Abstract
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 (p < 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.
Highlights
Mica, which is well known for its immunostimulating effects, is a common aluminosilicate mineral containing potassium, magnesium, iron, aluminum, and silicates
Pattern as mica fine particles (MFP) 100 μg/mL treatment, showing high level of proliferative responses compared to the MFP treatment (p < 0.01)
We suggest that the up-regulation of lysosome- and phagosome-associated genes observed in this study may indicate enhanced macrophage activities, which in turn would enhance the responses of antigen presentation [32, 35, 36]
Summary
Mica, which is well known for its immunostimulating effects, is a common aluminosilicate mineral containing potassium, magnesium, iron, aluminum, and silicates. The immunostimulating effects of mica have been proven through many previous studies [1,2,3,4,5]. Mica has been used as feed supplement to improve immune activities [3,4,5] and increase an absorption rate of high-protein nutrients [1, 2]. As described in the above study results, most studies using mica have been concentrated on the proof of the immune enhancement effects but few studies have been done on the mechanism of how the immunity enhancement effect is induced. It was reported that mica activated macrophages and the immunity enhancement effect was induced by this activation of the macrophages [6].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
