Junctional plaque proteins shift to the apical surface of uterine epithelial cells during early pregnancy in the rat.

Antibodies against the cytoplasmic plaque molecules, plectin and plakoglobin, and cytokeratin, the molecular component of intermediate filaments (IFs), were used to examine the distribution of these molecules in rat uterine epithelial cells during early pregnancy including the period of blastocyst implantation. On day 1 of pregnancy plectin was detected in concentrated bands along the apical and basal plasma membranes, and diffusely throughout the cytoplasm. Plakoglobin was found along the entire lateral plasma membrane on day 1. By day 6, the time of blastocyst implantation, plectin was localised along the apical and basal membranes and reduced in the basal cytoplasm, and plakoglobin was seen exclusively at the apical-most quarter of the lateral plasma membrane. Cytokeratin was detected throughout the cytoplasm on day 1, but by day 6, was localised to the apical region of the cytoplasm only. These results show a redistribution of plectin, plakoglobin and cytokeratin away from the basal region of the uterine epithelial cells. The change in distribution of these molecules may contribute to the adhesion of the blastocyst to the apical and lateral surfaces of uterine epithelial cells and the subsequent detachment of the uterine epithelium from the basal lamina.     

Aberrant expression of tight junction-related proteins ZO-1, claudin-1 and occludin in synovial sarcoma: an immunohistochemical study with ultrastructural correlation.

Synovial sarcoma demonstrates epithelial differentiation, either by light microscopy (biphasic synovial sarcoma) or by immunohistochemical/ultrastructural methods only (monophasic) and poorly differentiated synovial sarcoma. Although the glands of synovial sarcoma are known to have tight junction-like structures, far less is known about junction formation in the spindled component of synovial sarcomas. Additionally, it is unknown whether the tight junctions of synovial sarcoma are normally constituted. The tight junction is a multiprotein complex consisting of numerous proteins that include ZO-1, claudin-1 and occludin. A total of 35 cases of synovial sarcoma (13 biphasic, 14 monophasic and eight poorly differentiated) were immunostained for ZO-1, claudin-1 and occludin using commercially available antibodies, heat-induced epitope retrieval and standard avidin-biotin technique. When available, corresponding electron micrographs were reviewed. For five cases, the presence of either an SYT-SSX1 (three cases) or SYT-SSX2 (two cases) gene fusion was known. Positive cases showed particulate membrane staining. The glands of biphasic synovial sarcomas expressed ZO-1 (13/13), claudin-1 (12/13) and occludin (11/13) in a manner identical to normal glandular epithelia, at the apical portion of the lateral membrane. The spindle cells of biphasic synovial sarcomas showed abnormal circumferential membranous expression of ZO-1 (12/13), claudin-1 (6/13) and occludin (3/13). Monophasic synovial sarcomas expressed ZO-1 in a circumferential pattern (13/14) but less often claudin-1 (4/14) or occludin (3/14). Poorly differentiated synovial sarcomas expressed ZO-1 (8/8) and claudin-1 (6/8) but only rarely occludin (2/8). By electron microscopy, recognizable tight junctions were seen only in glands. No correlation was seen between histologic subtype or fusion type and expression of tight junction proteins. We conclude that the glands of biphasic synovial sarcomas show well-organized, true epithelial tight junctions. In contrast, the spindled cells of all synovial sarcomas show significant abnormalities in the expression and localization of tight junction proteins, suggesting partial and/or aberrant epithelial differentiation.     

Amyloid beta-peptide1-42 alters tight junction protein distribution and expression in brain microvessel endothelial cells

Alzheimer's disease is characterised by neuronal loss, numerous intraneuronal deposits of neurofibrillary tangles, senile plaques, and cerebrovascular amyloid deposits. The major component of senile plaques and cerebrovascular deposits is the 39-43 amino acid beta-amyloid peptide (Abeta). The effects of Abeta on cerebral endothelium and thus the blood-brain barrier remain unclear. Utilising endothelial cells isolated from rat cerebral cortex microvessels, we have examined effects of Abeta peptides on tight junction protein behaviour. The transmembrane tight junction proteins occludin, claudin-1 and claudin-5, as well as the cytoplasmic accessory proteins ZO-1 and ZO-2 displayed a continuous distribution at cell boundaries. Endothelial cells exposed to Abeta1-42 (20 microM) for 3 days showed a disrupted plasma membrane pattern of claudin-5 and ZO-2 with relocation to the cytoplasm. These effects were not seen with Abeta25-35 or Abeta1-40[Gln22] (Dutch type). Abeta1-42 treatment altered also protein expression: occludin was lower at 1st day, claudin-1 increased at all times, and ZO-2 increased after 1 day and then decreased. These data suggest that Abeta1-42 effects on tight junction protein complexes may alter blood-brain barrier integrity and contribute to the neuropathological sequelae of Alzheimer's disease.     

Different changes in the expression of multiple kinds of tight-junction proteins during ischemia-reperfusion injury of the rat ileum

Dysfunction of tight junctions (TJs), located at the most apical part of the intestinal epithelium, is believed to result in various complications in intestinal disease. However, the behaviors of multiple kinds of TJ proteins during ischemia-reperfusion injury are not understood in detail. To determine changes in expression and localization of TJ proteins during intestinal-barrier recovery, we induced intestinal ischemia-reperfusion injury in rats, measured mucosa-to-blood permeability of fluorescein isothiocyanate-dextran-4 kDa, and compared it with spatiotemporal changes of ZO-1, occludin, and claudin-1, -2, -3, -4, and -5 by immunoconfocal microscopy. At 1 hour post-reperfusion, villi were denuded and intestinal-barrier function was lost. From 6 to 24 hours post-reperfusion, villous epithelium was restored by cell migration, and barrier function together with reticular pattern expression of ZO-1, occludin, and claudin-1, -3, and -5, recovered time-dependently. To the contrary, after ischemia-reperfusion injury, the localized expression of claudin-2 and claudin-4 observed in the non-treated control was lost and replaced with broader expression from crypts to villi with increased basolateral claudin-4 expression in epithelial cells. These data demonstrated that recovery of intestinal barrier function is associated with expression of ZO-1, occludin, and claudin-1, -3, and -5, whereas claudin-2 and claudin-4 show unique changes in expression and localization.     

Acid modulates the squamous epithelial barrier function by modulating the localization of claudins in the superficial layers

Acid is a major cause of gastro-esophageal reflux disease. However, the influence of acid on the esophageal stratified epithelial barrier function and tight junction (TJ) proteins is not fully understood. Here, we explore the influence of acid on barrier function and TJ proteins using a newly developed model of the esophageal-like squamous epithelial cell layers that employs an air-liquid interface (ALI) system. Barrier function was determined by measuring trans-epithelial electrical resistance (TEER) and diffusion of paracellular tracers. TJ-related protein (claudin-1, claudin-4, occludin and ZO-1) expression and localization was examined by immunofluorescent staining, and by western blotting of 1% NP-40 soluble and insoluble fractions. We also examined the influence of acid (pH 2-4) on the barrier created by these cells. The in vitro ALI culture system showed a tight barrier (1500-2500 Ω·cm(2)) with the expression of claudin-1, claudin-4, occludin and ZO-1 in the superficial layers. Claudin-1, claudin-4, occludin and ZO-1 were detected as dots and whisker-like lines in the superficial layers, and as a broad line in the suprabasal layers. These localization patterns are similar to those in the human esophagus. On day 7 under ALI culture, TJ proteins were detected in the superficial layers with functional properties, including decreased permeability and increased TEER. Dilated intercellular spaces were detected at the suprabasal cell layers even under the control conditions of ALI cells. pH 2 acid on the apical side significantly reduced the TEER in ALI-cultured cells. This decrease in TEER by the acid was in parallel with the decreased amount of detergent-insoluble claudin-4. Claudin-4 delocalization was confirmed by immunofluorescent staining. In conclusion, TJs are located in the superficial layers of the esophagus, and acid stimulation disrupts barrier function, at least in part by modulating the amount and localization of claudin-4 in the superficial layers.     

Ultrastructural localisation of Muc-1 on the plasma membrane of uterine epithelial cells

The presence and distribution pattern of Muc-1 was determined immunohistochemically in rat uterine epithelial cells and localised ultrastructurally on the plasma membrane of uterine epithelial cells. Rat uterine tissue was examined on days 1, 3 and 6 of pregnancy and it is shown to be expressed in uterine luminal epithelial cells on day 1 of pregnancy with decreasing expression towards the time of implantation on day 6. It was demonstrated ultrastructurally that Muc-1 is expressed at the external surface of the plasma membrane of uterine epithelial cells thus confirming that it is well positioned to act as an anti-adhesive molecule during the nonreceptive stage of pregnancy. Ultrastructural localisation also revealed that Muc-1 was not present on the outer surface of the plasma membrane during the receptive phase.     

Expression of occludin, tight-junction-associated protein, in human digestive tract.

The tight junction seals cells together at a subapical location and functionally separates the plasma membrane into an apical and a basolateral domain. This junction is one of the most characteristic structural markers of the polarized epithelial cell. Recently, occludin has been identified as an integral transmembrane protein localizing at the tight junction and directly associated with ZO-1, an undercoat-constitutive cytoplasmic protein. We have investigated occludin expression in conjunction with ZO-1 in normal epithelia and cancers of human digestive tract by immunostaining with a new antibody raised against human occludin. In the normal simple columnar epithelium, occludin was expressed together with ZO-1 as a single line at the apical cell border. However, in the esophagus, which has a stratified squamous epithelium, no occludin expression could be detected, but ZO-1 was expressed in the spinous layer. As for cancers, both occludin and ZO-1 showed the same expression in differentiated adenocarcinoma cells as in normal epithelium, but in poorly differentiated adenocarcinomas, the expression of these two proteins was reduced. There was significant correlation between tumor differentiation and expression of these proteins. These results suggest that occludin, together with ZO-1, is involved in the formation of gland-like structures. In addition, occludin expression can serve as a histopathological indicator for differentiation in gastrointestinal adenocarcinomas.     

Progesterone treatment and the progress of early pregnancy reduce desmoglein 1&2 staining along the lateral plasma membrane in rat uterine epithelial cells

Uterine epithelium undergoes dramatic changes during early pregnancy in preparation for implantation. We have studied distribution patterns of the desmosomal marker, desmoglein 1&2, in rat uterine epithelial cells during early pregnancy as well as in hormonally stimulated ovariectomised animals. On day 1 of pregnancy as well as in oestradiol treated rats, desmoglein 1&2 staining was localized along the entire length of the lateral plasma membrane. By day 3 and on subsequent days of pregnancy as well as in ovariectomised animals treated with progesterone alone or in combination with oestradiol, desmoglein 1&2 staining was concentrated at the apical portion of the lateral plasma membrane. We suggest that the reorganisation of these desmosomal cadherins is an important component of uterine epithelial receptivity and this relocation is under the control of the ovarian hormone progesterone.     

Cytoskeletal proteins in uterine epithelial cells only partially return to the pre-receptive state after the period of receptivity

Immunohistochemical staining of 5 cytoskeletal proteins (actin, alpha-actinin, gelsolin, plectin and plakoglobin) was used to investigate changes in distribution patterns of these proteins after the period of uterine receptivity for blastocyst implantation in the rat. Actin was found throughout the cytoplasm but it was concentrated along the apical plasma membrane on day 1 of pregnancy, decreased by day 6 and then increased again at day 9. Alpha-actinin and gelsolin were localized in distinctive bands along the apical plasma membrane at day 6 of pregnancy but became diffusely distributed at day 9. Plectin was localized along the apical and basal plasma membranes at day 6 but in higher amounts apically and at day 9, it was concentrated in apical and basal zones in the cells. Plakoglobin was found along the lateral and basal membranes with increased intensity along the apical third of the lateral plasma membrane from day 6 to day 9 of pregnancy. These results show that all 5 cytoskeletal proteins redistributed after the period of uterine receptivity: some exhibited a similar pattern of labelling to that found during the prereceptive state, whereas others only partially returned to the pre-receptive state. This change in distribution patterns may reflect differences in the epithelial barrier function before and after the period of receptivity.     

IL-8对血管内皮细胞紧密连接的影响

目的 研究白细胞介素-8(IL-8)对血管内皮细胞紧密连接的影响.方法 采用免疫荧光染色检测经不同浓度和时间IL-8处理后EA.hy926细胞的3种紧密连接蛋白occludin、claudin-5和ZO-1的形态和分布;逆转录PCR(RT-PCR)检测3种蛋白mRNA的表达水平.结果 IL-8可改变内皮细胞紧密连接蛋白...     

Immunolocalization of occludin and claudin-1 to tight junctions in intact CNS vessels of mammalian retina

The distributions of occludin and claudin-1, two tight junction–associated integral membrane proteins were investigated by immunohistochemical analysis of whole-mount preparations of the blood vessels in the myelinated streak of the rabbit retina. Light microscopy revealed that occludin and claudin-1 immunoreactivities were abundant along the interface of adjacent endothelial cells of all blood vessels. Electron microscopy revealed that both proteins were distributed in a regular pattern (at regular intervals of approximately 80 nm) along the length of tight junctions, probably in the regions of tight junction strands. No other structures or cell types expressed either of these two proteins in the myelinated streak. Whereas occludin immunoreactivity was concentrated only at the tight junction interface, claudin-1 immunoreactivity also extended into the cytoplasm of the endothelial cells, suggesting a different structural role for claudin-1 than for occludin at tight junctions. Retinal pigment epithelial cells expressed occludin around their entire circumference, consistent with the function of these cells as a barrier separating the retina from the leaky vessels of the choroid. Also consistent with the association of occludin expression with vessels that exhibit functional tight junctions, this protein was expressed at only a low level in, and showed an irregular distribution along, the vessels of the choroid, a vascular bed that lacks blood-barrier properties. Further, the distribution of occludin was examined during formation and remodelling of the rat retinal vasculature. Occludin expression was evident at the leading edge of vessel formation and was found on all vessels in both the inner and outer vascular plexus. Numerous vascular segments at the early stage of vascular formation and regression lost occludin expression. The biological significance of this transient loss of occludin expression in terms of barrier function remains to be elucidated.     

Immunohistological study of tight junction protein expression in mal de Meleda

Mal de Meleda (MdM, MIM: 248300) is a rare autosomal recessive skin disorder characterized by diffuse palmoplantar keratoderma and transgressive keratosis with onset in early infancy. The gene responsible for MdM, ARS, encodes for Secreted Lys6/Plaur domain-containing protein 1 which is essential for epidermal homeostasis. Tight junctions have been proposed to have two mutually exclusive functions: a fence function which prevents the mixing of membrane proteins between the apical and basolateral membranes; and a gate function which controls the paracellular passage of ions and solutes between cells. In this study we report immunohistochemical investigations of tight junction proteins claudin-1 and occludin in MdM Tunisian families. Nine skin biopsies from patients with MdM were analyzed. The control group was formed by skin biopsies belonging to healthy individuals. Immunohistochemical study was performed on fixed sections from biopsies of four microns with the following polyclonal antibodies: anti-claudin-1 and anti-occludin. In control skin, claudin-1 exhibited membrane expression throughout the epidermis with increasing and upward intensity, whereas occludin was detected in the cell membrane of keratinocytes of the stratum granulosum. In MdM skin, claudin-1 was expressed throughout the thickness of the spinous layers with membrane staining, and occludin had cytoplasmic staining in the granular layer. The immunohistochemical expression of TJ proteins in MdM patients harbors premature expression of occludin and decreased expression of claudin-1, highlighting further evidence for disorders in epidermal homeostasis.     

Expression of ZO-1 and occludin in normal human placenta and in hydatidiform moles

Zonula occludens-1 (ZO-1) and occludin are key molecules in cell-cell contacts. They are tight junction constituents and therefore play a pivotal role in tissue differentiation and organogenesis. In the present report we have investigated the expression of ZO-1 and occludin in normal human placentae and in hydatidiform moles using immunohistochemical and Western blot analyses. In normal placentae, ZO-1 and occludin were mainly localized in the apical part of the syncytium, in cell-cell contacts between syncytium and villous cytotrophoblastic cells as well as between the latter. Extravillous cytotrophoblast of cell islands and cell columns was positive for ZO-1 and occludin in the cell layers proximally located to the villous stroma whereas the cytotrophoblastic cells, distally located from the villous stroma, were totally negative. Furthermore, fetal vessels showed a positive staining pattern for ZO-1 throughout gestation, whereas a positive reaction for occludin was produced mainly at term. A striking result was the altered expression of ZO-1 and occludin in partial and complete moles. In 11 moles, these two molecules were not expressed at all, while in the other nine, their expression was only cytoplasmic in syncytium and villous cytotrophoblastic cells. These findings suggest that ZO-1 and occludin participate in normal placental development, maintaining the organization and functions of different tissue components. The down-regulation and/or dysregulation of these two molecules may be related to phenotypic changes associated with epithelial cell transformation of the chorionic villi in partial and complete moles.     

帕金森病模型大鼠十二指肠黏膜紧密连接蛋白表达下调

目的研究紧密连接蛋白在6-羟多巴(6-OHDA)制备的帕金森病(PD)大鼠模型十二指肠黏膜的表达变化。方法用6-OHDA损毁双侧中枢黑质多巴胺能神经元建立大鼠模型。用免疫荧光组织化学和蛋白免疫印迹检测紧密连接蛋白claudin-1、occludin和ZO-1肠黏膜的定位和表达。结果紧密连接蛋白claudin-1、occludin和ZO-1在PD大鼠模型十二指肠黏膜上均有表达,但仅ZO-1(P0.001)和occludin(P0.01)表达明显下调,而claudin-1无显著变化。结论 PD大鼠模型十二指肠黏膜紧密连接蛋白ZO-1、occludin的表达显著下调,可能与帕金森病十二指肠溃疡的发生发展相关。     

Epithelial cadherin disassociates from the lateral plasma membrane of uterine epithelial cells throughout pregnancy in a marsupial

The uterine luminal epithelium is the first site of contact between fetal and maternal tissues during therian pregnancy and must undergo specialised changes for implantation of the blastocyst to be successful. These changes, collectively termed the plasma membrane transformation (PMT), allow the blastocyst to attach to the uterine epithelium preceding the formation of a placenta. There are similarities in the morphological and molecular changes occurring in live‐bearing eutherian species during the PMT studied so far. Similar cellular remodelling occurs in a marsupial species, the fat‐tailed dunnart (Sminthopsis crassicaudata), despite the divergence of marsupials from eutherian mammals over 130 mya, which resulted in the evolution of distinct reproductive strategies. Adhesion molecules along the lateral plasma membrane of uterine epithelium provide a barrier to invasion by the embryo. We thus characterised the presence and change in distribution of epithelial cadherin (E‐cadherin) in uterine epithelium from non‐pregnant fat‐tailed dunnarts and compared it to dunnarts in early‐, mid‐ and late‐stage pregnancy. E‐cadherin staining is localised to the lateral plasma membrane in uterine epithelium from non‐pregnant and early‐stage pregnant dunnarts. The E‐cadherin staining is cytoplasmic in epithelium from uteri of mid‐ and late‐stage pregnant dunnarts. This loss of localised staining suggests that the adherens junction dissociates from the lateral plasma membrane, allowing for invasion between the epithelial cells by the blastocyst. As the changes during pregnancy to cadherin were similar in the laboratory rat with highly invasive (haemochorial) placentation, a live‐bearing lizard species with non‐invasive (epitheliochorial) placentation and a marsupial, the fat‐tailed dunnart, which has invasive (endotheliochorial) placentation, we suggest that the molecular mechanisms allowing for successful pregnancy are conserved among mammals during the early stages of pregnancy regardless of placental invasiveness.     

Claudin-1 is a strong prognostic indicator in stage II colonic cancer: a tissue microarray study.

Tight junction associated proteins are key molecular components governing cellular adhesion, polarity and glandular differentiation. Tight junction proteins also play critical roles in cellular proliferation and neoplastic pathways via their functions as couplers of the extracellular milieu to intracellular signaling pathways and the cytoskeleton. Neoplastic cells frequently exhibit structural and functional deficiencies in the tight junction. The purpose of this study was to determine the pattern of expression and prognostic value of four tight junction associated proteins, claudin-1, claudin-4, occludin and ZO-1 in a cohort of TNM stage II colon cancer using tissue microarray technology. In this study, we retrospectively analyzed, resected and otherwise untreated paraffin embedded specimens from 129 consecutive patients with TNM stage II colonic carcinomas for claudin-1, claudin-4, occludin and ZO-1 protein expression by immunohistochemistry. Seventy-five, 58, 56 and 44% of the tumors exhibited normal to elevated expression levels (+2 and +3 immunopositivity) of claudin-1, claudin-4, occludin and ZO-1 respectively. Low expression levels of claudin-1 and ZO-1 were directly associated with higher tumor grade (P=0.05 and 0.03 respectively). Multivariate analysis indicated that lymphovascular invasion (P=0.01) and low levels of claudin-1 (P=0.0001) expression were independent predictors of recurrence and that reduced claudin-1 expression (P=0.0001) was associated with poor survival. This study is the first to comprehensively examine the expression of several tight junction associated proteins in colonic neoplasms and to correlate their expression with disease progression. Loss of claudin-1 expression proved to be a strong predictor of disease recurrence and poor patient survival in stage II colon cancer.     

Neutrophil Transmigration in Inflammatory Bowel Disease Is Associated with Differential Expression of Epithelial Intercellular Junction Proteins

Inflammatory bowel disease (IBD) consisting of ulcerative colitis (UC) and Crohn's (CD) typically displays a waxing and waning course punctuated by disease flares that are characterized by transepithelial migration of neutrophils (PMN) and altered barrier function. Since epithelial barrier function is primarily regulated by the apical most intercellular junction referred to as the tight junction (TJ), our aim was to examine expression of TJ and adherens junction (AJ) proteins in relation to PMN infiltration in mucosal tissue samples from patients with active IBD. Expression of epithelial intercellular TJ proteins (occludin, ZO-1, claudin-1, and JAM) and subjacent AJ (beta-catenin and E-cadherin) proteins were examined by immunoflourescence/confocal microscopy, immunohistochemistry, and Western blotting. Colonic mucosa from patients with UC revealed dramatic, global down-regulation of the key TJ transmembrane protein occludin in regions of actively transmigrating PMN and in quiescent areas in the biopsy samples. Significant decreases in occludin expression were observed at the protein and mRNA levels by Western and Northern blotting. In contrast, expression of other TJ and AJ proteins such as ZO-1, claudin-1, JAM, beta-catenin, and E-cadherin were down-regulated only in epithelial cells immediately adjacent to transmigrating PMN. Analysis of inflamed mucosa from Crohn's disease patients mirrored the results obtained with UC patients. No change in TJ and AJ protein expression was observed in colonic epithelium from patients with collagenous colitis or lymphocytic colitis that are respectively characterized by a thickened subepithelial collagen plate and increased intraepithelial lymphocytes. These results suggest that occludin expression is diminished in IBD by mechanisms distinct from those regulating expression of other intercellular junction proteins. We speculate that down-regulation of epithelial occludin may play a role in enhanced paracellular permeability and PMN transmigration that is observed in active inflammatory bowel disease.     

Tight junctions in differentiating ameloblasts and odontoblasts differentially express ZO-1, occludin, and claudin-1 in early odontogenesis of rat molars

Little is known about the expression of associated proteins during the assembly of tight junctions (TJs). We studied the distribution of ZO-1, occludin, and claudin-1 between differentiating ameloblasts and odontoblasts in molar tooth germs from 1- to 3-day-old rats by confocal laser scanning microscopy. Immunoreactivity for ZO-1 was strong at proximal and distal junctional complexes of differentiating ameloblasts, while it was weak and punctuate at the distal region of differentiating odontoblasts. Occludin was immunoreactive at distal and proximal complexes of early differentiating ameloblasts and at distal regions of differentiating odontoblasts. However, in more advanced stages, occludin was only evident at the proximal complex of ameloblasts. Claudin-1 was strongly detected at the proximal complex but it was weak at distal complex of late differentiating ameloblasts. Thus, our results showed that ZO-1, occludin, and claudin-1 are differentially expressed as TJs assemble for regulating polarity and/or paracellular permeability in differentiating ameloblasts and odontoblasts.     

siRNA-Tie1下调紧密连接相关蛋白claudin-5、occludin和ZO-1增加血肿瘤屏障通透性

目的研究Tie1 AS和Tie1表达变化对血肿瘤屏障通透性的影响和相关机制。方法建立体外血脑屏障和血肿瘤屏障模型,Real-time PCR检测h CMEC/D3细胞中Tie1 AS和Tie1的表达水平。转染p IRES2-EGFPTie1 AS表达载体上调体外血肿瘤屏障模型h CMEC/D3细胞中Tie1 AS的表达,Western blot检测Tie1的表达变化。将si RNA-Tie1转染人h CMEC/D3细胞并建立体外血肿瘤屏障模型,跨内皮电阻测量系统分析血肿瘤屏障通透性变化;Western blot和免疫荧光法检测h CMEC/D3细胞中紧密连接相关蛋白claudin-5、occludin和ZO-1的表达和分布变化。结果和正常脑微血管内皮细胞相比,体外血肿瘤屏障模型h CMEC/D3细胞中Tie1的表达显著增加,而Tie1 AS的表达显著降低。上调体外血肿瘤屏障模型内皮细胞中Tie1 AS的表达水平,能够显著降低Tie1的表达。下调体外血肿瘤屏障模型内皮细胞中Tie1的表达后屏障通透性显著下降,伴有claudin-5、occludin和ZO-1的表达下调以及在细胞膜上呈不连续分布。结论体外血肿瘤屏障模型内皮细胞中低表达的Tie1 AS能够负性调控Tie1的表达,进而通过调节紧密连接相关蛋白的表达和分布影响屏障的通透性。