陷窝蛋白在脑缺血后血脑屏障破坏中的作用

陷窝蛋白是陷窝的主要组成蛋白，也是实现其生理功能的重要蛋白。陷窝蛋白表达于平滑肌细胞、内皮细胞和脂肪细胞。陷窝既参与了细胞的脂肪摄取、胞吞和胞饮等基本生理过程，也对细胞的信号转导以及大分子物质的转运和通透起着非常重要的作用。随着对陷窝蛋白的分子构成和生物化学功能研究的深入，越来越多的研究表明陷窝及其主要成分陷窝蛋白在脑血管病的病理生理学过程起着重要作用。文章就陷窝蛋白在脑缺血后血脑屏障破坏中的作用进行了综述。     

陷窝蛋白-1与脑缺血后炎性反应

陷窝蛋白-1作为陷窝的标志蛋白,通过其脚手架结构域寡聚许多细胞信号转导分子,参与许多病理生理过程,也通过不同的途径调控脑缺血后炎症反应。文章对近年来陷窝蛋白-1与缺血性卒中后炎性反应相关研究进展进行了回顾,重点讨论其炎症调控机制。     

高脂饮食性非酒精性脂肪性肝病小鼠肝脏陷窝蛋白-1的变化

目的 探索陷窝蛋白-1在高脂饮食性非酒精性脂肪性肝病(NAFLD)发病中的作用.方法 给予12只10周龄雄性C57BL/6小鼠高脂高胆固醇饮食14周,建立NAFLD的动物模型作为实验组.同时,普通饮食饲养同种系小鼠6只作为对照组.第14周末处死全部小鼠,比较两组体质量、肝质量和血脂变化.分别用实时荧光定量PCR(qPCR)和Western印迹法检测陷窝蛋白-1在NAFLD小鼠肝组织中的基因和蛋白表达水平变化.苏木精-伊红染色后光学显微镜下观察小鼠肝脏的脂肪变性情况,免疫组织化学染色后观察陷窝蛋白-1在肝组织中分布的变化.采用t检验比较两组肝组织中陷窝蛋白-1 mRNA及蛋白水平的差异,Mann-whitney U检验分析不同程度脂肪肝小鼠的肝脏陷窝蛋白-1表达的免疫组织化学积分差异.结果 实验组小鼠在高脂高胆固醇饮食14周后全部发生NAFLD,其中重度9只,中度3只.与对照组比较,实验组小鼠的血清TC[(1.940±0.300) mmol/L比(3.771±0.800) mmol/L,t=-3.760]、高密度脂蛋白胆固醇[(1.120±0.066)mmol/L比(2.224±0.420) mmol/L,t=-5.474]、低密度脂蛋白胆固醇[(0.510±0.191) mmol/L比(1.241±0.660) mmol/L,t=-3.332]均显著升高(P均＜0.01),但TG差异无统计学意义(P＞0.05).实验组小鼠肝脏陷窝蛋白[1的mRNA(1.536±0.226比0.980±0.272,t=3.371,P＜0.05)和蛋白水平(0.643±0.240比0.100±0.130,t=-4.847,P＜0.01)均显著高于对照组.免疫组织化学结果显示,表达增加的陷窝蛋白-1主要分布于肝细胞膜、脂滴膜和细胞质中.结论 高脂高胆固醇饮食诱导的NAFLD小鼠肝脏陷窝蛋白1水平上调,可能参与了NAFLD的发病机制.     

单核细胞Toll样受体和髓样分化蛋白表达水平与T2DM神经病变患者炎症反应的关系

目的探讨单核细胞Toll样受体(TLR)4和髓样分化蛋白(MyD88)表达与2型糖尿病(T2DM)神经病变患者炎症反应的关系及作用机制。方法收集T2DM患者210例,其中无神经病变(TDM组)120例,伴周围神经病变(DPN组)90例;另选取同年龄段健康志愿者100名为对照组。单次抽取受试者空腹肘静脉血10 ml,梯度离心分离血清和血浆,分离单核细胞;RT-PCR法检测单核细胞中TLR4、陷窝蛋白-1 mRNA表达;Western印迹法检测TLR4、陷窝蛋白-1及其下游信号蛋白(MyD88、IκB、p-IκB)表达;酶联免疫吸附试验(ELISA)检测血浆中促炎因子〔白细胞介素(IL-6)、肿瘤坏死因子(TNF-α)〕水平。结果TDM组、DPN组血浆IL-6、TNF-α浓度均明显高于对照组,TDM组患者血浆IL-6、TNF-α浓度明显高于DPN组(P<0.05)。TDM组、DPN组患者TLR4、陷窝蛋白-1 mRNA相对表达量均明显高于对照组,TDM组患者TLR4、陷窝蛋白-1 mRNA相对表达量明显高于DPN组(P<0.05)。Spearman分析显示,TLR4 mRNA表达与血浆IL-6、TNF-α均呈显著正相关;TLR4 mRNA表达与陷窝蛋白-1 mRNA呈显著负相关。TDM组、DPN组患者陷窝蛋白-1、IκB蛋白相对表达量明显低于对照组,TLR4、MyD88、p-IκB蛋白相对表达量明显高于对照组(P<0.05);与TDM组相比,陷窝蛋白-1、IκB蛋白相对表达量明显减少,TLR4、MyD88、p-IκB蛋白相对表达量明显增加(P<0.05)。结论T2DM神经病变患者炎症状态与单核细胞TLR4、MyD88信号通路介导的炎症级联反应有关;陷窝蛋白-1表达下调与TLR4、MyD88信号通路异常活化有关。     

钙调素与脑血管病

钙调素是一种多功能钙受体蛋白,参与多种生物代谢过程。近年来的研究表明,钙调素与脑血管病密切相关。文章就钙调素的理化特性、分布和功能,钙调素在脑血管病中的变化和作用机制以及钙调素拮抗剂应用的研究进展进行了综述。     

钙调素与脑血管病

钙调素是一种多功能钙受体蛋白，参与多种生物代谢过程，近年来的研究表明，钙调素与脑血管病密切相关， 文章就钙调素的理化特性，分布和功能，钙调素在脑血管病中的变化和作用凤及钙调素拮抗剂的研究进展进行了综述。     

Light诱导类风湿关节炎滑膜细胞向破骨细胞转化

目的 观察Light在类风湿关节炎(RA)滑膜细胞向破骨细胞转化过程中的作用.方法 取8例RA患者滑膜组织,胶原酶消化获取滑膜细胞,每例滑膜细胞分成5份培养,第1组加入巨噬细胞集落刺激因子(MCSF)作阴性对照,第2组加入MCSF和LIGHT,第3组加入MCSF和核因子(NF)-κB受体激动剂配体(RANKL),第4组加入MCSF、LIGHT和RANKL,第5组加入LIGHT.体外培养2周后,行抗酒石酸酸性磷酸酶(TRAP)染色,F肌动蛋白(F-actin)染色以及象牙片上骨吸收陷窝观察破骨细胞的形成和活性.结果 第1组和第5组TRAP(-),F-actin(-),象牙片上无骨吸收陷窝形成;第2组TRAP(+),F-actin(+),骨陷窝形成(+),多核破骨细胞呈圆形和椭圆形,体积较小,骨陷窝分散,体积较小;第3组TRAP(++).F-actin(++),骨陷窝形成(++),多核破骨细胞体积大,骨陷窝较多,体积大,形态不规则;第4组TRAP(+++),F-actin(+++),骨陷窝形成(++++),多核破骨细胞更多,骨陷窝大且有融合趋势.结论 Light能诱导RA滑膜细胞向破骨细胞转化,并能促进RANKL诱导滑膜细胞向破骨细胞转化的能力.     

Apelin-APJ系统与血管发生

血管发生是治疗缺血性脑血管病的有效策略之一,且多种促血管生成因子和血管生成抑制因子参与该过程的调节.Apelin是一种新发现的多肽,为G蛋白耦联受体APJ(血管紧张素1型受体相关蛋白)的内源性配体.Apelin和APJ在大鼠和人体的心脏、大脑等多种组织器官广泛表达.Apelin-APJ系统具有促血管生成作用,在缺血性病的治疗方面具有重要意义.文章对apelin-APJ系统在血管发生方面的作用机制及研究进展做了综述.     

蛋白酪氨酸磷酸酶1B与细胞信号转导

蛋白酪氨酸磷酸酶-1B(PTP-1B)通过对细胞内不同蛋白底物脱磷酸化参与不同的生理反应,在胰岛素、瘦素等多条细胞信号通路中发挥作用.因其参与多种生理、病理过程,近年来PTP-1B抑制剂的提取和研制成为相关疾病防治的新方向.     

血清S-100蛋白检测在急性脑血管疾病中的应用

S-100蛋白是神经胶质细胞的特异性标记物。血清S-100蛋白的水平可反映中枢神经系统损伤的范围和严重程度。S-100蛋白可能还参与了急性脑血管病的病理生理过程。测定血清S-100蛋白的浓度对判断急性脑血管病的严重程度、估计其预后有重要意义。     

Epithelial expression of caveolin-2, but not caveolin-1, is enhanced in the inflamed mucosa of patients with ulcerative colitis

Caveolae are vesicular invaginations of the plasma membrane that act as a scaffold of the assembly of many classes of signaling molecules. Caveolins are the principal structural component of caveolae membranes, and three distinct forms of caveolins have been identified: caveolin-1, caveolin-2, and caveolin-3. In this study, we evaluated the changes in the caveolin-1 and caveolin-2 expression in the inflamed mucosa of patients with IBD. Tissue samples were obtained endoscopically from patients with ulcerative colitis (UC) (n = 18), Crohn's disease (n = 10) and ischemic colitis (n = 8). Normal colorectal tissues were also obtained (n = 15). The caveolin expression was evaluated by standard immunohistochemical procedure. In normal colonic mucosa, caveolin-1 expression was detected in the smooth-muscle cells of the muscularis mucosae and the endothelial cells, but caveolin-2 expression was not detected. In the inflamed mucosa of patients with active UC, caveolin-2 expression was clearly detectable as small scattered foci on the luminal surfaces of epithelial cells, but caveolin-1 expression was similar to that in normal mucosa. Caveolin-2 expression increased in accordance with the disease activity of UC. This enhanced caveolin-2 expression was not detected in active Crohn's disease or ischemic colitis. In conclusion, we demonstrated that the epithelial expression of caveolin-2 is markedly enhanced in the inflamed mucosa of patients with UC. It is likely that the enhanced caveolin-2 expression in patients with UC was associated with the altered signal transductions in the intestinal epithelial cells. Furthermore, our results suggest that there are differences in the phenotypic features of epithelial cells between UC and Crohn's disease.     

Oestrogen-mediated tyrosine phosphorylation of caveolin-1 and its effect on the oestrogen receptor localisation: an in vivo study

Recently, it has been shown that 17beta estradiol (E2) induces a rapid and transient activation of the Src ERK phosphorylation cascade: a clear indication that the alpha oestrogen receptor (ERalpha) is able to associate with the plasma membrane. Increasing evidence suggests that caveolae, which are caveolin-1 containing, highly hydrophobic membrane domains, play an important role in E2 induced signal transduction. Caveolae can accumulate signalling molecules preferentially; thus, they may have a regulatory role in signalling processes. Results from previous experiments have shown that E2 treatment decreased the number of surface connected caveolae significantly in uterine smooth muscle cells and also downregulated the expression of caveolin-1. In addition to providing further evidence that ERalpha interacts with caveolin/caveolae in uterine smooth muscle cells, this study also shows that the interaction between caveolin-1 and ERalpha is actually facilitated by E2. One of the signal transduction components found to accumulate in caveolae is Src kinase in an amount that increases simultaneously with increases in the amount of ERalpha. Upon E2 treatment, Src kinase is tyrosine phosphorylated, which, in turn, stimulates Src kinase to phosphorylate caveolin-1. Phosphorylation of caveolin-1 can drive caveolae to pinch off from the plasma membrane, thereby decreasing the amount of plasma membrane-associated caveolin-1. This loss of caveolin/caveolae activates the signal cascade that triggers cell proliferation.     

Caveolin,caveolae, and endothelial cell function

Caveolae are 50- to 100-nm cell-surface plasma membrane invaginations observed in terminally differentiated cells. They are particularly abundant in endothelial cells, where they are believed to play a major role in the regulation of endothelial vesicular trafficking and signal transduction. The use of caveolin-1-deficient mice has provided many new insights into the roles of caveolae and caveolin-1 in the regulation of endothelial cell function. These novel findings suggest an important role for caveolin-1 in the pathogenesis of cancer, atherosclerosis, and vascular disease.     

Expression of caveolin-1 in gastrointestinal and extraintestinal cancers

Caveolae are uniform vesicular invaginations of the cell membrane. Caveolin-1 is responsible for the formation of caveolae and plays a key role in membrane traffic and signal transduction. The contribution of caveolin-1 to carcinogenesis has been widely investigated; however, the expression pattern of caveolin-1 is controversial both in gastrointestinal and extraintestinal cancers. Most of the results based on cancer cell line experiments suggest that caveolin-1 might act as a tumor-suppressor gene. On the contrary, several studies on the expression of caveolin-1 in tumor tissues indicate a possible tumor-promoting effect of caveolin-1. In this article we summarize the divergent results of caveolin-1 expression in gastrointestinal and extraintestinal cancer regarding possible future therapeutic implications.     

Caveolin-1、Caveolae和动脉粥样硬化

Caveolae是细胞表面直径为50—100nm的胞膜穴样内陷,主要由胆固醇、糖基鞘磷脂、鞘磷脂和一些结构蛋白如Caveolin组成。Caveolin-1是Caveolae的主要组成成分,它与细胞骨架蛋白间接偶联来维持Caveolae的内陷形态。Caveolae和Caveolin-1在参与动脉粥样硬化的各种细胞如内皮细胞、巨噬细胞、平滑肌细胞表面都有表达,它们通过对各种细胞功能和多个信号转导途径的调节参与对动脉粥样硬化的形成和发展。     

The phosphorylation of caveolin-2 on serines 23 and 36 modulates caveolin-1-dependent caveolae formation

Caveolin-1 and -2 are the two major coat proteins found in plasma membrane caveolae of most of cell types. Here, by using adenoviral transduction of either caveolin-1 or caveolin-2 or both isoforms into cells lacking both caveolins, we demonstrate that caveolin-2 positively regulates caveolin-1-dependent caveolae formation. More importantly, we show that caveolin-2 is phosphorylated in vivo at two serine residues and that the phosphorylation of caveolin-2 is necessary for its actions as a positive regulator of caveolin-1 during organelle biogenesis in prostate cancer cells. Mutation of the primary phosphorylation sites on caveolin-2, serine 23 and 36, reduces the number of plasmalemma-attached caveolae and increases the accumulation of noncoated vesicles, but does not affect trafficking of caveolin-2, interaction with caveolin-1 or its biophysical properties. Thus, the phosphorylation of caveolin-2 is a novel mechanism to regulate the dynamics of caveolae assembly.     

Caveolin-1 interacts and cooperates with the transforming growth factor-beta type I receptor ALK1 in endothelial caveolae

AIMS: Activin receptor-like kinase (ALK)1 is a transforming growth factor (TGF)-beta type I membrane receptor restricted almost entirely to endothelial cells (ECs) and involved in vascular remodelling and angiogenesis. Previous reports have shown that the ubiquitous TGF-beta type I receptor ALK5 and the type II receptor are located in cholesterol-rich membrane microdomains named caveolae. The aim of this work was to assess the location of ALK1 in endothelial caveolae as well as to study the role of caveolin-1 on the TGF-beta/ALK1 signalling pathway. METHODS AND RESULTS: The subcellular distribution of ALK1 was analysed by confocal microscopy and co-fractionation experiments in human ECs. The association between human ALK1 and caveolin-1 was studied in caveolin-1-deficient human epithelial cells by co-immunoprecipitation. The functional role of caveolin-1 on the ALK1-mediated TGF-beta signalling was elucidated using ALK1-specific luciferase reporters in human ECs, caveolin-1(-/-)mouse embryonic fibroblasts, and rat myoblasts. Confocal microscopy analyses, as well as cholesterol depletion experiments in the presence of cholesterol-depleting agents such as nystatin or methyl-beta-cyclodextrin, demonstrated that ALK1 is located in endothelial caveolae. Also, co-immunoprecipitation assays showed that ALK1 associates with the main caveolae component caveolin-1. Mapping of the ALK1/caveolin-1 interaction revealed that the caveolin-1 scaffolding domain and the caveolin-1 binding motif in ALK1 are responsible for this association. Moreover, this hitherto not reported interaction had a functional consequence for the ALK1-dependent signalling. In contrast with the previously published ALK5/caveolin-1 interaction, caveolin-1 enhances the TGF-beta/ALK1 signalling pathway, promoting the activity of the ALK1-specific reporters. Conversely, specific suppression of caveolin-1 abrogated the ALK1 signalling pathway. CONCLUSION: ALK1 is located in endothelial caveolae where it functionally interacts with caveolin-1 through its scaffolding domain, suggesting a joint contribution of ALK1 and caveolin-1 as key mediators of the TGF-beta pathway in angiogenesis.     

颈动脉粥样硬化对缺血性脑血管病的影响

目的探讨颈动脉粥样硬化斑块对缺血性脑血管病的影响。方法选择我院神经内科住院的缺血性脑血管病患者68例，分为脑梗死组（CI组）43例和短暂性脑缺血组（TIA组）25例，另选同期门诊及病房非脑血管病患者32例（对照组），采用彩色多普勒血流显像技术对两组患者颈动脉粥样硬化斑块进行比较。结果68例缺血性脑血管病患者中，48例（70．6％）有动脉粥样硬化斑块，对照组5例（15．6％）有动脉粥样硬化斑块，两组患者粥样硬化斑块检出率间差异有显著性意义（P〈0．05）。68例缺血性脑血管病患者无症状侧颈动脉斑块检出率高于症状侧斑块检出率。CI、TIA两组患者无症状侧斑块检出率与症状侧斑块检出率间差异亦均有显著性意义（P〈0．05）。结论颈动脉粥样硬化是脑梗死的重要危险因素。对缺血性脑血管病患者，除常规检查颅脑影像学外，还应重视检查颈部血管。     

AMP-活化蛋白激酶与缺血性脑血管病

作为细胞内的能量感受器，AMP-活化蛋白激酶(AMP-activated protein kinase,AMPK)在维持细胞和机体能量平衡中发挥着重要作用。最初，AMPK在糖尿病、肥胖等代谢性疾病的病理生理学过程中的作用研究较多；近年来，AMPK在脑组织中的分布以及酸中毒、氧化应激损伤和细胞凋亡等病理生理学过程中的作用日益受到重视。同时发现，卒中后人为调节AMPK活性可改变神经细胞结局。因此，AMPK有望成为治疗缺血性脑血管病的新靶点。