A Humanin Derivative Reduces Amyloid Beta Accumulation and Ameliorates Memory Deficit in Triple Transgenic Mice

Humanin (HN), a 24-residue peptide, was identified as a novel neuroprotective factor and shows anti-cell death activity against a wide spectrum of Alzheimer\u27s disease (AD)-related cytotoxicities, including exposure to amyloid beta (Abeta), in vitro. We previously demonstrated that the injection of S14G-HN, a highly potent HN derivative, into brain ameliorated memory loss in an Abeta-injection mouse model. To fully understand HN\u27s functions under AD-associated pathological conditions, we examined the effect of S14G-HN on triple transgenic mice harboring APPswe, tauP310L, and PS-1M146V that show the age-dependent development of multiple pathologies relating to AD. After 3 months of intranasal treatment, behavioral analyses showed that S14G-HN ameliorated cognitive impairment in male mice. Moreover, ELISA and immunohistochemical analyses showed that Abeta levels in brains were markedly lower in S14G-HN-treated male and female mice than in vehicle control mice. We also found the expression level of neprilysin, an Abeta degrading enzyme, in the outer molecular layer of hippocampal formation was increased in S14G-HN-treated mouse brains. NEP activity was also elevated by S14G-HN treatment in vitro. These findings suggest that decreased Abeta level in these mice is at least partly attributed to S14G-HN-induced increase of neprilysin level. Although HN was identified as an anti-neuronal death factor, these results indicate that HN may also have a therapeutic effect on amyloid accumulation in AD

In Vivo Turnover of Tau and APP Metabolites in the Brains of Wild-Type and Tg2576 Mice: Greater Stability of sAPP in the β-Amyloid Depositing Mice

The metabolism of the amyloid precursor protein (APP) and tau are central to the pathobiology of Alzheimer's disease (AD). We have examined the in vivo turnover of APP, secreted APP (sAPP), Aβ and tau in the wild-type and Tg2576 mouse brain using cycloheximide to block protein synthesis. In spite of overexpression of APP in the Tg2576 mouse, APP is rapidly degraded, similar to the rapid turnover of the endogenous protein in the wild-type mouse. sAPP is cleared from the brain more slowly, particularly in the Tg2576 model where the half-life of both the endogenous murine and transgene-derived human sAPP is nearly doubled compared to wild-type mice. The important Aβ degrading enzymes neprilysin and IDE were found to be highly stable in the brain, and soluble Aβ40 and Aβ42 levels in both wild-type and Tg2576 mice rapidly declined following the depletion of APP. The cytoskeletal-associated protein tau was found to be highly stable in both wild-type and Tg2576 mice. Our findings unexpectedly show that of these various AD-relevant protein metabolites, sAPP turnover in the brain is the most different when comparing a wild-type mouse and a β-amyloid depositing, APP overexpressing transgenic model. Given the neurotrophic roles attributed to sAPP, the enhanced stability of sAPP in the β-amyloid depositing Tg2576 mice may represent a neuroprotective response

Therapeutic versus neuroinflammatory effects of passive immunization is dependent on Abeta/amyloid burden in a transgenic mouse model of Alzheimer's disease

Abstract Background Passive immunization with antibodies directed to Aβ decreases brain Aβ/amyloid burden and preserves memory in transgenic mouse models of Alzheimer's disease (AD). This therapeutic strategy is under intense scrutiny in clinical studies, but its application is limited by neuroinflammatory side effects (autoimmune encephalitis and vasogenic edema). Methods We intravenously administered the monoclonal Aβ protofibril antibody PFA1 to aged (22 month) male and female 3 × tg AD mice with intermediate or advanced AD-like neuropathologies, respectively, and measured brain and serum Aβ and CNS cytokine levels. We also examined 17 month old 3 × tg AD female mice with intermediate pathology to determine the effect of amyloid burden on responses to passive immunization. Results The 22 month old male mice immunized with PFA1 had decreased brain Aβ, increased serum Aβ, and no change in CNS cytokine levels. In contrast, 22 month old immunized female mice revealed no change in brain Aβ, decreased serum Aβ, and increased CNS cytokine levels. Identical experiments in younger (17 month old) female 3 × tg AD mice with intermediate AD-like neuropathologies revealed a trend towards decreased brain Aβ and increased serum Aβ accompanied by a decrease in CNS MCP-1. Conclusions These data suggest that passive immunization with PFA1 in 3 × tg AD mice with intermediate disease burden, regardless of sex, is effective in mediating potentially therapeutic effects such as lowering brain Aβ. In contrast, passive immunization of mice with a more advanced amyloid burden may result in potentially adverse effects (encephalitis and vasogenic edema) mediated by certain proinflammatory cytokines.http://deepblue.lib.umich.edu/bitstream/2027.42/78261/1/1742-2094-7-57.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78261/2/1742-2094-7-57.pdfPeer Reviewe

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix

S14G-HN does not affect APP production and processing.

<p>Brain homogenate of 3xTg-AD mice treated with S14G-HN (HNG or H) or vehicle (veh or V) was subjected to immunoblot analysis using anti-APP C-terminus (<b>A</b>) or anti-sAPPalpha (<b>B</b>) (upper panels) and anti-beta-actin (lower panels) antibodies.</p

Brain Abeta level was sustained in S14G-HN-treated 3xTg-AD mice.

<p>After behavioral tests, mice were sacrificed at 17 months of age. Abeta was extracted from brain homogenates using formic acid. <b>A</b>. Amount of human Abeta40 was measured by ELISA and shown as mean±SEM. P values of Student t-test are shown. Number of animals were vehicle male = 7, female = 9, S14G-HN male = 9, female = 7. Lower level of Abeta was detected in S14G-HN treated mice (black columns). Statistical significance was observed in female but not male compared with vehicle treated mice (dark grey columns). Dotted line plots show Abeta40 levels of naïve 3xTg-AD mice at the indicated age <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016259#pone.0016259-HirataFukae1" target="_blank">[37]</a>. <b>B–G</b>. Immunohistochemical analysis of amyloid plaques. Brains were fixed with 4% paraformaldehyde and 30 µm sagittal sections were subjected to immunostaining using anti-Abeta antibody (82E1) and biotin-conjugated secondary antibody followed by visualization with ABC method. <b>B, D, F.</b> vehicle-treated female mice, <b>C, E, G.</b> S14G-HN-treated female mice. <b>F, G.</b> magnified view of subculum regions in C and E, respectively. Bar  = 500 µm in B-E,  = 100 µm in F, G.</p