水通道蛋白-4表达变化与急性高眼压视网膜损伤的相关性研究

目的 观察不同高眼压作用下,水通道蛋白-4(AQP4)及其mRNA在大鼠视网膜内的表达变化.以探讨AQP4与眼压异常性疾病的关系.方法 采用前房加压灌注法.分别制作75cm、125cm和150cm水柱不同压力急性高眼压大鼠模型;通过HE和尼氏染色了解视网膜病理改变和神经节细胞数目变化;应用免疫组织化学、免疫荧光双标、原位杂交以及RT-PCR等技术检测不同高眼压作用下,AQP4及其mRNA在视网膜内的表达变化.结果 与对照组相比,各实验组大鼠视网膜晕不同程度水肿样改变,其内层厚度增加,神经节细胞数目明显减少;AQP4及其mRNA在视网膜内的表达明显增强,其表达上调水平与眼压升高程度呈正相关,并与视网膜内层厚度增加以及节细胞数目减少相关(P<0.01).结论 急性高眼压作用下,大鼠视网膜内AQP4及其mRNA的表达明显增强,呈压力依赖性,其异常高表达可能与急性高眼压的病理损伤过程以及眼内水、电解质代谢失衡有关.     

水通道蛋白-4 mRNA沉默可抑制离体缺氧星形胶质细胞水通道蛋白-4的表达

目的:研究水通道蛋白-4(AQP4) mRNA沉默对体外缺氧星形胶质细胞AQP4表达的影响.方法: 用氯化钴诱导体外星形胶质细胞缺氧,建立AQP4 mRNA沉默缺氧星形胶质细胞模型.随机分为正常组、对照组、缺氧组和干扰组,观察星形胶质细胞形态,免疫细胞化学、荧光定量PCR、免疫印迹法检测AQP4 mRNA 及蛋白表达....     

水通道蛋白在胶质细胞的表达及其意义

20世纪80年代,美国学者Peter Agre发现质膜上存在一类介导水快速跨膜转运的膜蛋白,这类膜蛋白被称作水通道蛋白.已有大量研究发现胶质细胞表达的水通道蛋白对神经系统疾病的发生有重要作用.本文综述水通道蛋白在胶质细胞的表达定位及其意义,为中枢和周围神经系统疾病的诊断和治疗提供新的靶点.     

脊髓损伤后水通道蛋白-4的时程变化

探讨脊髓损伤后水通道蛋白-4及其mRNA的变化规律,应用改良Allen脊髓损伤的模型,于术后1、3、7和14 d取脊髓组织,采用免疫组织化学和原位杂交技术检测AQP-4的表达。结果表明,AQP-4及其mRNA表达丰富的部位主要集中在损伤脊髓的后索、前索和后角,以小胶质细胞和少突胶质细胞为主。AQP-4及其mRNA表达在脊髓损伤后1 d开始增加,在脊髓损伤后3 d达到高峰。随后下降,对应的病理改变为细胞内水肿。本研究结果提示:胶质细胞AQP-4表达增强与早期损伤性脊髓水肿密切相关,它可能是形成早期细胞内水肿的重要因素之一。     

渗透压改变与星形胶质细胞水通道蛋白9表达的关系

目的:探讨渗透压对星形胶质细胞水通道蛋白9(AQP9)表达的影响.方法:通过H-E显色观察渗透压改变(对照组、低渗组和高渗组)对细胞形态的影响,台盼蓝染色评价细胞活力的变化,免疫细胞化学、原位杂交研究星形胶质细胞AQP9及其mRNA的表达变化.结果:对照组细胞形态、活力、AQP9及其mRNA的表达在各时间点均无明显变化.低渗培养导致细胞水肿,细胞活性下降,AQP9及其mRNA的表达水平明显高于对照组,并随低渗作用的增强和时间的延长而上调.高渗作用可导致细胞皱缩,细胞活性下降,AQP9及其mRNA表达在12 h内持续增加后下降,至24 h后仍高于对照组.结论:低渗液作用下AQP9及其mRNA的表达上调,作为一种病理性适应反应参与了胶质细胞水肿的形成.高渗作用早期(约12 h内),AQP9的表达上调对高渗型细胞脱水起到重要的代偿作用.     

水通道蛋白-4在大鼠甲状腺中的表达

目的:观察水通道蛋白-4(AQP4)在甲状腺滤泡细胞的表达和分布特点,为研究甲状腺内分泌及调节机制提供形态学基础。方法:利用免疫组织化学、免疫荧光组织化学和原位杂交组织化学技术,检测大鼠AQP4及其mRNA在甲状腺滤泡上皮细胞的表达。结果:免疫组织化学和免疫荧光组织化学显示,AQP4在甲状腺滤泡上皮细胞膜上有表达,而在上皮细胞基底面和管腔面表达更为明显;原位杂交组织化学显示AQP4 mRNA在上皮细胞中表达明显。结论:AQP4在甲状腺的表达和分布特点,提示其参与了甲状腺素的合成和分泌过程中渗透压的精细调节作用。     

水通道蛋白-4与脑水肿关系研究进展

脑水肿是指脑组织内的异常水分潴留，使脑体积增大，是多种疾病伴发的一种病理状态。脑水肿的非手术治疗的方法有渗透性利尿、高张盐水，亚低温治疗等，尚没有针对脑水肿分子机制的有效治疗。水通道蛋白（AQP）是膜水通道蛋白家族，为调节跨细胞水平衡的选择性孔道，迄今在哺乳动物中已发现13种水通道蛋白（AQPO-AQPl2）^[1]。     

水通道蛋白-4在大鼠睾丸和附睾中的表达

目的 观察水通道蛋白-4（AQP4）在雄性大鼠睾丸和附睾的表达及分布特点,为探讨水通道蛋白在睾丸和附睾中的作用提供形态学基础。方法 采用免疫组织化学的方法,检测AQP4在睾丸和附睾的表达分布。结果 AQP4在睾丸中表达于各级生精细胞、支持细胞以及间质细胞中;在附睾管内表达于柱状上皮细胞,且腔面表达更明显。结论 AQP4可能参与了精子的生成及成熟过程,在激素的分泌调节中发挥作用。     

miR-29a调控水通道蛋白4抑制过氧化氢诱导的星形胶质细胞凋亡

背景：一些研究已经证实了miR-29a、水通道蛋白4在星形胶质细胞损伤过程中的作用,但其是否存在相互作用以及分子机制尚未见报道。目的：研究miR-29a调控水通道蛋白4表达对过氧化氢诱导星形胶质细胞损伤的影响。方法：(1)以小鼠原代培养的星形胶质细胞为研究对象,用不同浓度的过氧化氢诱导小鼠星形胶质细胞损伤反应,细胞分为对照组、过氧化氢组、过氧化氢+空载体组、过氧化氢+miR-29a过表达组。采用MTT法检测小鼠星形胶质细胞存活率;Western blot法检测小鼠星形胶质细胞凋亡相关蛋白(Bcl-2、Bax、cleaved-Caspase-3)、水通道蛋白4和胶质纤维酸性蛋白的蛋白表达水平;实时定量PCR检测小鼠星形胶质细胞中miR-29a的表达水平;流式细胞仪检测小鼠星形胶质细胞凋亡水平。(2)将12只雌性BALB/c小鼠随机分为空载体组、过表达miR-29a组,每组6只。制备小鼠T₁₀脊髓撞击损伤动物模型,建模后分别注射以下重组慢病毒(空载体、miR-29a过表达载体)。术后第7天,采用免疫组织荧光染色检测小鼠脊髓损伤部位水通道蛋白4和胶质纤维酸性蛋白表达水平...     

水通道蛋白-4在实验性脊髓损伤大鼠的表达

为了观察大鼠脊髓损伤后水通道蛋白4(AQP 4)的表达和对后肢功能的影响,本实验建立Allen脊髓损伤动物模型,于术后1、3、7、14和21d分别对大鼠进行了BBB评分检查后肢功能,处死动物后应用免疫组织化学技术检测脊髓组织内AQP 4的表达,用图像分析仪对脊髓损伤后神经组织的AQP 4的变化进行了定量分析。结果表明:脊髓损伤后第1d,在脊髓损伤组受损伤脊髓灰质和白质中均可见到AQP 4的表达明显增加;第3d时均达到高峰。在第7、14、和21d,AQP 4的表达与对照组均有显著性差异(P<0. 01)。本研究结果提示:脊髓损伤后大鼠脊髓组织中AQP 4的表达显著增加。     

Lysosomal degradation of retinal glial AQP4 following its internalization induced by acute ocular hypertension

The membrane-bound water channel aquaporin-4 plays a significant role in the regulation of water movement within the retina. In retinal ischemia-reperfusion injury, changes in the expression and localization of aquaporin-4 have been reported. Previous studies also suggest that the internalization of several membrane-bound proteins, including aquaporin-4, may occur with or without lysosomal degradation. In this study, the internalization of aquaporin-4 was detected in the ischemic rat retina via double immunofluorescence labeling. Specifically, both aquaporin-4 and the mannose-6-phosphate receptor co-localized post-ischemic injury (10, 30 and 60 min). The same results were found during a 12-h reperfusion window (2, 4 and 8 h, respectively) following 60 min of ischemia. Moreover, the co-expression of aquaporin-4 and lysosomal-associated membrane protein-1 was observed at 1-12 h of reperfusion, with co-expression increasing followed by a gradual decrease. These combined findings suggest that AQP4 is internalized in the ischemic-reperfused retina, and the lysosome is involved in degrading the internalized aquaporin-4 during the reperfusion phase. Both the internalization of aquaporin-4 and its lysosomal degradation may serve as valuable therapeutic targets for managing ischemic-reperfused retinal injury.     

Close association of aquaporin-2 internalization with caveolin-1

Aquaporin 2 (AQP2) is a membrane water channel protein that traffics between the intracellular membrane compartment and the plasma membrane in a vasopressin-dependent manner in the renal collecting duct cell to control the amount of water reabsorption. We examined the relation between AQP2 internalization from the plasma membrane and caveolin-1, which is a major protein in membrane microdomain caveolae, in Mardin-Darby canine kidney cells expressing human AQP2 (MDCK-hAQP2 cells). Double-immunofluorescence microscopy showed that AQP2 is colocalized with caveolin-1 in the apical plasma membrane by stimulating the intracellular signaling cascade of vasopressin with forskolin. After washing forskolin, both AQP2 and caveolin-1 were internalized to early endosomes and then separately went back to their individual compartments, which are subapical compartments and the apical membrane, respectively.Double-immunogold electron microscopy in ultrathin cryosections confirmed the colocalization of AQP2 with caveolin-1 at caveolar structures on the apical plasma membrane of forskolin-treated cells and the colocalization within the same intracellular vesicles after washing forskolin. A co-immunoprecipitation experiment showed the close interaction between AQP2 and caveolin-1 in forskolin-treated cells and in cells after washing forskolin. These results suggest that a caveolin-1-dependent and possibly caveolar-dependent pathway is a candidate for AQP2 internalization in MDCK cells.     

Internalization of Aquaporin‐4 After Collagenase‐Induced Intracerebral Hemorrhage

Brain edema formation following intracerebral hemorrhage (ICH) appears to be related with aquaporin‐4 (AQP4), which is critically involved in brain volume homeostasis and water balance. Despite its importance, the regulation of AQP4 expression involved in transmembrane water movements still remains rudimentary. Many studies suggest that the internalization of several membrane‐bound proteins, including AQP4, may occur with or without lysosomal degradation. Previously, we investigated the internalization of AQP4 in retinal ischemic‐reperfusion model. Here, we test the hypothesis that AQP4 is internalized post‐ICH and then degraded in the lysosome. The results demonstrated that both AQP4 and the mannose‐6‐phosphate receptor (MPR) co‐localized in perihematomal region at 6 hr post‐ICH. In addition, AQP4 and lysosomal‐associated membrane protein 1 (LAMP1) also co‐localized in perihematomal region, with co‐expression increasing followed by a gradual decrease at different time windows post‐ICH (6, 12, 24, 48, and 72 hr). After ICH, the Evans blue leakage happened very early at 1 hr and the brain swelling occurred at 3 hr. Moreover, we also found the AQP4 mRNA and AQP4 protein were increased post‐ICH. These results suggest that AQP4 is internalized and the lysosome is involved in degrading the internalized AQP4 post‐ICH. Both the AQP4 internalization and lysosomal degradation may provide biophysical insights regarding the potential of new treatments for brain edema. Anat Rec, 298:554–561, 2015. © 2014 Wiley Periodicals, Inc.     

外源性脑源性神经营养因子对急性高眼压后大鼠视网膜谷氨酸转运体1表达的影响

目的:检测外源性脑源性神经营养因子(BDNF)对急性高眼压后大鼠视网膜谷氨酸转运体1(GLT-1)表达的影响。方法:72只SD大鼠随机分成急性高眼压组、溶媒预处理急性高眼压组和BDNF预处理急性高眼压组,每组动物左眼制作急性高眼压模型,右眼为正常对照,每组动物分别存活1、3、7或14d。用免疫组织化学方法检测外源性BDNF对视网膜GLT-1表达的影响。结果:溶媒预处理急性高眼压组中GLT-1的表达与急性高眼压组相同。与正常视网膜比,急性高眼压组GLT-1的表达在再灌1d时上调,3d时达到高峰,7、14d时表达下调,但仍高于正常对照组。在BDNF预处理急性高眼压组,再灌1d时GLT-1表达明显高于急性高眼压组,3、7、14d时GLT-1表达与急性高眼压组无明显差别。结论:外源性BDNF对急性高眼压后大鼠视网膜的保护作用可能与再灌早期提前上调GLT-1的表达有关。     

水通道蛋白-1在急性肾损伤中的作用

急性肾损伤的发病率与病死率较高,严重威胁着患者的健康与生命。水通道蛋白-1是肾近曲小管上皮细胞中大量表达的通道蛋白,其含量在急性肾损伤过程中变化显著,并且在肾保护药物干预中也有明显改变。机制研究提示水通道蛋白-1可能通过参与上皮细胞迁移和调节上皮间质转化过程实现可能的肾保护作用。将水通道蛋白-1作为靶分子,可能会对治疗急性肾损伤的药物研发提供新的思路。     

Effects of dexamethasone on aquaporin-4 expression in brain tissue of rat with bacterial meningitis

Aquaporin-4 (AQP4) is the most popular water channel protein expressed in brain tissue and plays a very important role in regulating the water balance in and outside of brain parenchyma. To investigate the expression of aquaporin-4 in the rat brain tissue after dexamethasone therapy of meningitis induced by Streptococcus pneumonia, total 40 of 3-week old Sprague-Dawley rats were divided into infection group (n=30) and normal control group (n=10). The meningitis groups were infected with 1×10⁷ cfu/ml of Streptococcus pneumoniae and then randomized into no treatment (untreated group, n=10), treatment with ceftriaxone (CTRX group, n=10) and treatment with dexamethasone combined ceftriaxone (CTRX + DEXA group, n=10). The normal control group was established by using saline. The rats were euthanized when they reached terminal illness or five days after infection, followed by detection of AQP4 through using immunohistochemistry and Western blot methods. Data has showed that expression of AQP4 in model group remained higher than the control and treatment group (P<0.05). AQP4 expression in CTRX + DEXA group was lower than that in CTRX group (P<0.05). There was no statistical difference between CTRX + DEXA group and the control group (P>0.05). These data suggested that Dexamethasone could down-regulate the expression of AQP4 in the brain tissue of rats with meningitis and provides evidence for the mechanism of protective effect of Dexamethasone on central neurosystem.     

vMIP-II对细胞表面趋化因子受体CXCR4内化及调变的研究

研究利用激光共聚焦显微镜和流式细胞仪分别定性、定量检测CXCR4的内化,观察vMIP-II对细胞表面趋化因子受体CXCR4内化的影响,用荧光分光光度计连续动态检测vMIP-II对细胞内钙离子浓度的影响,以阐明vMIP-II抗HIV/AIDS的作用机制。结果表明100 ng/ml vMIP-II在给药后的最初30 min能使细胞表面受体CXCR4内化达到最大值,内化率约为75%,且内化到细胞内的CXCR4并不能再循环到细胞表面。vMIP-II能诱导瞬间的高钙离子内流及细胞内钙离子库中钙离子的释放,证明了vMIP-II能引起细胞表面受体CXCR4的内化,内化的受体不再循环到细胞表面。     

Hypoxia-induced expression of vascular endothelial growth factor by retinal glial cells promotes in vitro angiogenesis

To determine whether retinal glial cells (RGCs) participate in the paracrine regulation of retinal neovascularization, we investigated whether cultured RGCs synthesize and release vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) under normoxic or hypoxic conditions. Northern blot analysis demonstrated that cultured RGCs transcribed both VEGF mRNA with two molecular bands approximately 3.9 and 4.3 kilobases (kb), and bFGF mRNA with approximately 3.7 and 6.0 kb. The expression of VEGF mRNA was greatly enhanced by hypoxic cultivation (2% oxygen) when compared with normoxic cultivation (20% oxygen), while the expression of bFGF mRNA by RGCs was not significantly affected by hypoxia. The effects of RGCs-conditioned media (CM) on tritiated-thymidine incorporation and in vitro angiogenesis by retinal capillary endothelial cells (RECs) in producing the formation of capillary-like tubes in type I collagen gels, were evident in the observation that RGCs-CM harvested after hypoxic cultivation significantly enhanced tritiated-thymidine incorporation (1.9 times, P<0.01) and in vitro angiogenesis (2.4 times, P<0.01) compared with the normoxic RGCs-CM. These enhancing effects of RGCs-CM at hypoxia were suppressed by anti-VEGF neutralizing antibody. Furthermore, RECs were shown to express mRNA encoding the VEGF receptor flt-1 by northern blot analysis. These results suggest that VEGF expressed by RGCs under hypoxic conditions plays an integral role in the initiation and progression of retinal neovascularization in a paracrine manner.     

Expression of N-methyl-d-aspartate receptor 1 in rats with chronic ocular hypertension

High levels of glutamate can be toxic to retinal ganglion cells (RGCs). This study investigated the relationship between the N-methyl-d-aspartate receptor 1 (NR) and RGC death in a rat model of chronic ocular hypertension (COHT). COHT was induced in one eye of each rat by episcleral vein cauterization. Retinal protein expression was evaluated at 1, 3, 5 and 9 weeks after cauterization. Quantitative real-time polymerase chain reaction and Western blot analysis showed that NR1 expression was significantly increased in cauterized retinae. NR1 immunoreactivity was observed in the inner nuclear layer (INL) and ganglion cell layer (GCL) in the retina of rats with COHT. RGC density was evaluated after retrograde labeling with fluoro-gold (FG) and 4-di-10-ASP (DiA). A significant decrease in RGC density was observed in ocular hypertensive eyes, and NR1 expression in the GCL suggested an important role of NR1 in the death of RGCs. Memantine (10 mg/kg), an N-methyl-d-aspartate receptor antagonist, was administered orally once daily for up to 5 weeks, while rats in the control group received vehicle phosphate-buffered saline only. Treatment with memantine resulted in a significant reduction in RGC loss and NR1 expression in the eyes of rats COHT. These findings suggest that excessive expression of NR1 is involved in RGC death in glaucoma.