Altered levels of immune cell adhesion molecules are associated with memory impairment in schizophrenia and healthy controls

Increased cytokines and increased intercellular adhesion molecule-1 (ICAM1) found in the schizophrenia prefrontal cortex and in the blood may relate to cognitive deficits. Endothelial ICAM1 regulates immune cell trafficking into the brain by binding to integrins located on the surface of leukocytes. Whether the circulating levels of the main ICAM1 adhesion partners, lymphocyte-function associated antigen-1 (LFA1) and complement receptor 3 (CR3), both integrins, are altered in schizophrenia is unknown. Gene expressions of ICAM1, LFA1 and CR3 were measured in leukocytes from 86 schizophrenia patients and 77 controls. Participants were also administered cognitive testing to determine the extent to which cognitive ability was related to molecular measures of leukocyte adhesion. This cohort was previously stratified into inflammatory subgroups based on circulating cytokine mRNAs; thus, gene expressions were analysed by diagnosis and by inflammatory subgroups. Previously measured plasma ICAM1 protein was elevated in “high inflammation” schizophrenia compared to both “high” and “low inflammation” controls while ICAM1 mRNA was unchanged in leukocytes. LFA1 mRNA was decreased and CR3 mRNA was increased in leukocytes from people with schizophrenia compared to controls. LFA1 mRNA levels were positively correlated with working memory and elevated soluble ICAM1 was negatively correlated with verbal memory in schizophrenia. Altogether, some of the cognitive deficits in schizophrenia may be associated with altered expression of molecules that regulate immune cell trafficking.     

Activation and adhesion molecule expression on lymphoid infiltrates in human glioblastomas

Frozen tissue sections obtained from human glioblastomas, brain tumor metastases and normal brain were examined for the expression of molecules known to be involved in lymphocyte activation and/or adhesion and migration. The molecules studied included CD3, CD45R, UCHL-1 (CD45RO), lymphocyte function-associated antigen 1 (LFA-1) (CD11a, CD18), intercellular adhesion molecule 1 (ICAM-1) (CD54), 4B4 (CD29), CD44, CD2, and LFA-3 (CD58). CD3+ lymphocytes infiltrating human glioblastomas and brain tumor metastases expressed LFA-1 alpha and beta. Many cells were also UCHL-1+ whereas only a small percentage were CD45R+. CD2+ lymphocytes were also present. Tumor-infiltrating lymphocytes (TIL) were found to be negative for CD29, which was, however, expressed on intratumoral vessels in addition to vessels found in normal brain. Glioblastoma cells and intratumoral vessels expressed ICAM-1 whereas no ICAM-1 was found on TIL or on normal brain. Glioblastoma cells also expressed high levels of both CD44 and LFA-3 whereas TIL were negative for these antigens. CD44 was also expressed on certain regions of normal brain. Antibodies to LFA-1 alpha and -beta and ICAM-1 could significantly block the binding of lymphokine-activated killer (LAK) cells or TIL to human glioblastoma cells suggesting that these molecules play a role in the binding and subsequent migration of lymphocytes into brain tumor tissue.     

Adhesion molecule expression on cerebrospinal fluid T lymphocytes: Evidence for common recruitment mechanisms in multiple sclerosis,aseptic meningitis,and normal controls

The expression of T-cell surface antigens was investigated in the cerebrospinal fluid (CSF) and peripheral blood of 11 patients with multiple sclerosis, 6 patients with aseptic meningitis, and 16 healthy subjects. A panel of monoclonal antibodies to adhesion and activation proteins was used in combination with an anti-CD3 antibody in dual-color flow cytometry. The problem of low cell numbers in the CSF from normal individuals was overcome by use of a modified staining procedure in microtiter plates, enabling analysis of as few as 5,000 cells. The majority of T cells in the CSF of the three patient groups exhibited the phenotype of memory cells (CD45RO⁺). CSF T cells also expressed significantly higher levels of several adhesion and activation molecules, including very late activation (VLA) antigens 3 through 6, lymphocyte function-associated (LFA) antigen 1, LFA-3, CD2, CD26, and CD44. Comparison between the different categories revealed that peripheral blood T cells from patients with multiple sclerosis expressed significantly lower amounts of the VLA integrins 4 and 5 as well as their common β subunit CD29, compared with normal control subjects. No differences between patients with multiple sclerosis and control subjects could, however, be seen regarding the distribution of memory/naive cells or CD4⁺/CD8⁺ cells in peripheral blood. Our data support a hypothesis that memory T cells with a high expression of several adhesion molecules are selectively recruited to the central nervous system compartment, under both pathological and normal conditions. We also provide evidence for an altered expression of adhesion molecules on peripheral blood T cells in patients with multiple sclerosis that is independent of the memory cell phenotype as defined by the expression of the CD45RO epitope.     

Expression of cell adhesion molecules by microvascular endothelial cells in the cortical and subcortical regions of the normal human brain: an immunohistochemical analysis

We studied the repertoire of junctional, cell–matrix and leucocyte–endothelial adhesion molecules normally expressed by cortical and subcortical brain microvessels, as compared with large intracranial vessels. An indirect immunoperoxidase method was applied to acetone‐fixed cryostat sections of normal brain tissue obtained from 10 adult patients during surgical resections for intracranial aneurysms or at autopsy. Like large intracranial vessels, brain microvessels expressed the two endothelial‐specific junctional cell adhesion molecules VE‐cadherin and platelet–cell adhesion molecule‐1. We verified that they also expressed the molecular components of adherens‐type junctions, including catenins, plakoglobin, vinculin and α‐actinin. Brain microvessels expressed a large repertoire of integrin molecules of the β1, β3 and β4 subfamilies. However, they displayed apparently lower levels of α2, α5, αV and β3 integrin chains than large intracranial vessels. Brain microvessels constitutively expressed large amounts of the leucocyte–endothelial adhesion molecules, intercellular adhesion molecule (ICAM)‐2 and CD34 and very low amounts of ICAM‐1 and lymphocyte function‐associated antigen‐3. In contrast to large intracranial vessels, brain microvessels presented no constitutive expression of P‐selectin. Our study shows that, in contrast to their highly specific structural and functional characteristics, brain microvascular endothelial cells present a repertoire of cell adhesion molecules very similar to that of most other capillary vessels in the body.     

Differential expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in chronic murine retroviral encephalitis

The cell adhesion molecules, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1, are important mediators of immune interactions within the central nervous system (CNS). A wide variety of pro-inflammatory insults to the brain, including viral infection, result in upregulation of these molecules on brain endothelial cells, astrocytes, and microglia. This study investigated the expression of ICAM-1 and VCAM-1 in chronic encephalitis induced by infection with a temperature sensitive (ts-1) strain of Moloney murine leukaemia virus (MoMuLV), an ecotropic murine retrovirus. During the late stages of disease, viral antigen was present in both endothelial cells and microglia, but not astrocytes, in regions of spongiform change and gliosis. In these areas, ICAM-1 staining was detected on activated microglia, but not on endothelial cells or astrocytes. In contrast, no cells showed increased VCAM-1 expression in the CNS. These findings demonstrate that there is cell-specific, differential expression of these adhesion molecules in ts-1 retroviral encephalitis. The lack of endothelial cell expression correlates with the characteristic lack of lymphocytic infiltrate in this chronic retroviral encephalitis and suggests that increased microglial ICAM-1 expression may play a role in the pathogenesis of MoMuLV (ts-1)-mediated neurodegeneration.     

Cell‐adhesion molecules in human meningiomas: correlation with clinical and morphological data

Integrins form a family of cell adhesion molecules. CD44 glycoproteins are found in a wide variety of isoforms; the most common, CD44s (standard) is widely distributed, and functions as an adhesion molecule. In this study, we have investigated immunohistochemically the distribution of some VLA integrins (α2, α5 and α6 chains of β1 integrins) and CD44s in 44 meningioma specimens and normal arachnoid villi. Meningiomas were of meningothelial (16), transitional (13) and fibroblastic (15) subtypes. There were 13 grade I, 19 grade II and 12 grade III (27%). Immunoprecipitates were quantified by image analysis and correlated with clinical (age, sex, location) and morphological data (histological subtypes and grades). VLA α5 chain was expressed by normal arachnoid villi (mainly cap cells) and by 42 out of 44 meningioma specimens. Expression was lower in fibroblastic meningiomas (P=0.02). VLA α2 and α6 chains were not observed in normal arachnoid villi. VLA α2 was expressed by 15 meningiomas, VLA α6 by 10. Interestingly, meningiomas expressing either VLA α2 or α6 were usually of grade III (P≤0.05). CD44s was found on various parts of arachnoid villi and in all meningiomas although expression was higher in meningothelial and transitional than in fibroblastic (P≤0.001). These results show that VLA α5 and CD44s are widely expressed by arachnoid villi and meningiomas, in contrast to VLA α2 and VLA α6. It was noted that high grade meningiomas (III) express VLA α2 and α6 suggesting that changes in integrin pattern expression are a feature of these meningiomas. Moreover, strong CD44s expression characterizes meningothelial and transitional meningiomas. Previous studies have shown that high NCAM expression is a feature of fibroblastic meningiomas whereas meningothelial and transitional meningiomas expressed mainly E-Cadherin, and that polysialylated NCAM expression was restricted to high grade meningiomas. Taken together these features suggest that each cell adhesion molecule has a characteristic pattern of expression according to meningioma subtype and grade. No correlation was seen between integrins and CD44s expression and clinical data.     

Regulation of leukocyte function-associated antigen 1-mediated adhesion by somatostatin and substance P in mouse spleen cells

BACKGROUND: Interaction of the integrin leukocyte function-associated antigen (LFA)-1 (CD11a/CD18) with its ligands, the intercellular adhesion molecules (ICAM)-1, -2, and -3 (CD54, CD102, and CD50), is pivotal to many leukocyte adhesion events. METHOD: To define the mechanism of the movement of leukocytes to the inflammatory site by somatostatin (SOM) and substance P (SP), we examined the expression of the adhesion molecule LFA-1 and inside-out signals for integrins, protein kinase C (PKC), Ras, Rap1, and phosphoinositide (PI) 3-kinase, in anti-CD3-, anti-CD3+SOM-, anti-CD3+SP-stimulated or unstimulated spleen cells. RESULTS: SOM caused down-regulation of LFA-1 mRNA translation as well as of adhesion-stimulating molecules such as Rap1, Ras, and PI 3-kinase. On the other hand, SP slightly induced LFA-1 mRNA translation and activation signals for integrins. The early-phase alteration of LFA-1 mRNA translation after 3 h of culture may be due to the changes of CD8+ T cells rather than changes of CD4+ cells. In adhesion assays, SOM significantly decreased cell adhesion (p < 0.05). CONCLUSION: These data suggest that SOM treatment of spleen cells, especially in CD8+ T cells, leads to downregulation of LFA-1 mRNA translation, inside-out signaling molecules for integrins (Ras, Rap1 and PI 3-kinase, but not PKC), and consequently to a decrease in the LFA-1-mediated adhesion to ICAM-1.     

Expression of transforming growth factor (TGF)-beta1, -beta2, and -beta3 isoforms and TGF-beta type I and type II receptors in multiple sclerosis lesions and human adult astrocyte cultures

It is known that the pleiotropic cytokine transforming growth factor beta (TGF-beta) has a regulatory role in the process of tissue repair and remodelling following injury. As reports on these molecules in multiple sclerosis (MS) lesion with different lesional activity are rare, we studied the cellular localization of TGF-beta1, -beta2, and -beta3 isoforms, and TGF-beta receptor type I (TGF-betaR-I) and TGF-betaR-II expression by immunohistochemistry on postmortem brain tissue from MS and normal control cases. To validate the TGF-beta staining results we demonstrated that cultured human adult astrocytes that produce biological active TGF-beta2, and to a lesser extent TGF-beta1, were immunoreactive for all 3 TGF-beta isoforms. Moreover, at mRNA level TGF-beta1 was detected in MS and normal control brain tissue. In normal control brain tissue, TGF-beta isoforms were expressed in ramified microglia and TGF-beta2, and -beta3 on neuronal cells in the gray matter TGF-betaR-I and TGF-betaR-II expression was found on endothelial cells, astrocytes, microglia, and neurons. In active demyelinating MS lesions a strong to intense immunoreactivity was detected for all 3 TGF-beta isoforms in perivascular and parenchymal (foamy) macrophages and in hypertrophic astrocytes. Strong immunoreactivity for TGF-betaR-I and TGF-betaR-II was found on macrophages in both parenchymal and perivascular areas and on hypertrophic astrocytes and endothelial cells in active demyelinating MS lesions. In chronic active and inactive MS lesions, all 3 TGF-beta isoforms and their receptors were strongly expressed in hypertrophic astrocytes. Our findings strongly suggest that the expression of the various TGF-beta isoforms and their receptor types found in MS lesions with different cellular activity participate in reactive processes leading to the formation of chronic MS lesions.     

Microglial colonization of the developing mouse brain: the effect of CD11b deletion

Introduction: Microglia are resident mononuclear phagocytes of the central nervous system, which colonize the brain both prenatally and after birth. It is proposed that they enter the brain initially via the surrounding mesenchyme, via ventricles and later through blood vessels, but the mechanisms of entry and signals used for migration are still to be established. Previous studies have shown that ligands for some integrin adhesion molecules expressed on blood vessels in the developing nervous system (particularly ICAM‐1 and ICAM‐2 which bind CD11a/LFA‐1 and CD11b/Mac‐1), may act as potential recruiting signals for microglial precursors. This study addressed whether CD11b is influential on the migration of microglial precursors into the developing CNS. Material and methods: Ricinus communis agglutinin‐1 (RCA‐1) lectin histochemistry was employed to anatomically map the distribution of amoeboid and ramified microglia from embryonic day 15 (E15) to birth. Embryonic mouse brains from CD11b knockout (?/?) (n = 42), and heterozygote (+/?) (n = 52) mice generated on a C57/BL6 background (Melo et al. Cell Immunol 2000; 205 : 13–23) and wild‐type (+/+) (n = 37) litter mates were fixed in Bouin's solution, processed to paraffin wax and serially sectioned at 15–40 µm. To investigate further potential signals for recruiting microglial precursors, brains were immunochemically screened for integrins CD11a, CD11b, CD18, αX, VLA‐4 and the chemokine MCP‐1. Results: Microscopic analysis revealed the morphological transition of microglia from predominantly amoeboid forms at E15–E16 to a flourishing population of ramified cells at E19–E20. RCA‐1 histochemistry showed no clear differences in microglial distribution or timing of colonization between CD11b (?/?) and wild‐type mice from E15 to birth. Although CD11b deletion did not influence the timing of microglial ramification, there appeared to be fewer ramified cells in (?/?) mice within comparative brain regions. This requires further quantitative morphometric analysis. Of the integrins investigated, none were restricted to microglia and only VLA‐4 and αX showed reactivity within the CNS. However, MCP‐1 was notably localized to the cortical plate within all genotypes, consistent with previous findings in human foetal CNS (Rezaie & Male. Microsc Res Tech 1999; 45: 359–382). Conclusion: The results suggest that CD11b has little influence on the timing or regional distribution of microglia in the developing murine CNS. It is more likely that CD11b is only one of several factors that influence the migration and differentiation of these cells.     

Endothelial cell class II major histocompatibility complex molecule expression in stereotactic brain biopsies of patients with acute inflammatory/demyelinating conditions

To determine if central nervous system (CNS) microvessel endothelial cells express class II major histocompatibility complex (MHC) molecules in early demyelinating lesions in humans, cerebral white matter (WM) biopsies from patients with acute inflammatory/demyelinating conditions, including 4 with multiple sclerosis (MS), were immunostained for class II MHC and other antigens. Eight of 9 biopsies showed focal MHC class II-positive endothelial cells; there were none in the CNS of 1 of the MS patients at autopsy. There were more vessels with class II-positive endothelial cells in areas with intact WM and gliosis than in areas with active demyelination or control WM; class II-positive endothelial cells in small venules and capillaries were adjacent to transmigrating and perivascular CD4-positive cells. By immunoelectron microscopy, class II molecules were localized to vesicles in endothelial cell cytoplasm, suggesting the potential for antigen processing. Perivascular cells, parenchymal microglia, mononuclear cells and the perinuclear cytoplasm but not the processes of astrocytes were also class II-positive. These data indicate that in acute CNS inflammatory/demyelinating lesions, endothelial cells focally and apparently transiently express class II MHC molecules. This expression implies potential antigen-specific interactions, immunoregulatory or signalling functions in endothelial cells, or it may render them susceptible to CD4-positive cell-mediated cytotoxicity. Thus, class II-positive endothelial cells may have pivotal immunologic roles in initial stages of T cell responses in human CNS WM, particularly in acute MS lesions.     

小鼠局灶性脑缺血模型中细胞间粘附分子-1表达升高

目的　白细胞可以导致缺血细胞损伤,内皮细胞上表达的细胞间粘附分子－１（ＩＣＡＭ－１）有利于白细胞迁移至组织。本研究目的是对小鼠大脑中动脉栓塞（ＭＣＡＯ）后脑内ＩＣＡＭ－１ 蛋白在组织中表达和含量进行检测。方法　通过对成年雄性ＣＤ－１ 小鼠使用血管腔内尼龙线栓塞术,造成０、３、６、１２、２４、４８ 和７２ ｈ 的持续性大脑中动脉栓塞。缺血程度由激光多普勒流量仪确定,缺血脑组织ＩＣＡＭ－１ 的阳性表达由免疫组化技术检测,并用免疫沉淀和Ｗｅｓｔｅｒｎ 印迹来定量。结果　在大脑中动脉栓塞后,小鼠缺血脑半球的表面脑血流量减少到基准值的９％ ～１５％ 。各组间大脑中动脉栓塞过程中的脑血流量无显著差异。免疫组化技术显示,缺血中心区和末影区都见ＩＣＡＭ－１ 阳性的微血管内皮细胞,从缺血中心到缺血边缘区微血管内皮细胞表达ＩＣＡＭ－１ 出现增高的趋势。免疫沉淀和Ｗｅｓｔｅｒｎ 印迹分析结果表明,缺血区ＩＣＡＭ－１的表达在大脑中动脉栓塞后３ ｈ 增高,６～１２ ｈ 达到高峰,并持续到７２ ｈ。结论　研究表明,在持续性大脑中动脉栓塞的小鼠中检测到ＩＣＡＭ－１ 表达明显升高,因为在持续局灶性大脑中动脉缺血后ＩＣＡＭ－１ 可介导白细胞和内皮细胞粘附,加速     

A role for alpha4-integrin in the pathology following Semliki Forest virus infection

Migration of cells into the central nervous system (CNS) is a pivotal step in the pathogenesis of immune-mediated diseases such as multiple sclerosis (MS), experimental allergic encephalomyelitis (EAE) and virus-induced demyelinating diseases. Such migration is dependent on expression of adhesion molecules. The expression of adhesion molecules in the CNS was studied in Biozzi ABH mice infected with Semliki Forest virus (SFV) A7(74) - an important demyelinating model of MS. Expression of LFA-1alpha/CD11a, LFA-1beta/CD18 and ICAM-1/CD56 were rapidly elevated and remained high whereas MAC-1, CD44 and VCAM-1/CD106 were less widely expressed. The alpha4-integrin VLA-4/CD49d was more specifically associated with CNS lesions. To identify the importance of VLA-4, CD44, ICAM-1 and MAC-1 in the pathogenesis of SFV infection, monoclonal antibodies that block these adhesion molecules were administered in vivo during infection. Anti-VLA-4 treatment dramatically reduced the cellular infiltrates and demyelination within the CNS but did not affect the clearance of virus while antibodies to CD44, ICAM and MAC-1 antibody treatment had no effect. This study demonstrates that SFV infection induces the expression of adhesion molecules within the CNS and that VLA-4 plays an important role in the development of inflammation and demyelination in the CNS following SFV infection.     

Different expression of adhesion molecules on stromal cells and endothelial cells of capillary hemangioblastoma

Cell-cell and cell-matrix interactions are essential for many basic functions, including differentiation and development. In pathological conditions such as inflammation and tumorigenesis adhesive events also play a major role. Cellular adhesion is mediated by specific molecules expressed by both normal and neoplastic tissues. Capillary hemangioblastoma is a tumor of controversial origin, characterized by two major components, vacuolated stromal cells and a capillary network. In order to shed light on the differentiation of the stromal cells and the interactions between the two major components of hemangioblastoma we studied the expression of several adhesion molecules by immunocytochemistry. The endothelium-associated adhesion molecules (ICAM-1, ICAM-2, VCAM-1, PECAM-1 and ELAM-1) were expressed by endothelial cells within the tumors, but not by stromal cells. In contrast, the stromal cells showed strong neuronal cell adhesion molecule (NCAM/CD56) expression, further distinguishing them from endothelial cells. In addition, the stromal cells expressed CD44, which is of interest, as this membrane protein is linked to ezrin, a cytoskeleton-associated protein also expressed by stromal cells. We conclude that the stromal cells and endothelial cells of capillary hemangioblastoma exhibit quite divergent expression patterns of adhesion molecules. The NCAM expression in stromal cells suggests neuroectodermal or mesenchymal differentiation of this tumor. In addition, the NCAM expression could contribute to the sometimes problematic differential diagnosis between capillary hemangioblastoma and metastatic renal cell carcinoma of the central nervous system. Received: 17 December 1995 / Revised, accepted: 13 May 1996     

CD44s、CD44v6在颅内转移瘤与胶质母细胞瘤中的表达研究

目的:探讨粘附分子CD44基因蛋白在颅内转移瘤及胶质母细胞瘤中的表达及其与这些肿瘤侵袭、转移之间的关系。方法:应用标准型CD44(CD44s)和变异型CD44v6基因蛋白单克隆抗体,微波-LSAB免疫组化染色检测20例正常脑组织、35例脑胶质母细胞瘤和30例颅内转移瘤中CD44基因蛋白的表达情况。结果:20例正常脑组织中CD44s和CD44v6表达均为阴性:35例脑胶质母细胞瘤CD44s阳性表达率为100％(35／35),CD44v6表达为阴性:30例颅内转移瘤中CD44s阳性表达率为86.7％(26／30),CD44v6阳性表达率为66.7％(20／30)。CD44v6在颅内转移瘤及脑胶质母细胞瘤的表达差异有显著性(P<0.01)。结论:脑胶质母细胞瘤中CD44S的表达可能与其脑内侵袭过程有关,无CD44v6表达可能与其很少发生颅外转移有关,并有可能成为颅内转移瘤诊治的有用指标之一。     

The characterization of Ia expression during Sindbis virus encephalitis in normal and athymic nude mice

To characterize the expression of Ia systemically and locally on mononuclear cells during acute viral encephalitis, weanling mice were inoculated intracerebrally with Sindbis virus (SV), an alphavirus. Peripheral blood mononuclear cells, splenocytes and perivascular inflammatory cells in frozen brain sections were examined immunocytochemically for the presence of Ia. Ia expression increased in the spleen, blood and brain during SV encephalitis. The majority of the cells in the central nervous system (CNS) expressing Ia were perivascular mononuclear cells but Ia was also found on stellate parenchymal cells. Using one micrometer cryopreserved serial sections we identified these parenchymal cells as macrophages and microglia but not astrocytes. We also identified rare Ia-positive cells resembling endothelial cells. Frozen brain sections of SV-infected T cell-deficient nu/nu mice were also examined for Ia expression. The number and percentage of Ia-positive cells in perivascular inflammatory cells were markedly decreased compared to normal mice and Ia-positive stellate parenchymal cells were less numerous. This suggests that immunocompetent T cells are necessary for "normal" infiltration of inflammatory cells and for Ia expression in the CNS during SV encephalitis.     

CD40 expressed by human brain endothelial cells regulates CD4+ T cell adhesion to endothelium

Recent evidence suggests that interactions between CD40 on antigen presenting cells (APC) and CD40L on T cells generate signals that result in the activation of APC. In this study, the expression and function of CD40 was investigated in primary cultures of human brain microvessel endothelial cells (HBMEC). Results revealed constitutive expression of CD40 on untreated HBMEC. Stimulation with TNF-alpha, IFN-gamma, LPS or combination of TNF-alpha and IFN-gamma significantly upregulated CD40. The majority of CD40 molecules were localized on the apical surface of EC. Incubation of HBMEC with soluble CD40L resulted in increased expression of the adhesion molecules E-selectin, VCAM-1 and ICAM-1. Consequently, the adhesion of both resting and anti-CD3 activated CD4+ T lymphocytes to CD40L treated HBMEC was significantly increased compared to unstimulated EC. The expression of CD40 by cerebral endothelium, and endothelial cell activation following binding of CD40 to its ligand, CD40L, suggest a potential mechanism by which activated CD40L expressing T cells could enhance adhesion and migration of inflammatory cells across the blood-brain barrier (BBB) to sites of inflammation in the human central nervous system (CNS).     

缺氧复氧对血管内皮细胞ICAM-1表达及内皮-白细胞粘附的影响

目的：评价缺氧／复氧后血管内皮细胞ＩＣＡＭ－１表达及内皮－白细胞粘附率的变化。方法：体外培养大鼠骨髓血窦内皮细胞,缺氧９０ｍｉｎ,分别给予复氧１ｈ,２ｈ,４ｈ,８ｈ,１２ｈ,２４ｈ,用半定量ＥＬＩＳＡ法测ＩＣＡＭ－１的表达量,同时人皮细胞对中性粒细胞的粘附率。     

Expression and distribution of id helix-loop-helix proteins in human astrocytic tumors

The Id family of helix-loop-helix proteins is involved in a variety of processes, such as development, proliferation, and angiogenesis. In this study, we investigated the expression pattern of Id1, Id2, and Id3 in surgical specimens of human glial tumors. Western blot analysis demonstrated that all three Id proteins were expressed in astrocytic tumors. Expression levels in high-grade tumors were higher than in low-grade tumors. Immunohistochemical analysis confirmed that many of the tumor astrocytes exhibited strong Id1-3 IR. In contrast, in adult human normal brain, Id expression was low both in resting astrocytes and in endothelial cells. In tumor cells, Id proteins displayed cytoplasmic as well as nuclear localization. Id1-3 IR scores in tumor cells were positively correlated with proliferation indices. Moreover, Id1-3 IR was detected in endothelial cells of the astrocytic tumor blood vessels. The vascular Id1-3 expression correlated positively with tumor vascularity and grade. These results support the role of the Id gene family in the enhanced proliferative potential of tumor astrocytes. The evidence also supports the involvement of the Id gene family in tumor angiogenesis, a process that critically influences the malignant behavior of glial tumors.     

sICAM-1 and TNF-alpha induce MIP-2 with distinct kinetics in astrocytes and brain microvascular endothelial cells

The dysfunction of the blood-brain barrier (BBB) occurring after traumatic brain injury (TBI) is mediated by intracerebral neutrophil accumulation, chemokine release (e.g., interleukin (IL)-8) and upregulation of adhesion molecules (e.g., intercellular adhesion molecule (ICAM)-1). In patients with severe TBI, we previously found that elevated cerebrospinal fluid (CSF) IL-8 and soluble (s)ICAM-1 correlate with BBB dysfunction, and this prompted us to concomitantly monitor IL-8, sICAM-1 and their stimulator tumor necrosis factor (TNF)-alpha in CSF. Potential mechanisms for upregulation of the IL-8 analogue, murine macrophage inflammatory protein (MIP)-2, and sICAM-1 at the BBB were studied using cultured mouse astrocytes and brain microvascular endothelial cells (MVEC). In CSF of seven patients, IL-8 and sICAM-1 were elevated for 19 days after severe TBI, whereas TNF-alpha exceeded normal values on 9 days. Stimulation of MVEC and astrocytes with TNF-alpha simultaneously induced the release of MIP-2 reaching saturation by 4-8 hr and of sICAM-1 increasing continuously from 2-4 hr to 12 hr. Augmented sICAM-1 production correlated with enhanced membrane-bound (m)ICAM-1 expression in both cell types (r(s) = 0.96 and 0.90, P < 0.0001), but was markedly higher in astrocytes. The release of sICAM-1 was not influenced by IL-8 or MIP-2, although astrocytes and MVEC expressed the IL-8/MIP-2 receptor (CXCR-2) as determined by FACS analysis. Instead, we found that sICAM-1 strongly induced MIP-2 secretion by both cell types with kinetics differing from those evoked by TNF-alpha. If added together, sICAM-1 and TNF-alpha synergistically induced MIP-2 production suggesting the involvement of two different pathways for MIP-2 regulation.