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  • Lithium regulates hippocampal neurogenesis by ERK pathway and facilitates recovery of spatial learning and memory in rats after transient global cerebral ischemia. 17686496

    Recent studies have demonstrated that lithium has a neuroprotective effect against brain ischemia. Whether this effect is mediated by hippocampal neurogenesis remains unknown. The ERK (extracellular signal-regulated kinase) pathway plays an essential role in regulating neurogenesis. The present study was undertaken to investigate whether lithium regulates hippocampal neurogenesis by the ERK pathway and improves spatial learning and memory deficits in rats after ischemia. Rats were daily injected with lithium (1 mmol/kg) and 2 weeks later subjected to 15-min ischemia induced by four-vessel occlusion method. 5-bromo-2'-deoxyuridine (Brdu; 50mg/kg) was administrated twice daily at postischemic day 6, or for 3 days from postischemic day 6 to 8. We found that lithium increased the ERK1/2 activation after ischemia by western blotting analysis. There was a significant increase in Brdu-positive cells in the hippocampal dentate gyrus after lithium treatment, compared with ischemia group at postischemic days 7 and 21; furthermore, the survival rate of Brdu-positive cells was elevated by lithium. Inhibition of the ERK1/2 activation by U0126 diminished these effects of lithium. The percentages of Brdu-positive cells that expressed a neuronal marker or an astrocytic marker were not significantly influenced by lithium. Moreover, lithium improved the impaired spatial learning and memory ability in Morris water maze, and U0126 attenuated the behavioral improvement by lithium. These results suggest that lithium up-regulates the generation and survival of new-born cells in the hippocampus by the ERK pathway and improves the behavioral disorder in rats after transient global cerebral ischemia.
    Document Type:
    Reference
    Product Catalog Number:
    MAB377B
    Product Catalog Name:
    Anti-NeuN Antibody, clone A60, biotin conjugated
  • The PIDDosome mediates delayed death of hippocampal CA1 neurons after transient global cerebral ischemia in rats. 18845684

    A brief period of global brain ischemia, such as that induced by cardiac arrest or cardiopulmonary bypass surgery, causes cell death in vulnerable hippocampal CA1 pyramidal neurons days after reperfusion. Although numerous factors have been suggested to account for this phenomenon, the mechanisms underlying it are poorly understood. We describe a cell death signal called the PIDDosome, a protein complex of p53-induced protein with a death domain (PIDD), receptor-interacting protein-associated ICH-1/CED-3 homologous protein with a death domain (RAIDD), and procaspase-2. We induced 5 min of transient global cerebral ischemia (tGCI) using bilateral common carotid artery occlusion with hypotension. Western blot analysis showed that expression of twice-cleaved fragment of PIDD (PIDD-CC) increased in the cytosolic fraction of the hippocampal CA1 subregion and preceded procaspase-2 activation after tGCI. Caspase-2 cleaved Bid in brain homogenates. Co-immunoprecipitation and immunofluorescent studies demonstrated that PIDD-CC, RAIDD, and procaspase-2 were co-localized and bound directly, which indicates the formation of the PIDD death domain complex. Furthermore, we tested inhibition of PIDD expression by using small interfering RNA (siRNA) treatment that was initiated 48 h before tGCI. Administration of siRNA against PIDD decreased not only expression of PIDD-CC, but also activation of procaspase-2 and Bid, resulting in a decrease in histological neuronal damage and DNA fragmentation in the hippocampal CA1 subregion after tGCI. These results imply that PIDD plays an important role in procaspase-2 activation and delayed CA1 neuronal death after tGCI. We propose that PIDD is a hypothetical molecular target for therapy against neuronal death after tGCI.
    Document Type:
    Reference
    Product Catalog Number:
    CC127
    Product Catalog Name:
    Caspase 2, recombinant human active
  • NADPH oxidase mediates striatal neuronal injury after transient global cerebral ischemia. 20859296

    Medium spiny neurons (MSNs) constitute most of the striatal neurons and are known to be vulnerable to ischemia; however, the mechanisms of the vulnerability remain unclear. Activated forms of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase (NOX), which require interaction between cytosolic and membrane-bound subunits, are among the major sources of superoxide in the central nervous system. Although increasing evidence suggests that NOX has important roles in neurodegenerative diseases, its roles in MSN injury after transient global cerebral ischemia (tGCI) have not been elucidated. To clarify this issue, C57BL/6 mice were subjected to tGCI by bilateral common carotid artery occlusion for 22 minutes. Western blot analysis revealed upregulation of NOX subunits and recruitment of cytosolic subunits to the cell membrane at early (3 to 6 hours) and late (72 hours) phases after tGCI. Taken together with immunofluorescent studies, this activation arose in MSNs and endothelial cells at the early phase, and in reactive microglia at the late phase. Pharmacological and genetic inhibition of NOX attenuated oxidative injury, microglial activation, and MSN death after tGCI. These findings suggest that NOX has pivotal roles in MSN injury after tGCI and could be a therapeutic target for brain ischemia.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Potential role of PUMA in delayed death of hippocampal CA1 neurons after transient global cerebral ischemia. 19095966

    p53-upregulated modulator of apoptosis (PUMA), a BH3-only member of the Bcl-2 protein family, is required for p53-dependent and -independent forms of apoptosis. PUMA localizes to mitochondria and interacts with antiapoptotic Bcl-2 and Bcl-X(L) or proapoptotic Bax in response to death stimuli. Although studies have shown that PUMA is associated with pathomechanisms of cerebral ischemia, clearly defined roles for PUMA in ischemic neuronal death remain unclear. The purpose of this study was to determine potential roles for PUMA in cerebral ischemia.Five minutes of transient global cerebral ischemia (tGCI) were induced by bilateral common carotid artery occlusion combined with hypotension.PUMA was upregulated in vulnerable hippocampal CA1 neurons after tGCI as shown by immunohistochemistry. In Western blot and coimmunoprecipitation analyses, PUMA localized to mitochondria and was bound to Bcl-X(L) and Bax in the hippocampal CA1 subregion after tGCI. PUMA upregulation was inhibited by pifithrin-alpha, a specific inhibitor of p53, suggesting that PUMA is partly controlled by the p53 transcriptional pathway after tGCI. Furthermore, reduction in oxidative stress by overexpression of copper/zinc superoxide dismutase, which is known to be protective of vulnerable ischemic hippocampal neurons, inhibited PUMA upregulation and subsequent hippocampal CA1 neuronal death after tGCI.These results imply a potential role for PUMA in delayed CA1 neuronal death after tGCI and that it could be a molecular target for therapy.
    Document Type:
    Reference
    Product Catalog Number:
    MAB377
    Product Catalog Name:
    Anti-NeuN Antibody, clone A60
  • Mitochondrial translocation of p53 mediates release of cytochrome c and hippocampal CA1 neuronal death after transient global cerebral ischemia in rats. 16870742

    Although p53 is a key modulator of cellular stress responses, the mechanism of p53-mediated apoptosis is ambiguous. p53 can mediate apoptosis in response to death stimuli by transcriptional activation of proapoptotic genes and transcriptional-independent mechanisms. Recent studies have shown that the p53 protein can directly induce permeabilization of the outer mitochondrial membrane by forming a inhibitory complex with a protective Bcl-2 family protein, resulting in cytochrome c release. However, how the mitochondrial p53 pathway mediates neuronal apoptosis after cerebral ischemia remains unclear. We examined the interaction between the mitochondrial p53 pathway and vulnerable hippocampal CA1 neurons in rats using a transient global cerebral ischemia (tGCI) model. Western blot analysis and immunofluorescent staining revealed mitochondrial p53 translocation after tGCI in the hippocampal CA1 neurons. Coimmunoprecipitation revealed that translocated p53 bound to Bcl-X(L) in the mitochondrial fraction. To examine the effect of a specific p53 inhibitor on the mitochondrial p53 pathway and apoptotic cell death after tGCI, we intravenously administered pifithrin-alpha (PFT). Mitochondrial p53 translocation and interaction between p53 and Bcl-X(L) were prevented by treatment with PFT. Moreover, cytochrome c release from mitochondria and subsequent apoptotic CA1 neuronal death were decreased with PFT treatment. These results suggest that the mitochondrial p53 pathway is one of the novel mechanisms mediating delayed death of vulnerable hippocampal CA1 neurons after tGCI.
    Document Type:
    Reference
    Product Catalog Number:
    MAB377X
    Product Catalog Name:
    Anti-NeuN Antibody, clone A60, Alexa Fluor®488 conjugated
  • Consistent injury to medium spiny neurons and white matter in the mouse striatum after prolonged transient global cerebral ischemia. 21309724

    A reproducible transient global cerebral ischemia (tGCI) mouse model has not been fully established. Although striatal neurons and white matter are recognized to be vulnerable to ischemia, their injury after tGCI in mice has not been elucidated. The purpose of this study was to evaluate injuries to striatal neurons and white matter after tGCI in C57BL/6 mice, and to develop a reproducible tGCI model. Male C57BL/6 mice were subjected to tGCI by bilateral common carotid artery occlusion (BCCAO). Mice whose cortical cerebral blood flow after BCCAO decreased to less than 13% of the pre-ischemic value were used. Histological analysis showed that at 3 days after 22 min of BCCAO, striatal neurons were injured more consistently than those in other brain regions. Quantitative analysis of cytochrome c release into the cytosol and DNA fragmentation in the striatum showed consistent injury to the striatum. Immunohistochemistry and Western blot analysis revealed that DARPP-32-positive medium spiny neurons, the majority of striatal neurons, were the most vulnerable among the striatal neuronal subpopulations. The striatum (especially medium spiny neurons) was susceptible to oxidative stress after tGCI, which is probably one of the mechanisms of vulnerability. SMI-32 immunostaining showed that white matter in the striatum was also consistently injured 3 days after 22 min of BCCAO. We thus suggest that this is a tGCI model using C57BL/6 mice that consistently produces neuronal and white matter injury in the striatum by a simple technique. This model can be highly applicable for elucidating molecular mechanisms in the brain after global ischemia.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • A membrane-bound trehalase from Chironomus riparius larvae: purification and sensitivity to inhibition. 20542873

    A preparation of a membrane-bound trehalase from the larvae of the midge Chironomus riparius (Diptera: Chironomidae) was obtained by detergent solubilization, ion-exchange chromatography and concanavalin A affinity chromatography. Trehalase was purified 1080-fold to a specific activity of 75 U mg(-)(1). The initial rate of trehalase activity followed Henri-Michaelis-Menten kinetics with a K(m) of 0.48 +/- 0.04 mM. Catalytic efficiency was maximal at pH 6.5. The activity was highly inhibited by mono- and bicyclic iminosugar alkaloids such as (in order of potency) casuarine (IC(50) = 0.25 +/- 0.03 microM), deoxynojirimycin (IC(50) = 2.83 +/- 0.34 microM) and castanospermine (IC(50) = 12.7 +/- 1.4 microM). Increasing substrate concentration reduced the inhibition. However, in the presence of deoxynojirimycin, Lineweaver-Burk plots were curvilinear upward. Linear plots were obtained with porcine trehalase. Here, we propose that deoxynojirimycin inhibits the activity of trehalase from C. riparius according to a ligand exclusion model. Inhibition was further characterized by measuring enzyme activity in the presence of a series of casuarine and deoxynojirimycin derivatives. For comparison, inhibition studies were also performed with porcine trehalase. Results indicate substantial differences between midge trehalase and mammalian trehalase suggesting that, in principle, inhibitors against insect pests having trehalase as biochemical targets can be developed.
    Document Type:
    Reference
    Product Catalog Number:
    2752
    Product Catalog Name:
    BrdU Cell Proliferation Kit
  • Profiling markers of prognosis in colorectal cancer. 16489072

    Colorectal cancer is one of the most common forms of cancer in developed nations and the incidence of this disease is increasing. There is a need to further stratify prognostically distinct groups of colorectal cancer, and the purpose of this study was to identify prognostically significant immunohistochemical marker profiles in colorectal cancer.In this study, a range (n = 23) of markers [pRb, p16, p21, p27, p53, proliferating cell nuclear antigen, cyclin D1, bcl-2, epidermal growth factor receptor, C-erb-B2, topoisomerase-I, liver fatty acid-binding protein, matrix metalloproteinases (MMP) 1-3, 7, 9, and 13, MT1-MMP, MT2-MMP, and tissue inhibitors of MMP 1-3] of putative prognostic significance have been investigated by immunohistochemistry on formalin-fixed, wax-embedded sections in a series (n = 90) of stage III (Dukes C) colorectal cancers. An immunohistochemical score based on the intensity of immunoreactivity and, where relevant, the proportion of immunoreactive cells was established for each marker.Unsupervised two-dimensional hierarchical cluster analysis identified three distinct cluster groups (designated groups 1-3) with different marker profiles. There were significant survival differences between groups 1 and 2 (log rank = 11.48; P = 0.0007) and between groups 1 and 3 (log rank = 8.32; P = 0.0039). Multivariate analysis showed that the complete marker profile was independently the most significant prognostic factor (hazard ratio, 2.27; 95% confidence interval, 1.15-4.48; P = 0.004).This study has identified an immunohistochemical marker profile of colorectal cancer and showed that it is an independent indicator of prognosis in this type of cancer.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Lymphoid follicles are generated in high-grade cervical dysplasia and have differing characteristics depending on HIV status. 11786409

    The exact role of the mucosal immune response in the pathogenesis of human papillomavirus (HPV)-related premalignant and malignant diseases of the genital tract is poorly understood. We used immunohistochemical analysis to characterize immune cells in normal cervix (N = 21), HIV-negative high-grade dysplasia (N = 21), and HIV-positive high-grade dysplasia (N = 30). Classical germinal centers were present in 4.7% of normal cervix, 33% of high-grade lesions from HIV-negative women, and 3.3% of high-grade lesions from HIV-positive women (P = 0.003). HPV16 E7 antigen was detected in a subset of germinal centers, indicating that the secondary immune response was directed in part against HPV. Lymphoid follicles were present in 9.5% of normal cervix, 57% of HIV-negative high-grade dysplasia, and 50% of HIV-positive high-grade dysplasia (P = 0.001 normal versus high-grade). A novel type of lymphoid aggregate, consisting predominantly of CD8(+) T cells, was detected in 4.8% of normal cervix, 0% of HIV-negative high-grade dysplasia, and 40% of HIV-positive high-grade dysplasia (P < 0.001). The recurrence rate of high-grade dysplasia within one year was significantly higher in women with such CD8(+) T cell-dominant aggregates (P = 0.02). In summary, the types of lymphoid follicle in lesions from HIV-positive women were significantly different from those from HIV-negative women, and these differences are associated with the worse clinical outcome in HIV-positive women.
    Document Type:
    Reference
    Product Catalog Number:
    MAB874
    Product Catalog Name:
    Anti-Papillomavirus Antibody, 16, 18 E6 protein, clone C1P5