达的影响,探讨其可能的机制。方法:分离体外培养的SD大鼠胸腹主动脉VSMCs,分为空白对照组和不同浓度PDGF-BB处理组。分别采用MTT法、流式细胞术和伤口愈合实验检测PDGF-BB对VSMCs增殖、细胞周期和迁移活性的影响;用W estern b lotting分析检测VSMCs表型标志物的表达;用免疫沉淀和免疫共沉淀分析检测Krüppel样因子4(KLF4)磷酸化及与其它转录因子的相互作用。结果:PDGF-BB促进VSMCs增殖和迁移;上调增殖相关蛋白PCNA的表达,下调增殖抑制蛋白p27、分化相关蛋白SM22α的表达。PDGF-BB诱导KLF4的表达和磷酸化,促进KLF4与NF-κB的相互作用,抑制KLF4与Sm ad3、HDAC2的结合。结论:PDGF-BB可能通过影响KLF4磷酸化及其与不同转录调节因子的相互作用而诱导VSMCs表型转化。     

氟伐他汀抑制大鼠血管平滑肌细胞迁移的机制

目的:研究氟伐他汀抑制血管紧张素Ⅱ(AngⅡ)与血小板源性生长因子-BB(PDGF-BB)诱导的大鼠血管平滑肌细胞(VSMCs)迁移的可能机制。方法:采用体外培养大鼠胸主动脉平滑肌细胞;用特异性单克隆磷酸化热休克蛋白27(phospho-HSP27)抗体的Western blotting检测HSP27的活性;用FITC-鬼笔环肽标记F-actin并在激光共聚焦显微镜下观察细胞骨架的形态变化;采用改良的Boyden微孔膜双槽法进行细胞迁移实验。结果:AngⅡ和PDGF-BB呈浓度依赖性诱导VSMCs的HSP27磷酸化,使VSMCs内F-actin数量明显增加,纵向平行排列,形成应力纤维丝,并促进细胞迁移。100μmol/L HSP27阻断剂槲皮素可阻抑AngⅡ、PDGF-BB刺激VSMCs后产生的应力纤维丝形成,对AngⅡ、PDGF-BB诱导的VSMCs迁移的抑制率分别为55.3%和53.6%,P0.01。氟伐他汀抑制AngⅡ和PDGF-BB诱导的HSP27磷酸化,并有量效关系,抑制作用在10-5mol/L时最显著,最大抑制率分别为42.1%和58.5%,P0.01。结论:氟伐他汀可能通过抑制HSP27磷酸化影响VSMCs的迁移。     

氟伐他汀对大鼠血管平滑肌细胞迁移的影响及其机制

目的：探讨氟伐他汀(Flu)对血小板源生长因子(PDGF-BB)和内皮素-1(ET-1)诱导的血管平滑肌细胞(VSMCs)迁移的影响及其机制。 方法： VSMCs源于8周龄自发性高血压大鼠(SHR)的胸主动脉，组织块外生法体外培养VSMCs，采用改良的Boyden微孔膜双槽法测定细胞迁移，荧光染料Fura-2/AM法测定细胞内游离钙离子浓度(［Ca2+］i)。 结果： (1) PDGF-BB和ET-1可诱导VSMCs迁移，作用峰值浓度分别为10 μg/L和10-7 mol/L。Flu(10-9-10-5mol/L)呈浓度依赖性抑制上述物质诱导的细胞迁移，10-5mol/L Flu对PDGF-BB和ET-1诱导的细胞迁移的抑制率达86.67％以上。 (2)PDGF-BB和ET-1促进［Ca2+］i升高(P<0.05)，峰值浓度分别为PDGF-BB 10 μg/L和ET-1 10-8mol/L。 (3) Flu明显抑制PDGF-BB和ET-1诱发的［Ca2+］i升高，峰抑制率分别为86.76％和65.32％。 结论： Flu可抑制PDGF-BB和ET-1诱导的VSMCs迁移，Flu抑制［Ca2+］i的升高可能是它抑制VSMCs迁移的机制之一。     

Combined examination of p27(Kip1), p21(Waf1/Cip1) and p53 expression allows precise estimation of prognosis in patients with gastric carcinoma

AIMS: In order to estimate the prognostic values of p27(Kip1), p21(Waf1/Cip1), and p53, alone and in combination, we investigated immunohistochemically the expression of p27(Kip1), p21(Waf1/Cip1), and p53 proteins in gastric carcinomas. METHODS AND RESULTS: The expression of p27(Kip1), p21(Waf1/Cip1), and p53 was immunohistochemically examined in 140 gastric carcinomas. Positive expression of p27(Kip1) and p21(Waf1/Cip1) correlated significantly with a favourable prognosis (P < 0.05), whereas, positive expression of p53 tended to correlate with poor prognosis. Multivariate survival analysis revealed that TNM stage of tumour (P < 0.001), lymph node state (P=0.005), and p27(Kip1) expression (P=0.006) were independent prognostic factors. A striking stratification of mortality rate was found when patients were divided into four groups according to the expression of p21(Waf1/Cip1) and p27(Kip1). The mortality rate was higher in patients with both p21(Waf1/Cip1)- and p27(Kip1)-negative gastric carcinoma than in patients with one or both positive carcinomas (P < 0.01). In addition, if the four p21(Waf1/Cip1)/p27(Kip1) groups were compared based on p53 status, p53+ cases tended to have a higher mortality rate than p53- cases. CONCLUSION: Our results suggest that low expression of both p27(Kip1) and p21(Waf1/Cip1), could be useful as markers of poorer prognosis, and the combined examination of p27(Kip1), p21(Waf1/Cip1) and p53 expression allows reliable estimation of prognosis for patients with gastric carcinoma.     

The cyclin-dependent kinase inhibitors p27Kip1 and p21Cip1 are not essential in T cell anergy

Recent evidence suggests that the cyclin-dependent kinase (Cdk) inhibitors p27Kip1 and p21Cip1 are important factors in T cell anergy, but it has remained unclear whether anergy can be induced in their absence. We therefore induced anergy by stimulation of purified T cells from wild-type, p21Cip1-/-, and p27Kip1-/- mice with anti-CD3 antibodies. Anergic wild-type T cells were arrested in the G1 phase of the cell cycle with a high p27Kip1 protein level and low Cdk2 activity. In p27-/- and p21-/- T cells, the pattern of protein expression was preserved, but Cdk2 activity was increased. To confirm the in vivo relevance of these data, anergy was induced by repeated injection of mice with staphylococcal enterotoxin B (SEB), which leads to partial deletion of the responsive Vbeta8+ T cell population and anergy in the remaining T cells. p21-/- mice and wild-type mice reacted similarly to this treatment. p27-/- mice showed reduced deletion of SEB-responsive T cells, but persisting T cells were anergic. These data indicate that other cell cycle regulators contribute to the cell cycle arrest of anergic T cells, as neither Cdk inhibitor is required for the induction of anergy.     

notch1基因对人胶质瘤U251细胞增殖和周期的影响

目的：探讨notch1基因对人胶质瘤U251细胞增殖和周期的影响。方法: 体外构建notch1-shRNA和pNL-NICD/EGFP慢病毒表达载体,采用RT-PCR和Western blotting方法行notch1沉默和高表达notch1胞内段的效果检测,MTT法和PI单染流式细胞术分析notch1对细胞增殖和细胞周期的影响。结果：notch1-shRNA慢病毒表达载体能有效下调notch1表达,而pNL-NICD/EGFP慢病毒表达载体能有效增加NICD的表达。notch1基因表达下调的细胞其细胞增殖能力受到明显抑制(P<0.01),并引起细胞G1期阻滞(P<0.01), S期减少(P<0.01);在NICD表达增加的细胞其增殖能力明显增强(P<0.01),且引起细胞G1期减少(P<0.05),S期增加(P<0.01)。结论: notch1基因与人胶质瘤U251细胞的增殖能力和周期密切相关,有望成为治疗胶质瘤的靶点。     

阿魏酸钠对血管平滑肌细胞热休克蛋白27磷酸化的影响

目的： 研究阿魏酸钠对血管紧张素II（angiotensinⅡ,AngII）与血小板源性生长因子-BB（platelet derived growth factor-BB,PDGF-BB）诱导的血管平滑肌细胞（vascular smooth muscle cells,VSMCs）中热休克蛋白27（heat shock protein 27,HSP27）磷酸化的影响。方法：采用体外培养大鼠胸主动脉平滑肌细胞；用特异性的单克隆phospho-HSP27抗体的蛋白印迹法（Western blotting）检测HSP27的活性。结果：阿魏酸钠以剂量依赖性方式抑制AngII和PDGF-BB诱导的HSP27磷酸化，在10-4 mol/L〖JP2〗时抑制作用最明显，最大抑制率分别为39.0%（P<0.05）和56.8%（P<0.01）。结论：阿魏酸钠具有明显抑制由AngII和PDGF-BB诱导的VSMCs HSP27磷酸化的作用。     

Gastrodin inhibits cell proliferation in vascular smooth muscle cells and attenuates neointima formation in vivo

Vascular smooth muscle cell (VSMC) proliferation plays a critical role in the development of vascular diseases. In the present study, we tested the efficacy and the mechanisms of action of gastrodin, a bioactive component of the Chinese herb Gastrodia elata Bl, in relation to platelet-derived growth factor-BB (PDGF-BB)-dependent cell proliferation and neointima formation after acute vascular injury. Cell experiments were performed with VSMCs isolated from rat aortas. WST and BrdU incorporation assays were used to evaluate VSMC proliferation. Eight-week-old C57BL/6?mice were used for the animal experiments. Gastrodin (150?mg/kg/day) was administered in the animal chow for 14?days, and the mice were subjected to wire injury of the left carotid artery. Our data demonstrated that gastrodin attenuated the VSMC proliferation induced by PDGF-BB, as assessed by WST assay and BrdU incorporation. Gastrodin influenced the S-phase entry of VSMCs and stabilised p27Kip1 expression. In addition, pre-incubation with sinomenine prior to PDGF-BB stimulation led to increased smooth muscle-specific gene expression, thereby inhibiting VSMC dedifferentiation. Gastrodin treatment also reduced the intimal area and the number of PCNA-positive cells. Furthermore, PDGF-BB-induced phosphorylation of ERK1/2, p38 MAPK, Akt and GSK3β was suppressed by gastrodin. Our results suggest that gastrodin can inhibit VSMC proliferation and attenuate neointimal hyperplasia in response to vascular injury. Furthermore, the ERK1/2, p38 MAPK and Akt/GSK3β signalling pathways were found to be involved in the effects of gastrodin.     

The ability of antigen,but not interleukin-2, to promote n-butyrate-induced T helper 1 cell anergy is associated with increased expression and altered association patterns of cyclin-dependent kinase inhibitors

The ability of the cell cycle inhibitor n-butyrate to induce T helper 1 (Th1) cell anergy is dependent upon its ability to block the cell cycle progression of activated Th1 cells in G1. Results reported here show that although both interleukin (IL)-2 and antigen (Ag) push Th1 cells into G1 where they are blocked by n-butyrate, only the Ag-activated Th1 cells demonstrate functional anergy once the n-butyrate has been removed from the culture. Because n-butyrate-induced Th1 cell anergy has been linked to increased expression of the cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1, mechanistic experiments focused on the role of these inhibitors. It was found that when Th1 cells were reincubated in Ag-stimulated secondary cultures, the Th1 cells previously exposed to Ag and n-butyrate (anergic Th1 cells) demonstrated a cumulative increase in p21Cip1 and p27Kip1 when compared with Th1 cells previously exposed to recombinant (r)IL-2 and n-butyrate (non-anergic Th1 cells). p27Kip1 in the anergic Th1 cells from the secondary cultures was associated with cyclin-dependent kinases (cdks). In contrast, p21Cip1 in the anergic Th1 cells, although present at high levels, did not associate significantly with cdks, suggesting that p21Cip1 may target some other protein in the anergic Th1 cells. Taken together, these findings suggest that Th1 cell exposure to Ag and n-butyrate, rather than IL-2 and n-butyrate, is needed to induce the cumulative increase in p21Cip1 and p27Kip1 that is associated with the proliferative unresponsiveness in anergic Th1 cells. In addition, p21Cip1 may inhibit proliferation in the anergic Th1 cells by some mechanism other than suppression of cdks that is unique to the induction of Th1 cell anergy.     

G1 arrest and high expression of cyclin kinase and apoptosis inhibitors in accumulated activated/memory phenotype CD4+ cells of older lupus mice

A general characteristic of lupus-prone mice (and humans) is the expedited accumulation of large numbers of presumably self-reactive activated/memory phenotype T cells. The mechanism by which these cells escape apoptosis has not been defined. We used activated/memory phenotype CD4⁺ cells from male BXSB mice with early-life severe lupus-like disease to investigate cell cycle status and apoptosis susceptibility, and to determine the role of corresponding genes in survival of these cells. In vitro acridine orange staining indicated that most of the rapidly accumulating memory phenotype CD4⁺ T cells of 4-month-old male BXSB mice are G1 arrested. Long-term bromodeoxyuridine in vivo labeling also showed that with advanced age, there was a shift of the CD4⁺ CD44^hi male cells from predominantly cycling to predominantly noncycling. Moreover, the CD4⁺ CD44^hi cells of older males were refractory to anti-CD3-induced proliferation and apoptosis. Using a multiprobe RNase protection assay encompassing riboprobe panels for cell cycle and apoptosis-related genes, we found that these cells exhibited high expression of certain members of the Ink4 (p18^Ink4C) and Cip/Kip (p21^Cip1) families of cyclin kinase inhibitors as well as of the apoptosis-inhibiting Bcl-x_L gene. Western blot analysis confirmed increased levels of Bcl-x_L and p21^Cip1, and also identified increases in another cyclin kinase inhibitor, p27^Kip1. We propose that in autoimmunity, self-reactive CD4⁺ cells are subjected to successive rounds of activation/division that eventually lead to a build-up in cyclin-dependent kinase inhibitors. Once high levels of such inhibitors are reached, they cause refractoriness to further activation, impaired cell cycle entry and resistance to apoptosis, a situation akin to replicative senescence.     

麝香保心丸对内皮素-1诱导原代培养的人脐动脉血管平滑肌细胞增殖的影响

目的:观察麝香保心丸(SXBXW)对内皮素-1(ET-1)诱导原代培养的人脐动脉血管平滑肌细胞(VSMCs)增殖作用的影响。方法:建立ET-1刺激原代培养人脐动脉VSMCs增殖的细胞模型,设对照组、ET-1组、ET-1+SXBXW0.25g/L组、ET-1+SXBXW0.5g/L组、ET-1+SXBXW1.0g/L组和ET-1+SXBXW2.0g/L组,采用MTT法测定ET-1和SXBXW对细胞增殖的影响;用台盼蓝拒染和乳酸脱氢酶检测方法观察不同浓度的SXBXW对VSMCs的毒性作用;用流式细胞术观察ET-1和SXBXW对VSMCs增殖周期的影响。结果:与对照组相比,ET-1可显著促进VSMCs的增殖,一定剂量的SXBXW能够有效地抑制ET-1诱导的VSMCs细胞增殖,呈剂量依赖性;SXBXW抑制细胞增殖,但对活细胞数目和乳酸脱氢酶释放量均没有影响,提示对VSMCs无毒性作用。ET-1能够刺激VSMCs从G1期进入S期,从而促进细胞增殖,而SXBXW能抑制这一作用。结论:SXBXW能够有效抑制ET-1诱导的VSMCs增殖作用,其作用机制可能与其抑制细胞周期从G1期进入S期有关。