水通道蛋白与肿瘤血管新生

肿瘤血管新生对于肿瘤的生长具有重要作用。水通道蛋白在肿瘤组织中常出现表达异常，并且可以促进肿瘤血管的新生及包括肿瘤血管内皮在内的多种细胞的迁移，与此同时，水通道蛋白与肿瘤血管的高通透性有关，这可能是肿瘤组织对水通道蛋白缺失具有较高敏感性的原因。鉴于水通道蛋白对于肿瘤特别是肿瘤血管新生的影响，其抑制剂可能成为新的肿瘤治疗的目标靶点。     

Orai1通道调控内质网应激反应参与糖尿病血管内皮损伤

目的:血管内皮损伤是糖尿病血管并发症的重要病理基础,早期研究发现Ca~(2+)稳态失衡参与内皮损伤,但是何种钙通道参与尚不十分明确。高糖可诱导内皮细胞上钙池操控性钙内流增加,同时内质网应激水平升高,因此本研究旨在研究Orai1通道对内质网应激反应的调控在糖尿病血管内皮损伤中的作用。方法:在动物及细胞水平利用Western blot和real-time PCR检测糖尿病状态下Orai1通道的表达变化及内质网应激反应水平;进一步利用Orai1 sh RNA腺病毒抑制该通道表达,在细胞水平观察其对高糖状态下内质网应激反应相关蛋白及内皮细胞磷酸化e NOS、NO生成的影响;在动物水平,利用血管张力测定仪检测Orai1通道对糖尿病小鼠血管内皮依赖性舒张反应的影响。结果:糖尿病状态下,Orai1表达及内质网应激水平均显著升高,抑制Orai1的表达可减少内质网应激标志物ATF4、CHOP、Bi P等的表达,同时逆转内皮细胞NO生成水平及内皮依赖性血管舒张功能障碍。结论:Orai1通道参与糖尿病内皮损伤,其机制与调控内质网应激反应有关。     

硫化氢在雌激素促血管内皮细胞增殖中的作用研究

目的研究硫化氢（H2S）在雌激素促进血管内皮细胞增殖中的作用。方法利用培养的脐静脉血管内皮细胞,以雌激素处理后,Western blot检测H2S产生关键酶CSE（胱硫醚-γ-裂解酶）的蛋白表达情况;亚甲基蓝法测定血管内皮细胞释放H2S含量;MTT法检测血管内皮细胞增殖情况。结果不同浓度（1nmo1／L～1μmol／L）的雌激素处理血管内皮细胞48h后．均可促进CSE蛋白表达和内皮H2S释放。不同浓度的雌激素均能明显促进血管内皮细胞增殖。以CSE特异性抑制剂PPG抑制H2S产生后,雌激素促进血管内皮增殖的能力受到显著抑制。结论雌激素可通过促进CSE蛋白表达促进血管内皮细胞释放H2S,进而促进血管内皮细胞增殖。     

脑水通道蛋白的分布、功能及调控机制

背景：在哺乳动物脑中主要表达的水通道蛋白是水通道蛋白1、水通道蛋白4和水通道蛋白9,其他的仅为零星表达。目前国内外尚未见到系统分析维持脑正常生理功能的水通道蛋白分布、功能及其调节机制的综述报道。 目的：综述近年国内外维持脑正常生理功能的水通道蛋白分布、功能及其调节机制的研究进展。 方法：应用计算机检索1980年1月至2013年7月PubMed数据库、中国期刊全文数据库有关脑正常生理功能维持中水通道蛋白分布、功能及其调节机制的文章,英文检索词“AQP1, AQP4,AQP9, function, brain, adjusting mechanism”;中文检索词“水通道蛋白,功能,脑,调节机制”。共检索到163篇相关文献,85篇文献符合纳入标准。 结果与结论：近年来,有大量学者对脑水通道蛋白的表达、功能及其调节机制进行了较深层次的研究,具体归纳为如下3个方面：①水通道蛋白1主要表达于脑室脉络丛参与脑脊液的形成;在其他类型的细胞中,气体小分子CO2,NO,NH3 及O2也可通过水通道蛋白1。②水通道蛋白4主要表达在胶质细胞足突、胶质界膜以及室管膜中,帮助水进出脑组织,并加速胶质细胞迁移及改变神经活动。③水通道蛋白9主要分布于星形胶质细胞及儿茶酚胺等神经元中,主要功能是参与脑内能量代谢。水通道蛋白被认为是对脑中水运输提供关键路径的主要水通道,有关水通道蛋白分布、功能及调控机制的研究对于攻克脑相关疾病起重要作用。水通道蛋白在维持脑正常生理及相关疾病中表达的调节机制尚未明晰,相关分子信号通路尚待更加深入、系统地研究。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

水通道蛋白在人喉组织的表达

目的:探讨水通道在喉组织中的分布及可能的功能。方法:通过RT-PCR、免疫印迹分别在RNA和蛋白水平明确喉组织中水通道的种类;采用免疫组织化学法对喉组织中的水通道蛋白进行定位分析。结果:水通道AQP1和AQP3在喉组织中表达:水通道蛋白AQP1在喉室黏膜假复层纤毛柱状上皮的纤毛、黏膜固有层的血管内皮及喉部神经纤维和神经节中表达;AQP3在喉黏膜鳞状上皮和固有层腺体上有表达。结论:喉组织中的水通道蛋白AQP1和AQP3在维持喉正常生理功能特别是发声中可能具有重要的作用。     

激素性股骨头坏死模型兔血管内皮细胞生长因子表达与普伐他汀的干预

背景：有研究表明他汀类药物可使体外培养的人脐静脉内皮细胞的血管内皮细胞生长因子呈高表达,血管内皮细胞生长因子可促进内皮细胞增殖,明显提高成骨细胞活性并加速骨形成。 目的：观察普伐他汀对激素性股骨头坏死兔模型血管内皮生长因子的蛋白表达的影响。 方法：将新西兰白兔随机分为对照组,模型组和普伐他汀组。模型组和普伐他汀组制备兔激素性股骨头缺血坏死模型。普伐他汀组建模成功后以普伐他汀(1.2 mg/kg)灌胃,1次/d,模型组和对照组以等体积的蒸馏水灌胃。于造模后8,12,16周截取各组股骨头行免疫组织化学检测血管内皮生长因子蛋白的表达情况。 结果与结论：对照组不同时间点股骨头血管内皮生长因子蛋白表达均为阳性。造模后8周,模型组血管内皮生长因子蛋白表达呈阴性表达,普伐他汀组呈弱阳性表达。造模后12周,模型组和普伐他汀组血管内皮生长因子蛋白表达呈阳性表达,16周呈弱阳性表达。结果证实,普伐他汀可有效促进早期激素性股骨头坏死兔模型坏死股骨头内源性血管内皮生长因子的蛋白表达。     

水通道蛋白1与肿瘤

<正>水通道蛋白家族是位于生物膜上具有快速水转运及离子转运功能的一族蛋白质。水通道蛋白1(Aquapor-in-1,AQP1)是第一个被发现的水通道蛋白,研究发现其不仅能介导水及离子转运,还对细胞内外气体交换、肿瘤血管的生成及细胞迁移产生重要影响     

血管内皮生长因子与促血管生成素1对大鼠血管内皮细胞的作用

背景：血管内皮生长因子、促血管生成素1是血管形成过程中始动并且使之持续的重要因子,研究其对血管内皮细胞的作用具有重要的意义。 目的：观察血管内皮生长因子与促血管生成素1对培养血管内皮细胞迁移与增殖能力的影响,并探讨其在血管生成方面的作用机制。 方法：在大鼠脐静脉内皮细胞内单独或联合加入血管内皮生长因子、促血管生成素1后,划痕实验和MTT检测对细胞迁移与增殖的影响,观察内皮细胞形态、活性、迁移能力。 结果与结论：划痕实验显示单独血管内皮生长因子作用时,与空白对照组细胞迁移无明显差异,单独促血管生成素1作用时,不仅不能增加细胞的迁移作用,反较空白对照组有所减弱,当血管内皮生长因子与促血管生成素1联合作用时,细胞迁移较空白对照组明显增强;MTT实验结果表明：单纯加入血管内皮生长因子或促血管生成素1,均不能起到有效促进内皮细胞增殖的作用;联合应用血管内皮生长因子及促血管生成素1可有效促进增殖。结果可见当血管内皮生长因子与促血管生成素1联合应用时,才能有效促内皮细胞迁移与增殖,发挥促血管生成作用。     

神经生长因子可促进骨折愈合过程中血管内皮生长因子的表达

背景：骨折愈合过程十分复杂,需要多种细胞因子的参与。目前研究较多的细胞因子有骨形态发生蛋白、成纤维细胞生长因子、转化生长因子β、血管内皮细胞生长因子和胰岛素样生长因子,但神经生长因子在骨折愈合过程中对血管内皮细胞生长因子的作用尚不明确。 目的：观察神经生长因子对兔骨折愈合中血管内皮生长因子表达的影响。 方法：实验建立标准兔桡骨骨折模型,分别用神经生长因子、神经生长因子单克隆抗体和生理盐水进行干预,即应用神经生长因子组、拮抗神经生长因子组和对照组。 结果与结论：损伤后24,48 h和损伤后1,3,6,8周Western blot检测骨折端组织血管内皮生长因子蛋白的表达分析结果显示,3组各时间点血管内皮生长因子表达的关系为：应用神经生长因子组>对照组>拮抗神经生长因子组(P < 0.05)。结果证实,在骨折愈合过程当中,应用神经生长因子可以促进血管内皮生长因子表达。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

常年变应性鼻炎黏膜中水通道蛋白1的表达及意义

水通道蛋白(aquaporin,AQP)是一组与水转运有关的细胞膜转运蛋白,广泛分布于机体组织细胞,尤其与液体分泌和吸收有关的上皮细胞和内皮细胞中含量丰富,参与水的分泌、吸收及细胞内外水的平衡.本实验通过免疫组化技术检测AQP1蛋白在常年变应性鼻炎鼻黏膜组织的表达及分布,探讨其与常年变应性鼻炎临床病理特征之间的关系.     

Expression of aquaporin-1 in endometrial blood vessels in menorrhagia

Aquaporin-1 (AQP1) is a water channel protein expressed in vascular endothelia and involved in impaired angiogenesis in tumors. Since angiogenesis is an essential component of the regeneration of the endometrium, we sought to analyze the expression of AQP1 in endometrial blood vessels in normal cyclic endometrium as well as in endometrial biopsies of menorrhagia patients. Endometrial biopsies from 16 patients with menorrhagia and 21 healthy fertile women were used for immunohistochemistry assessment of AQP1-stained endothelial structures. RT-PCR was used to confirm the presence of AQP1 mRNA. We detected the expression of AQP1 solely in endometrial blood vessels in the control group, as well as in menorrhagic endometrium. There was no difference between proliferative and secretory endometrium. Furthermore, we observed that the vascular expression of AQP1 in endometrial blood vessels in the menorrhagia group was significantly lower than in controls (p=0.002). There was also a significantly lower number of stained vessels per unit area in the menorrhagia group than in the controls (p=0.006). Thus, the deregulation of aquaporin-1 in menorrhagia may be involved in abnormal endometrial vascular growth and permeability.     

Chemokines, chemokine receptors and adhesion molecules on different human endothelia: discriminating the tissue-specific functions that affect leucocyte migration

The selective accumulation of different leucocyte populations during inflammation is regulated by adhesion molecules and chemokines expressed by vascular endothelium. This study examined how chemokine production and the expression of adhesion molecules and chemokine receptors vary between endothelia from different vascular beds. Human saphenous vein endothelium was compared with lung and dermal microvascular endothelia and with umbilical vein endothelium and a bone-marrow endothelial cell line. All endothelia produced CCL2 and CXCL8 constitutively, whereas CXCL10 and CCL5 were only secreted after tumour necrosis factor (TNF)-alpha or interferon (IFN)-gamma stimulation. In combination with TNF-alpha, IFN-gamma suppressed CXCL8 but enhanced CCL5 and CXCL10, whereas transforming growth factor (TGF)-beta reduced secretion of all chemokines. Basal chemokine secretion was higher from umbilical vein than other endothelial cells. Chemokine receptors, CXCR1, CXCR3 and CCR3, were present on all endothelia but highest on saphenous vein. CCR4, CCR5, CCR6, CXCR2, CXCR4 and CXCR5 were also detected at variable levels on different endothelia. The variation between endothelia in chemokine secretion was much greater than the variations in adhesion molecules, both on resting cells and following cytokine stimulation. These results indicate that it is the tissue-specific variations in endothelial chemokine secretion rather than variations in adhesion molecules that can explain the different patterns of inflammation and leucocyte traffic seen in non-lymphoid tissues.     

Clinical application of aquaporin research: aquaporin-1 in the peritoneal membrane

Peritoneal dialysis (PD) is an established mode of renal replacement therapy based on the exchange of fluid and solutes between blood and a dialysate that has been instilled in the peritoneal cavity. The dialysis process involves osmosis, as well as diffusive and convective transports through the highly vascularized peritoneal membrane. Computer simulations predicted that the membrane contains ultrasmall pores responsible for the selective transport of water across the capillary endothelium during crystalloid osmosis. The distribution of the water channel aquaporin-1 (AQP1), as well as its molecular structure ensuring an exquisite selectivity for water, fit with the characteristics of the ultrasmall pore. Peritoneal transport studies using AQP1 knockout mice demonstrated that the osmotic water flux across the peritoneal membrane is mediated by AQP1. This water transport accounts for 50% of the ultrafiltration during PD. Treatment with high-dose corticosteroids upregulates the expression of AQP1 in peritoneal capillaries, resulting in increased water transport and ultrafiltration in rats. AQP1 may also play a role during inflammation, as vascular proliferation and leukocyte recruitment are both decreased in mice lacking AQP1. These data illustrate the potential of the peritoneal membrane as an experimental model in the investigation of the role of AQP1 in the endothelium at baseline and during inflammation. They emphasize the critical role of AQP1 during PD and suggest that manipulating AQP1 expression could be clinically useful in PD patients.     

Chemokine transport across human vascular endothelial cells.

Leukocyte migration across vascular endothelium is mediated by chemokines that are either synthesized by the endothelium or transferred across the endothelium from the tissue. The mechanism of transfer of two chemokines, CXCL10 (interferon gamma-inducible protein [IP]-10) and CCL2 (macrophage chemotactic protein [MCP]-1), was compared across dermal and lung microvessel endothelium and saphenous vein endothelium. The rate of transfer depended on both the type of endothelium and the chemokine. The permeability coefficient (Pe) for CCL2 movement across saphenous vein was twice the value for dermal endothelium and four times that for lung endothelium. In contrast, the Pe value for CXCL10 was lower for saphenous vein endothelium than the other endothelia. The differences in transfer rate between endothelia was not related to variation in paracellular permeability using a paracellular tracer, inulin, and immunoelectron microscopy showed that CXCL10 was transferred from the basal membrane in a vesicular compartment, before distribution to the apical membrane. Although all three endothelia expressed high levels of the receptor for CXCL10 (CXCR3), the transfer was not readily saturable and did not appear to be receptor dependent. After 30 min, the chemokine started to be reinternalized from the apical membrane in clathrin-coated vesicles. The data suggest a model for chemokine transcytosis, with a separate pathway for clearance of the apical surface.     

Aquaporin water channels and endothelial cell function

The aquaporins (AQP) are a family of homologous water channels expressed in many epithelial and endothelial cell types involved in fluid transport. AQP1 protein is strongly expressed in most microvascular endothelia outside of the brain, as well as in endothelial cells in cornea, intestinal lacteals, and other tissues. AQP4 is expressed in astroglial foot processes adjacent to endothelial cells in the central nervous system. Transgenic mice lacking aquaporins have been useful in defining their role in mammalian physiology. Mice lacking AQP1 manifest defective urinary concentrating ability, in part because of decreased water permeability in renal vasa recta microvessels. These mice also show a defect in dietary fat processing that may involve chylomicron absorption by intestinal lacteals, as well as defective active fluid transport across the corneal endothelium. AQP1 might also play a role in tumour angiogenesis and in renal microvessel structural adaptation. However, AQP1 in most endothelial tissues does not appear to have a physiological function despite its role in osmotically driven water transport. For example, mice lacking AQP1 have low alveolar-capillary water permeability but unimpaired lung fluid absorption, as well as unimpaired saliva and tear secretion, aqueous fluid outflow, and pleural and peritoneal fluid transport. In the central nervous system mice lacking AQP4 are partially protected from brain oedema in water intoxication and ischaemic models of brain injury. Therefore, although the role of aquaporins in epithelial fluid transport is in most cases well-understood, there remain many questions about the role of aquaporins in endothelial cell function. It is unclear why many leaky microvessels strongly express AQP1 without apparent functional significance. Improved understanding of aquaporin-endothelial biology may lead to novel therapies for human disease, such as pharmacological modulation of corneal fluid transport, renal fluid clearance and intestinal absorption.     

The role of aquaporin-1 (AQP1) expression in a murine model of lipopolysaccharide-induced acute lung injury

A murine model of lipopolysaccharide (LPS)-induced acute lung injury (ALI) was used to evaluate whether aquaporin-1 (AQP1) is involved in lung inflammation and lung edema formation. Swiss strain mice (n = 122) had LPS (5 mg/kg) instilled intratracheally (IT), and were then treated with either 0.9 % saline or dexamethasone (5 mg/kg/day). Mice were euthanized at 2 days and 7 days after treatment. Inflammatory cytokines (TNF-alpha, IL-6), protein concentration in bronchoalveolar lavage (BAL) fluid, lung wet-to-dry weight ratio, histology, immunohistochemistry, and AQP1 Western blot were performed. Lung wet-to-dry weight ratio and lung vascular permeability were also measured in the AQP1 knockout mice (n = 9) that received IT LPS (5 mg/kg) at 2 days. Intratracheal instillation of LPS produced a severe lung injury at 2 days, characterized by elevation of TNF-alpha, IL-6 in the BAL fluid, and by histological changes consistent with increased lung vascular permeability and neutrophil infiltration. AQP1-immunoreactivity in the pulmonary capillary endothelium was reduced at 2 days and 7 days. Administration of dexamethasone improved LPS-induced ALI and retained expression of AQP1. However, depletion of AQP1 did not affect lung edema formation, lung vascular permeability, or lung histology. The results suggest that although AQP1 expression is decreased after lung injury, depletion of AQP1 does not alter lung inflammation and lung edema induced by LPS.     

Endothelial and smooth muscle cells express leukocyte adhesion molecules heterogeneously during acute rejection of rabbit cardiac allografts.

Interactions of leukocytes with vascular wall cells figure prominently in acute rejection and development of vascular occlusive disease after cardiac transplantation. To investigate the time course and distribution among different types of vessels of expression of endothelial leukocyte adhesion molecules, issues difficult to address in humans, we studied heterotopic transplants of Dutch-Belted rabbit hearts into New Zealand white recipients without immunosuppression (average time to graft failure 8.2 +/- 0.4 days). We found constitutive expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) by coronary arterial endothelium in normal rabbits, whereas myocardial capillaries and the endocardial lining cells showed little or no expression of VCAM-1. VCAM-1 expression increased within 1 day after transplantation on the endothelium of the transplanted aorta and endocardium and on myocardial microvascular endothelial cells. ICAM-1 expression increased remarkably on all endothelia studied from 2 to 8 days after transplantation. Adhesion molecule expression on coronary artery endothelial cells also increased during severe allograft rejection (from a histological score of 1.7 +/- 0.6 pretransplant to 4.8 +/- 0.2 8 days after transplant for VCAM-1 and from 0.9 +/- 0.6 to 4.4 +/- 0.3 for ICAM-1, n = 43 arteries in 5 animals, mean +/- SD). In addition, coronary artery and aortic smooth muscle cells also showed induction of VCAM-1 and ICAM-1 8 days after transplant. We conclude that endothelial activation in a transplanted organ can occur rapidly and varies among microvascular, endocardial, and coronary artery endothelial cells, a point germane to the interpretation of endomyocardial biopsies. Augmented expression of adhesion molecules precedes temporally leukocyte accumulation in vessels. In addition, our finding of activation of coronary artery smooth muscle cells during acute rejection suggests that such episodes may contribute to the development of accelerated coronary arteriosclerosis.     

Role of aquaporins in lung liquid physiology

Aquaporins (AQPs) are small, integral membrane proteins that facilitate water transport across cell membranes in response to osmotic gradients. Water transport across epithelia and endothelia in the peripheral lung and airways occurs during airway hydration, alveolar fluid transport and submucosal gland secretion. Several AQPs are expressed in the lung and airways: AQP1 in microvascular endothelia, AQP3 and AQP4 in airway epithelia, and AQP5 in type I alveolar epithelial cells, submucosal gland acini, and a subset of airway epithelial cells. Phenotype analysis of transgenic knockout mice lacking AQPs has defined their roles in the lung and airways. AQP1 and AQP5 provide the principal route for osmotically driven water transport between airspace and capillary compartments; however, alveolar fluid clearance in the neonatal and adult lung is not affected by their deletion, nor is lung fluid accumulation in experimental models of lung injury. In the airways, though AQP3 and AQP4 facilitate osmotic water transport, their deletion does not impair airway hydration, regulation of airway surface liquid, or fluid absorption. In contrast to these negative findings, AQP5 deletion in submucosal glands reduced fluid secretion by >50%. The substantially slower fluid transport in the lung compared to renal and secretory epithelia probably accounts for the lack of functional significance of AQPs in the lung and airways. Recent data outside of the lung implicating the involvement of AQPs in cell migration and proliferation suggests possible new roles for lung AQPs to be explored.     

Cellular localization of aquaporins along the secretory pathway of the lactating bovine mammary gland: An immunohistochemical study

In this study we examined the cellular localization of aquaporins (AQPs) along the secretory pathway of actively lactating bovine mammary glands using immunohistochemistry. Mammary tissues examined included secretory ducts and acini, gland cisterns, teats, stromal and adipose tissues. Aquaporin 1 (AQP1) was localized in capillary endothelia throughout the mammary gland in addition to myoepithelial cells underlying teat duct epithelia. AQP2 and AQP6 were not detected and AQP9 was found only in leukocytes. AQP3 and AQP4 were observed in selected epithelial cells in the teat, cistern and secretory tubuloalveoli. AQP5 immunopositivity was prominent in the cistern. AQP3 and AQP7 were found in smooth muscle bundles in the teat, secretory epithelial cells and duct epithelial cells. These immunohistochemical findings support a functional role for aquaporins in the transport of water and small solutes across endothelial and epithelial barriers in the mammary gland and in the production and secretion of milk.