Nanoparticles and Lung Response

15 mars 2023

How does the body react to the inhalation of nanoparticles? Scientists have studied the evolution of molybdenum disulfide nanosheets in mouse lungs up to one month after inhalation. Published in the journal Advanced Materials, these findings show that lung macrophages can transform these nanoparticles and wrap them in order to reduce their contact surface and thus their toxicity, and would also be able to modulate the induced inflammatory reaction.

The fate of nanoparticles in the biological environment is subject to significant surveillance. Evaluating their toxicity in the human body therefore requires understanding the inflammatory reactions they can cause. Among the nanoparticles of interest, molybdenum disulfide (MoS2) is a graphene analog widely used by industry, especially as a mechanical lubricant, which can be inadvertently inhaled.

Researchers from the Laboratories of Matter and Complex Systems (MSC, CNRS/University Paris Cité), Materials and Quantum Phenomena (MPQ, CNRS/University Paris Cité), Immunology, Immunopathology and Therapeutic Chemistry (I2CT, CNRS) and the Galien Paris-Saclay Institute (IGPS, CNRS/University Paris-Saclay) studied the long-term persistence of MoS2 nanosheets in the lungs of mice exposed to them. They thus scrutinized the transformations of these nanoparticles while monitoring different inflammation biomarkers in the lungs.

To do this, scientists multiplied observations by electron microscopy in biological samples taken from lungs at different times while bronchoalveolar lavages were performed successively up to one month after exposure to MoS2. In parallel, they observed in real-time the dynamics of nanosheet transformation in a cellular medium model, using an innovative technique of electron microscopy in liquid medium.

Published in the journal Advanced Materials, the results show that cells, especially lung macrophages, are capable of oxidizing and dissolving these nanoparticles, thereby probably making them less toxic. A mechanism of self-wrapping of the nanosheets was highlighted, which reduces their surface capable of reacting harmfully with cells. The second important result involves membrane nanovesicles, also called extracellular vesicles, which cells are capable of emitting into the extracellular medium to communicate with each other. Extracellular vesicles isolated from bronchoalveolar fluids of mice exposed to MoS2 reduce the expression of inflammation signals in immune cells, more than those from unexposed mice. This could mean that these vesicles transport different inflammation regulators and evacuate waste from nanoparticles to the outside of cells.

Based on these results, the teams intend to deepen this work and extend it to other organs and other nanoparticles, such as titanium dioxide.