Coins and Logic

We establish fun parallels between coin-weighing puzzles and knights-and-knaves puzzles.Comment: 18 pages, 2 figure

Modulation of Macrophage Activities in Proliferation, Lysosome, and Phagosome by the Nonspecific Immunostimulator, Mica

<div><p>It was reported that the aluminosilicate material mica activated macrophages and showed its immunostimulating effects. However, the mechanisms by which it exerts these effects are unclear. To address this, we evaluated the effects of mica fine particles (MFP, 804.1 ± 0.02 nm) on the murine macrophage cell line, RAW 264.7. Specifically, RAW 264.7 cells were treated with 100 and 500 μg/mL MFP and their proliferative response was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Changes in global gene expression upon MFP treatment for 12 and 48 h were also determined using microarrays. Following the MFP treatment, RAW 264.7 cells showed a low level of proliferation compared to nontreated cells (<i>p</i> < 0.01). There was a change in an expression level of 1,128 genes after 48 h treatment. Specifically, genes associated with the cell cycle, DNA replication, and pyrimidine and purine metabolisms, were down-regulated in cells treated with MFP, which resulted in reduction of cell proliferation. MFP treatment also up-regulated genes associated with lysosome and phagosome function, which are both required for macrophage activities. We speculate that activation of macrophages by mica is in part derived from up-regulation of these pathways.</p></div

Genes showing altered expression in the cell cycle pathway after treatment of MFP 100 μg/mL.

<p>Activation of p53 enhances expression of Gadd45 and Cip1 (<i>Cdkn1a</i>). Up-regulation of Gadd45 and Cip1 inhibit CycD (<i>Ccnd3</i>). CycE (<i>Ccne1</i> and <i>2</i>) and CycB (<i>Ccnd3</i>) are also down-regulated by Cip1 and Gadd45, respectively. Reduced expression of CDK1 (<i>Cdc2a</i>) leads to down-regulation of Plk1, which has critical function during mitosis. In addition, down-regulation of Cdc6, ORC (<i>Orc6l</i>), Cdc45 (<i>Cdc45l</i>), MCM, and EfF2 result in reduction of DNA synthesis. Reduced expression of APC/C (<i>Anapc5</i>) and Cdc20 down-regulates expression of Espl (<i>Espl1</i>), thereby affecting on chromosome segregation. This pathway map was conducted using KEGG mapper.</p

Categorization by molecular function of genes showing significant regulation.

<p>Up-regulated transcripts (A) and down-regulated transcripts (B) in RAW 264.7 macrophage at 12 h and 48 h post treatment with 100 μg/mL MFP. (<i>p</i> < 0.05, Fisher’s exact test)</p

Categorization by biological process of genes showing significant regulation.

<p>Up-regulated transcripts (A) and down-regulated transcripts (B) in RAW 264.7 macrophage at 12 h and 48 h post treatment with 100 μg/mL MFP. (<i>p</i> < 0.05, Fisher’s exact test)</p

Validation of microarray data <i>via</i> quantitative RT-PCR.

<p>The relative expression level was normalized to the level of GAPDH expression using the 2^-ΔΔCT method.</p

Proliferation of RAW 264.7 cells after treatment with 100 and 500 μg/mL of MFP.

<p>Cell proliferation was measured using the MTT assay.</p

Different gene expression after treatment with 100 μg/mL of MFP.

<p>(A) Count of up-and down-regulated genes in RAW 264.7 cells treated with MFP 100 μg/mL compared to nontreated. (0 h; <i>p</i> < 0.05, |fold change | ≥ 2). (B) and (C) Plots of the expression level between nontreated cells versus those treated with 100 μg/mL MFP for 12 or 48 h. Red dots present an expression level change of ≥ 2 or ≤ -2-fold for both up- and down-regulated genes. Expression levels were calculated by base 2 logarithm of normalized hybridization signals from each sample.</p

Unsupervised hierarchical clustering (A) and expression pattern profiles according to quality threshold clustering (B).

<p>The clustering results were determined using differentially expressed genes after treatment with 100 μg/mL of MFP. (<i>p</i> < 0.05, |fold change | ≥ 2)</p

SEM microphotographs (A) and the diameter distribution of mica fine particles (B).

<p>SEM microphotographs (A) and the diameter distribution of mica fine particles (B).</p