粘着斑激酶活性对气道上皮细胞增殖的影响

目的:研究粘着斑激酶(focal adhesion kinase,FAK)磷酸化对细胞外基质成份诱导的气道上皮细胞增殖和细胞周期演进的影响,探讨粘着斑激酶活化对气道上皮细胞损伤后修复影响的机制。方法:通过纤维连接蛋白(finbronectin,FN)诱导培养的气道上皮细胞,利用四唑盐(MTT)比色实验研究气道上皮细胞增殖情况,采用流式细胞术分析气道上皮细胞细胞周期各期分布,以Western blot和免疫共沉淀检测FAK表达水平及其酪氨酸磷酸化程度;以FAK反义寡核苷酸(ODNs)经脂质体转染细胞,观察其对FAK磷酸化、细胞增殖和细胞在细胞周期各期分布的影响。结果:FN诱导的气道上皮细胞MTT吸光度明显增强,G1期细胞数量明显减少,S期和G2期细胞数量明显增多,同时FAK表达水平及其酪氨酸磷酸化程度显著增高;经脂质体转染了反义FAK寡核苷酸的气道上皮细胞MTT吸光度值显著降低,G1期细胞数明显增多,S期和G2期细胞数显著减少,FAK表达水平及其酪氨酸磷酸化程度降低,且与G1期细胞数量的增多成显著负相关,与S期、G2期细胞数量和MTT吸光度的减少成明显正相关。结论:FAK是细胞外基质诱导气道上皮细胞增殖的重要信号分子,其活化促进气道上皮细胞的增殖和细胞周期的演进,在气道上皮细胞损伤后修复过程中起重要作用。

Transforming growth factor-β1 induces intestinal myofibroblast differentiation and modulates their migration

AIM:To investigate the effects of transforming growth factorβ1(TGF-β1)on the differentiation of colonic lamina propria fibroblasts(CLPF)into myofibroblasts in vitro. METHODS:Primary CLPF cultures were incubated with TGF-β1 and analyzed for production ofα-smooth muscle actin(α-SMA),fibronectin(FN)and FN isoforms.Migration assays were performed in a modified 48-well Boyden chamber.Levels of total and phosphorylated focal adhesion kinase(FAK)in CLPF were analyzed after induction of migration.RESULTS:Incubation of CLPF with TGF-β1 for 2 d did not changeα-SMA levels,while TGF-β1 treatment for 6 d significantly increasedα-SMA production. Short term incubation(6 h)with TGF-β1 enhanced CLPF migration,while long term treatment(6 d)of CLPF with TGF-β1 reduced migration to 15%-37% compared to untreated cells.FN and FN isoform mRNA expression were increased after short term incubation with TGF-β1(2 d)in contrast to long term incubation with TGF-β1 for 6 d.After induction of migration, TGF-β1-preincubated CLPF showed higher amounts of FN and its isoforms and lower levels of total and phosphorylated FAK than untreated cells. CONCLUSION:Long term incubation of CLPF with TGF-β1 induced differentiation into myofibroblasts with enhancedα-SMA,reduced migratory potential and FAK phosphorylation,and increased FN production.In contrast,short term contact(6 h)of fibroblasts with TGF-β1 induced a dose-dependent increase of cell migration and FAK phosphorylation without induction ofα-SMA production.

Syntenin异常表达促进胶质瘤侵袭和迁移的研究

目的探讨多配体蛋白聚糖结合蛋白（Syntenin）促进脑胶质瘤迁移和侵袭过程的分子机制。方法应用RT-PCR技术和免疫印迹方法研究84例不同病理级别人脑胶质瘤组织中Syntenin与磷酸化FAKTyr397基因和蛋白的表达情况，比较二者与胶质瘤分级的关系以及表达的相关性。结果RT-PCR检测结果显示，Syntenin mRNA和FAK mRNA表达水平在各级胶质瘤组织之间均存在明显差异（P〈0．05），二者表达水平的上调均与肿瘤级别的增加呈正相关（rSyntenin=0．91，P〈0．05；r FAK=0．97，P〈0．05）；免疫印迹结果发现，Syntenin和磷酸化FAKTyr397的表达在各级胶质瘤组织中存在差异（P〈0．05）；其表达水平均随胶质瘤病理级别的增加而上调（rSyntenin=0．91，P〈0．05；rFAK=0．90，P〈0．05）；Syntenin表达水平的提高与FAK Tyr397的磷酸化水平呈正相关（r=0．90，P〈0．05）。结论脑胶质瘤细胞中Syntenin可能通过与FAK相互作用经相应的信号转导途径增加脑胶质瘤细胞迁移和侵袭的能力。

粘着斑激酶相关非激酶质粒转染抑制肝星状细胞周期进程及机制研究

粘着斑激酶（focal adhesion kinase，FAK）磷酸化后，对多种类型细胞的生物学行为具有重要影响，如促进增殖，正性调控细胞周期，增强粘附、迁移，控制凋亡等。粘着斑激酶相关非激酶（FAK—related non-kinase，FRNK）是FAK的内源性抑制剂。本研究应用体外细胞培养技术，以纤维连接蛋白（fibronectin，FN）刺激肝星状细胞（hepatic stellate cell，HSC）增殖，在脂质体介导下瞬时转染FRNK质粒，探讨选择性阻断FAK磷酸化对HSC增殖周期及细胞周期相关蛋白的影响。