Amorphous silica nanoparticles alter microtubule dynamics and cell migration

Area of Science:

• Nanotoxicology
• Cell Biology
• Biophysics

Background:

• Amorphous silica nanoparticles (SiO2-NPs) raise concerns regarding toxicity and genotoxicity.
• Previous studies suggest SiO2-NPs may target the microtubule (MT) network, potentially causing aneugenic events.
• Contradictory data and unclear mechanisms necessitate further investigation into SiO2-NP interactions with cellular structures.

Purpose of the Study:

• To investigate the direct effects of amorphous SiO2-NPs on the microtubule (MT) network in A549 human lung carcinoma cells.
• To determine if SiO2-NPs influence MT dynamics, acetylation, and cell motility.
• To assess the role of MTs as a direct target of SiO2-NPs, independent of toxicity or genotoxicity.

Main Methods:

• Exposure of A549 cells to two sizes of SiO2-NPs (59 nm and 174 nm) under serum-free conditions.
• Analysis of MTs in mitotic and interphase cells, including spindle morphology and MT network dynamics via in situ depolymerisation/repolymerisation.
• Assessment of MT acetylation levels and cell motility using live cell microscopy.

Main Results:

• SiO2-NPs did not induce significant changes in mitotic spindle morphology or multipolar spindles.
• A notable increase in interphase MT network dynamics was observed post-SiO2-NP treatment.
• Reduced MT acetylation and decreased A549 cell motility were detected following SiO2-NP exposure.
• No significant cell toxicity or micronuclei formation was observed at the tested doses.

Conclusions:

• The observed effects on MT dynamics, MT acetylation, and cell migration are direct consequences of SiO2-NP interaction.
• The microtubule network is a direct target of SiO2-NPs, influencing cellular processes beyond toxicity.
• These findings contribute to understanding the non-genotoxic mechanisms of SiO2-NP action at the cellular level.