PKCε-mediated ERK1/2 activation involved in radiation-induced cell death in NIH3T3 cells

AbstractProtein kinase C (PKC) isoforms play distinct roles in cellular functions. We have previously shown that ionizing radiation activates PKC isoforms (α, δ, ε, and ζ), however, isoform-specific sensitivities to radiation and its exact mechanisms in radiation mediated signal transduction are not fully understood. In this study, we showed that overexpression of PKC isoforms (α, δ, ε, and ζ) increased radiation-induced cell death in NIH3T3 cells and PKCε overexpression was predominantly responsible. In addition, PKCε overexpression increased ERK1/2 activation without altering other MAP-kinases such as p38 MAPK or JNK. Co-transfection of dominant negative PKCε (PKCε-KR) blocked both PKCε-mediated ERK1/2 activation and radiation-induced cell death, while catalytically active PKCε construction augmented these phenomena. When the PKCε overexpressed cells were pretreated with PD98059, MEK inhibitor, radiation-induced cell death was inhibited. Co-transfection of the cells with a mutant of ERK1 or -2 (ERK1-KR or ERK2-KR) also blocked these phenomena, and co-transfection with dominant negative Ras or Raf cDNA revealed that PKCε-mediated ERK1/2 activation was Ras–Raf-dependent. In conclusion, PKCε-mediated ERK1/2 activation was responsible for the radiation-induced cell death

Accelerating and Supersonic Density Fluctuations in Coronal Hole Plumes: Signature of Nascent Solar Winds

Slow magnetoacoustic waves in a static background provide a seismological tool to probe the solar atmosphere in the analytic frame. By analyzing the spatiotemporal variation of the electron number density of plume structure in coronal holes above the limb for a given temperature, we find that the density perturbations accelerate with supersonic speeds in the distance range from 1.02 to 1.23 solar radii. We interpret them as slow magnetoacoustic waves propagating at about the sound speed with accelerating subsonic flows. The average sonic height of the subsonic flows is calculated to be 1.27 solar radii. The mass flux of the subsonic flows is estimated to be 44.1$\%$ relative to the global solar wind. Hence, the subsonic flow is likely to be the nascent solar wind. In other words, the evolution of the nascent solar wind in plumes at the low corona is quantified for the first time from imaging observations. Based on the interpretation, propagating density perturbations present in plumes could be used as a seismological probe of the gradually accelerating solar wind.Comment: Accepted for publication in ApJL, 11 pages, 5 figure

2D solar wind speeds from 6 to 26 solar radii in solar cycle 24 by using Fourier filtering

Measurement of the solar wind speed near the Sun is important for understanding the acceleration mechanism of the solar wind. In this study, we determine 2D solar wind speeds from 6 to 26 solar radii by applying Fourier motion filters to \textit{SOHO}/LASCO C3 movies observed from 1999 to 2010. Our method successfully reproduces the original flow speeds in the artificially generated data as well as streamer blobs. We measure 2D solar wind speeds from 1-day to 1-year timescales and their variation in solar cycle 24. We find that the solar wind speeds at timescales longer than a month in the solar maximum period are relatively uniform in the azimuthal direction, while they are clearly bimodal in the minimum period, as expected from the \textit{Ulysses} observations and IPS reconstruction. The bimodal structure appears at around 2006, becomes most distinctive in 2009, and abruptly disappears in 2010. The radial evolution of the solar wind speeds resembles the Parker's solar wind solution.Comment: 7 pages, 5 figures; accepted by PR

Improved blastocyst development of single cow OPU-derived presumptive zygotes by group culture with agarose-embedded helper embryos

<p>Abstract</p> <p>Background</p> <p>The <it>in vitro </it>culture of presumed zygotes derived from single cow ovum pick-up (OPU) is important for the production of quality blastocysts maintaining pedigree. The aim of the present study was to evaluate the agar chip-embedded helper embryo coculture system for single cow OPU-derived zygotes by assessing embryo quality.</p> <p>Methods</p> <p>Cumulus oocyte complexes (COCs) were collected from Hanwoo cows with high genetic merit twice a week using the ultra-sound guided OPU technique and from slaughterhouse ovaries. The Hanwoo cow COCs and slaughterhouse ovaries were matured <it>in vitro</it>, fertilized <it>in vitro </it>with thawed Hanwoo sperm and cultured for 24 h. The presumed zygotes were subsequently placed in three different culture systems: (1) control OPU (controlOPU) with single cow OPU-derived presumed zygotes (2~8); (2) agar chip-embedded slaughterhouse helper embryo coculture (agarOPU) with ten presumed zygotes including all presumed zygotes from a cow (2~8) and the rest from agar chip-embedded slaughterhouse presumed zygotes (8~2); and (3) slaughterhouse <it>in vitro </it>embryo production (sIVP) with ten slaughterhouse ovary-derived presumed zygotes, each in 50 μL droplets. Day 8 blastocysts were assayed for apoptosis and gene expression using real time PCR.</p> <p>Results</p> <p>The coculture system promoted higher blastocyst development in OPU zygotes compared to control OPU zygotes cultured alone (35.2 vs. 13.9%; P < 0.01). Genes predicted to be involved in implantation failure and/or embryo resorption were down-regulated (P < 0.05) in control OPU zygotes (<it>CD9</it>, 0.4-fold; <it>AKRAB</it>1, 0.3-fold) and in cocultured zygotes (<it>CD9</it>, 0.3-fold; <it>AKRAB</it>1, 0.3-fold) compared to sIVP blastocysts (1.0-fold). Moreover, genes involved in implantation and/or normal calf delivery were up-regulated (P < 0.05 to P < 0.01) in control OPU zygotes (<it>PGSH</it>2, 5.0-fold; <it>TXN</it>, 4.3-fold; <it>PLAU</it>, 1.7-fold) and cocultured zygotes (<it>PGSH</it>2, 14.5-fold; <it>TXN</it>, 3.2-fold; <it>PLAU</it>, 6.8-fold) compared to sIVP (1.0-fold) blastocysts. However, the expression of <it>PLAC8, TGF-β1, ODC1</it>, <it>ATP5A1 </it>and <it>CASP3 </it>did not differ between the three culture groups.</p> <p>Conclusions</p> <p>Results show that the agar chip-embedded helper embryo coculture system enhances developmental competence and embryo quality in cultures of limited numbers of high pedigree single cow OPU presumed zygotes.</p

Maysin and Its Flavonoid Derivative from Centipedegrass Attenuates Amyloid Plaques by Inducting Humoral Immune Response with Th2 Skewed Cytokine Response in the Tg (APPswe, PS1dE9) Alzheimer\u27s Mouse Model

Alzheimer\u27s disease (AD) is a slow, progressive neurodegenerative disease and the most common type of dementia in the elderly. The etiology of AD and its underlying mechanism are still not clear. In a previous study, we found that an ethyl acetate extract of Centipedegrass (CG) (i.e., EA-CG) contained 4 types of Maysin derivatives, including Luteolin, Isoorientin, Rhamnosylisoorientin, and Derhamnosylmaysin, and showed protective effects against Amyloid beta (Aβ) by inhibiting oligomeric Aβ in cellular and in vitro models. Here, we examined the preventative effects of EA-CG treatment on the Aβ burden in the Tg (Mo/Hu APPswe PS1dE9) AD mouse model. We have investigated the EA-CG efficacy as novel anti-AD likely preventing amyloid plaques using immunofluorescence staining to visually analyze Aβ40/42 and fibril formation with Thioflavin-S or 6E10 which are the profile of immunoreactivity against epitope Aβ1-16 or neuritic plaque, the quantitation of humoral immune response against Aβ, and the inflammatory cytokine responses (Th1 and Th2) using ELISA and QRT-PCR. To minimize the toxicity of the extracted CG, we addressed the liver toxicity in response to the CG extract treatment in Tg mice using relevant markers, such as aspartate aminotransferase (AST)/ alanine aminotransferase (ALT) measurements in serum. The EA-CG extract significantly reduced the Aβ burden, the concentration of soluble Aβ40/42 protein, and fibril formation in the hippocampus and cortex of the Tg mice treated with EA-CG (50 mg/kg BW/day) for 6 months compared with the Tg mice treated with a normal diet. Additionally, the profile of anti-inflammatory cytokines revealed that the levels of Th2 (interleukin-4 (IL-4) and interleukin-10 (IL-10)) cytokines are more significantly increased than Th1 (interferon-γ (IFN-γ), interleukin-2(IL-2)) in the sera. These results suggest that the EA-CG fraction induces IL-4/IL-10-dependent anti-inflammatory cytokines (Th2) rather than pro-inflammatory cytokines (Th1), which are driven by IL-2/IFN-γ. With regard to the immune response, EA-CG induced an immunoglobulin IgG and IgM response against the EA-CG treatment in the Tg mice. Furthermore, EA-CG significantly ameliorated the level of soluble Aβ42 and Aβ40. Similarly, we observed that the fibril formation was also decreased by EA-CG treatment in the hippocampus and cortex after quantitative analysis with Thioflavin-S staining in the Tg brain tissues. Taken together, our findings suggested that Maysin and its derivative flavonoid compounds in the EA-CG fraction might be beneficial therapeutic treatments or alternative preventative measures to adjuvant for boosting humoral and cellular include immune response and anti-inflammation which may lead to amyloid plaque accumulation in Alzheimer\u27s patients\u27 brains