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Lysosomal membrane permeabilization and lysosomal damage induced by silica micro/nanoparticles in murine RAW-Blue
Dipankar Chandra Roy1, Kenji Ono1, Katsumi Fukamachi1
1Department of Neurotoxicology, Nagoya City University Graduate School of Medical Sciences and Medical School.
Abstract:
The objective of this study was to examine the mechanisms underlying endocytic uptake, cytotoxicity, oxidative stress, and lysosomal damage caused by silica micro/nanoparticles (SiPs) in murine RAW-Blue macrophages. In parallel studies, we also assessed the effects of NF-κB on lysosomal membrane permeabilization (LMP). Three types of SiPs, 3 μm-plain (3 μm diameter particles without surface modification), 50 nm-plain (50 nm diameter particles without surface modification), and 50 nm-NH2 (50 nm diameter particles with an amine functional group as surface modification) were tested. A significant decrease in cell proliferation and a significant increase in cell death were evident, when cells were treated with 50 nm-plain. All types of SiPs plus a lysosomal inhibitor caused a significant increase and a significant decrease in cell proliferation and cell death, respectively. When cells were treated with 50 nm-plain, puncta formation was seen. Treatment with 50 nm-plain significantly increased the expression level of inflammatory cytokine/chemokine genes, whereas inhibitors of clathrin-mediated endocytosis, lysosomal function, and cathepsin activity significantly attenuated these responses. Taken together, the present findings suggest that lysosomal dysfunction is closely associated with 50 nm-plain-induced cytotoxic and inflammatory responses. Our findings also provide relevant findings for safe and effective design of SiPs and a framework to maximize their biomedical potential while mitigating lysosomal damage.
Insights
Silica nanoparticles (SiPs) can cause cell damage and inflammation, particularly smaller, plain 50 nm particles. Lysosomal dysfunction is key to these cytotoxic effects, informing safer SiP design.
Area of Science:
- Nanotechnology
- Materials Science
- Toxicology
Background:
- Silica micro/nanoparticles (SiPs) are used in biomedical applications, but their cellular interactions and potential toxicity require thorough investigation.
- Understanding the mechanisms of SiP uptake, cytotoxicity, and inflammatory responses is crucial for safe material design.
Purpose of the Study:
- To investigate the cellular mechanisms of endocytic uptake, cytotoxicity, oxidative stress, and lysosomal damage induced by different types of SiPs in murine RAW-Blue macrophages.
- To assess the role of NF-κB signaling in lysosomal membrane permeabilization (LMP) caused by SiPs.
Main Methods:
- Exposure of RAW-Blue macrophages to three types of SiPs: 3 μm-plain, 50 nm-plain, and 50 nm-NH2.
- Assessment of cell proliferation, cell death, puncta formation, and inflammatory gene expression.
- Utilized inhibitors of clathrin-mediated endocytosis, lysosomal function, and cathepsin activity.
Main Results:
- 50 nm-plain SiPs significantly decreased cell proliferation and increased cell death.
- SiPs, especially 50 nm-plain, induced inflammatory responses, indicated by increased cytokine/chemokine gene expression.
- Inhibiting endocytosis, lysosomal function, or cathepsin activity attenuated SiP-induced inflammatory responses, highlighting lysosomal involvement.
Conclusions:
- Lysosomal dysfunction is closely linked to the cytotoxic and inflammatory effects of 50 nm-plain SiPs.
- Findings provide insights for designing safer SiPs with minimized lysosomal damage for biomedical applications.