Anti-Protein Kinase C-βII monoclonal antibody, clone O12-T

The hallmarks of sporadic Alzheimer's disease (AD) are extracellular amyloid deposits, intracellular neurofibrillary tangles (NFTs), and neuronal death. Hyperphosphorylation of tau is a key factor in the generation of NFTs. Mitogen activated protein kinase 1 (MAPK1) and protein kinase C beta (PRKCB) are thought to play a role in hyperphosphorylation, and PRCKB is thought to be involved in hypoxic stress and vascular dysfunction, and to trigger MAPK phosphorylation pathways. We performed single-cell analyses of neurons with different vulnerabilities to AD-related changes. Using quantitative PCR (qPCR), we measured the levels of MAPK1 and PRKCB transcript in CA1 (high vulnerability), CA2 pyramidal cells from the hippocampus, granule cells from the cerebellum (low vulnerability), and neurons from the brain stem (nucleus tractus spinalis nervi trigemini, characterized by early neurophysiological deficits) at progressive Braak stages compared to age-matched controls. The highly vulnerable CA1 pyramidal neurons were characterized by age-and disease-unrelated increases in PRCKB levels and by age-and disease-related increases in MAPK1 levels. In contrast, low PRKCB levels were found in CA2 pyramidal neurons, and MAPK1 levels were elevated in controls and intermediate AD stages. Both PRKCB and MAPK1 were increased in the late AD stages. MAPK1 and PRKCB levels were low in the brainstem and cerebellum. We propose that alterations in the expression of these two genes occur early in the pathogenesis of AD in a region-specific manner. In addition, multiple signal transduction pathways need to be affected to result in AD instead of physiological aging.

In this study the role of PI3K/Akt signaling pathway in arsenic trioxide (ATO)-treated parental Jurkat cells and also in derived ATO-resistant clones grown in the presence of given ATO concentration was investigated. ATO-resistant clones (cultured for 8-12 weeks in the presence of 1, 2.5 and 5 mu M ATO) were characterized by high viability in the presence of ATO but slower growth rate compared to the parental cells. Morphological and functional characterization of derived ATO-resistant clones revealed that they did not differ fundamentally from parental Jurkat cells in terms of cell size, level of GSH, the lysosomal fluorescence or CD95/Fas surface antigen expression. However, a slight increase in the mitochondrial potential (JC-1 staining) was detected in the clones compared to parental Jurkat cells. Side population analysis (Vybrant DyeCycle Violet (TM) staining) in ATO resistant clones did not indicate any enrichment withcancer stem cells. Akt1/2, AktV or wortmannin inhibitors decreased viability of ATO-resistant clones grown in the presence of ATO, with no effect on ATO-treated parental cells. Flow cytometry analysis showed that ATO decreased the level of p-Akt in ATO-treated parental cells, while the resistant clones exhibited higher levels of p-Akt immunostaining than parental Jurkat cells. Expression analysis of 84 genes involved in the PI3K/Akt pathway revealed that this pathway was predominantly active in ATO-resistant clones. c-JUN seems to play a key role in the induction of cell death in ATO-treated parental Jurkat cells, as dose-dependent strong up-regulation of JUN was specific for the ATO-treated parental Jurkat cells. On the other hand, changes in expression of cyclin D1 (CCND1), insulin receptor substrate 1 (IRS1) and protein kinase C isoforms (PRKCZ,PRKCB and PRKCA) may be responsible for the induction of resistance to ATO. The changes in expression of growth factor receptor-bound protein 10 (GRB10) observed in ATO-resistant clones suggest a possibility of induction of different mechanisms in development of resistance to ATO depending on the drug concentration and thus involvement of different signaling mediators. (C) 2013 Elsevier Ireland Ltd. All rights reserved.