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Brain Microvascular Endothelial Cells (brain + microvascular_endothelial_cell)
Kinds of Brain Microvascular Endothelial Cells Selected AbstractsBlood,brain barrier breakdown and repair by Src after thrombin-induced injuryANNALS OF NEUROLOGY, Issue 4 2010Da-Zhi Liu PhD Objective Thrombin mediates the life-threatening cerebral edema that occurs after intracerebral hemorrhage. Therefore, we examined the mechanisms of thrombin-induced injury to the blood,brain barrier (BBB) and subsequent mechanisms of BBB repair. Methods Intracerebroventricular injection of thrombin (20U) was used to model intraventricular hemorrhage in adult rats. Results Thrombin reduced brain microvascular endothelial cell (BMVEC) and perivascular astrocyte immunoreactivity,indicating either cell injury or death,and functionally disrupted the BBB as measured by increased water content and extravasation of sodium fluorescein and Evans blue dyes 24 hours later. Administration of nonspecific Src family kinase inhibitor (PP2) immediately after thrombin injections blocked brain edema and BBB disruption. At 7 to 14 days after thrombin injections, newborn endothelial cells and astrocytes were observed around cerebral vessels at the time when BBB permeability and cerebral water content resolved. Delayed administration of PP2 on days 2 through 6 after thrombin injections prevented resolution of the edema and abnormal BBB permeability. Interpretation Thrombin, via its protease-activated receptors, is postulated to activate Src kinase phosphorylation of molecules that acutely injure the BBB and produce edema. Thus, acute administration of Src antagonists blocks edema. In contrast, Src blockade for 2 to 6 days after thrombin injections is postulated to prevent resolution of edema and abnormal BBB permeability in part because Src kinase proto-oncogene members stimulate proliferation of newborn BMVECs and perivascular astrocytes in the neurovascular niche that repair the damaged BBB. Thus, Src kinases not only mediate acute BBB injury but also mediate chronic BBB repair after thrombin-induced injury. ANN NEUROL 2010;67:526,533 [source] Role of the aging vasculature and Erb B-2 signaling in epidermal growth factor-dependent intravasion of breast carcinoma cells,CANCER, Issue 1 2004Daniel J. Price Ph.D. Abstract BACKGROUND The risks for developing breast carcinoma and dying from the disease increase with age. Mortality from breast carcinoma usually is due to metastatic disease. Metastatic cells are able to invade into the vascular tissue in a growth factor-dependent manner. Because breast carcinoma mortality increases with age, examination of breast carcinoma interactions with young and aged endothelial cells is essential. METHODS We studied a series of breast epithelial cells (HMT-3522 cells) that exhibited either noninvasive characteristics (S-1 cells) or epidermal growth factor (EGF)-dependent invasive characteristics (T4-2 cells). RESULTS Increased invasion of HMT-3522 cells was observed across an aged rat brain microvascular endothelial cell (BMEC) monolayer that was isolated from aged rats (24 months) compared with young rats (age 1 month). This increased invasion was inhibited by the specific EGF receptor inhibitor, AG1478, and by the Erb B-2-specific inhibitor, AG825. To analyze further the contribution of Erb B-2 to the EGF-dependent invasion of HMT-3522 cells, T4-2 cells were treated with the Erb B-2-specific therapeutic antibody trastuzumab and with the specific inhibitor AG825 and were then assayed for invasion. Both inhibitors led to a significant decrease in EGF-dependent invasion. Erb B-2 expression was found to be elevated in T4-2 cells (, 5-fold higher) compared with S-1 cells. However, treatment of T4-2 cells with the specific Erb B-2 inhibitor, AG825, failed to inhibit EGF-mediated signaling to phosphatidylinositol 3-kinase or extracellular-regulated kinases 1 and 2. CONCLUSIONS The current study findings indicate that aging of endothelium may contribute to the invasive phenotype of breast carcinoma cells and that "cross-talk" between Erb B-2 and EGF receptor is required for the intravasion of these cells into the surrounding vasculature. Cancer 2004. © 2004 American Cancer Society. [source] Development of an in vitro blood,brain barrier model to study the effects of endosulfan on the permeability of tight junctions and a comparative study of the cytotoxic effects of endosulfan on rat and human glial and neuronal cell culturesENVIRONMENTAL TOXICOLOGY, Issue 3 2006Melissa P. L. Chan Abstract Endosulfan, an organochlorine (OC) insecticide that belongs to the cyclodiene group, is one of the most commonly used pesticides to control pests in vegetables, cotton, and fruits. Porcine brain microvascular endothelial cells were used to develop a model to study the effects of endosulfan on the permeability of tight junctions in the blood,brain barrier (BBB). BBB permeability, measured as transendothelial electrical resistance, decreased in a dose- and time-dependent manner when treated with ,-endosulfan, ,-endosulfan, or endosulfan sulfate. Cytotoxicity testing revealed that the three endosulfans did not cause cell death at concentrations of 10 ,M and below. The ratio of the average permeability of the filter-grown endothelial cell monolayer to 14C-endosulfan (Pe) going from the outer to the inner compartments with that going from the inner to the outer compartments was approximately 1:1.2,2.1 after exposure to concentrations of 0.01,10 ,M. ,-Endosulfan, ,-endosulfan, and endosulfan sulfate had cytotoxic effects on rat glial (C6) and neuronal (PC12) cell cultures as well as on human glial (CCF-STTG1) and neuronal (NT2) cell cultures. The effects of ,-endosulfan were highly selective, with a wide range of LC50 values found in the different cultures, ranging from 11.2 ,M for CCF-STTG1 cells to 48.0 ,M for PC12 cells. In contrast, selective neurotoxicity was not so manifest in glial and neuronal cell cultures after exposure to endosulfan sulfate, as LC50 values were in the range of 10.4,21.6 ,M. CCF-STTG1 cells were more sensitive to ,-endosulfan and endosulfan sulfate, whereas NT2 cells were more sensitive to ,-endosulfan. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 223,235, 2006. [source] Nitric Oxide-Induced Changes in Endothelial Expression of Phosphodiesterases 2, 3, and 5HEADACHE, Issue 3 2010Christoph J. Schankin MD (Headache 2010;50:431-441) Objective., To investigate nitric oxide (NO)-mediated changes in expression of cyclic nucleotide degrading phosphodiesterases 2A (PDE2A), PDE3B, and PDE5A in human endothelial cells. Background., Nitric oxide induces production of cyclic guanosine monophosphate (cGMP), which along with cyclic adenosine monophosphate (cAMP) is degraded by PDEs. NO donors and selective inhibitors of PDE3 and PDE5 induce migraine-like headache and play a role in endothelial dysfunction during stroke. The current study investigates possible NO modulation of cGMP-related PDEs relevant to headache induction in a cell line containing such PDEs. Methods., Real time polymerase chain reaction and Western blots were used to show expression of PDE2A, PDE3B, and PDE5A in a stable cell line of human brain microvascular endothelial cells. Effects of NO on PDE expression were analyzed at specific time intervals after continued DETA NONOate administration. Results., This study shows the expression of PDE2A, PDE3B, and PDE5A mRNA and PDE3B and PDE5A protein in human cerebral endothelial cells. Long-term DETA NONOate administration induced an immediate mRNA up-regulation of PDE5A (1.9-fold, 0.5 hour), an early peak of PDE2A (1.4-fold, 1 and 2 hours) and later up-regulation of both PDE3B (1.6-fold, 4 hours) and PDE2A (1.7-fold, 8 hours and 1.2-fold after 24 hours). Such changes were, however, not translated into significant changes in protein expression indicating few, if any, functional effects. Conclusions., Long-term NO stimulation modulated PDE3 and PDE5 mRNA expression in endothelial cells. However, PDE3 and PDE5 protein levels were unaffected by NO. The presence of PDE3 or PDE5 in endothelial cells indicates that selective inhibitors may have functional effects in such cells. A complex interaction of cGMP and cAMP in response to NO administration may take place if the mRNA translates into active protein. Whether or not this plays a role in the headache mechanisms remains to be investigated. [source] Glioma cells under hypoxic conditions block the brain microvascular endothelial cell death induced by serum starvationJOURNAL OF NEUROCHEMISTRY, Issue 1 2005Yoshifumi Ueda Abstract Angiogenesis is one of essential components for the growth of neoplasms, including malignant gliomas. However, tumor vascularization is often poorly organized and marginally functional due to tumor strucutural abnormalities, inducing regional or temporal hypoxic conditions and nutritional shortages in tumor tissues. We investigated how during angiogenesis migrating endothelial cells survive in these hypoxic and reduced nutritional conditions. Human brain microvascular endothelial cells (HBMECs) underwent apoptosis and necrosis after serum withdrawal. This endothelial cell death was blocked by recombinant VEGF protein or the culture medium of U251 glioma cells exposed to hypoxia (H-CM). Hypoxic treatment increased vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-,) expression in U251 glioma cells. H-CM activated nuclear factor-,B (NF,B) protein and increased the gene expression of antiapoptotic factors including Bcl-2, Bcl-XL, survivin and X-chromosome-linked inhibitor of apoptosis protein (XIAP) in endothelial cells. The survival activity of H-CM for endothelial cells was abolished by two kinds of VEGF inhibitors {Cyclopeptidic VEGF inhibitor and a VEGF receptor tyrosine kinase inhibitor (4-[(4,-chloro-2,-fluoro) phenylamino]-6, 7-dimethoxyquinazoline)} or NF,B inhibitors (ALLN and BAY 11,7082). These VEGF inhibitors did not block the activation of NF,B induced by H-CM in endothelial cells. On the contrary, TNF-, antagonist WP9QY enhanced the survival activity of H-CM for endothelial cells and blocked NF,B activation induced by H-CM under serum-starved conditions. Taken together, our data suggest that both the secretion of VEGF from glioma cells and activation of NF,B in endothelial cells induced by TNF-, are necessary for endothelial cell survival as they increase the expression of antiapoptotic genes in endothelial cells under conditions of serum starvation. These pathways may be one of the mechanisms by which angiogenesis is maintained in glioma tissues. [source] HIV-Tat protein induces oxidative and inflammatory pathways in brain endotheliumJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Michal Toborek Abstract Impaired function of the brain vasculature might contribute to the development of HIV-associated dementia. For example, injury or dysfunction of brain microvascular endothelial cells (BMEC) can lead to the breakdown of the blood,brain barrier (BBB) and thus allow accelerated entry of the HIV-1 virus into the CNS. Mechanisms of injury to BMEC during HIV-1 infection are not fully understood, but the viral gene product Tat may be, at least in part, responsible for this effect. Tat can be released from infected perivascular macrophages in the CNS of patients with AIDS, and thus BMEC can be directly exposed to high concentrations of this protein. To study oxidative and inflammatory mechanisms associated with Tat-induced toxicity, BMEC were exposed to increasing doses of Tat1,72, and markers of oxidative stress, as well as redox-responsive transcription factors such as nuclear factor-,B (NF-,B) and activator protein-1 (AP-1), were measured. Tat1,72 treatment markedly increased cellular oxidative stress, decreased levels of intracellular glutathione and activated DNA binding activity and transactivation of NF-,B and AP-1. To determine if Tat1,72 can stimulate inflammatory responses in brain endothelium in vivo, expression of monocyte chemoattractant protein-1 (MCP-1), an NF-,B and AP-1-dependent chemokine, was studied in brain tissue in mice injected with Tat1,72 into the right hippocampus. Tat1,72 markedly elevated the MCP-1 mRNA levels in brain tissue. In addition, a double immunohistochemistry study revealed that MCP-1 protein was markedly overexpressed on brain vascular endothelium. These data indicate that Tat1,72 can induce redox-related inflammatory responses both in in vitro and in vivo environments. These changes can directly lead to disruption of the BBB. Thus, Tat can play an important role in the development of detrimental vascular changes in the brains of HIV-infected patients. [source] Proapoptotic Nitric Oxide Production in Amyloid , Protein-Treated Cerebral Microvascular Endothelial CellsMICROCIRCULATION, Issue 2 2007CHIWAKA KIMURA ABSTRACT Objective: The objective of this study was to investigate the effects of amyloid , protein (A,) on cerebral microvascular endothelium, and their possible involvement in A,-induced apoptosis in the neighboring cells. Methods: Cultured bovine brain microvascular endothelial cells (BBECs) were incubated with A, for 24 h. Production of nitric oxide (NO) was assessed by nitric oxide-sensitive fluorescent dye, DAF-2, and the expression of NO synthase (NOS) proteins was examined by Western blotting. Effects of A,-treated microvascular endothelium on the DNA damage of the neighboring cells were assessed by single-cell gel electrophoresis. Results: A, increased the expression of iNOS protein, but did not affect eNOS and nNOS expressions in BBECs. A,-treated BBECs showed spontaneous NO production in the presence of L-arginine. The neural cell line PC12 showed marked apoptosis after being co-cultured with A,-treated BBECs for 48 h, and the apoptosis was as potent as that induced by the inflammatory stimuli lipopolysaccharide and interferon-,. The DNA damage of PC12 cells evoked by co-culture with A,-treated BBECs was prevented by L- NG -nitroarginine methyl ester, an inhibitor of NOS. Conclusions: These results indicate that A, induces the expression of iNOS in BBECs, and that microvascular endothelium-derived NO may induce apoptosis in neighboring neural cells. [source] Invasion of Cryptococcus neoformans into human brain microvascular endothelial cells requires protein kinase C-, activationCELLULAR MICROBIOLOGY, Issue 9 2008Ambrose Jong Summary Pathogenic fungus Cryptococcus neoformans has a predilection for the central nervous system causing devastating meningoencephalitis. Traversal of C. neoformans across the blood,brain barrier (BBB) is a crucial step in the pathogenesis of C. neoformans. Our previous studies have shown that the CPS1 gene is required for C. neoformans adherence to the surface protein CD44 of human brain microvascular endothelial cells (HBMEC), which constitute the BBB. In this report, we demonstrated that C. neoformans invasion of HBMEC was blocked in the presence of G109203X, a protein kinase C (PKC) inhibitor, and by overexpression of a dominant-negative form of PKC, in HBMEC. During C. neoformans infection, phosphorylation of PKC, was induced and the PKC enzymatic activity was detected in the HBMEC membrane fraction. Our results suggested that the PKC, isoform might play a crucial role during C. neoformans invasion. Immunofluorescence microscopic images showed that induced phospho-PKC, colocalized with ,-actin on the membrane of HBMEC. In addition, cytochalasin D (an F-filament-disrupting agent) inhibited fungus invasion into HBMEC in a dose-dependent manner. Furthermore, blockage of PKC, function attenuated actin filament activity during C. neoformans invasion. These results suggest a significant role of PKC, and downstream actin filament activity during the fungal invasion into HBMEC. [source] | |||||||||||||